ALSA: usb-audio: add support for Akai MPD16
[safe/jmp/linux-2.6] / drivers / ide / ide-tape.c
index a99e28f..b072328 100644 (file)
@@ -31,6 +31,7 @@
 #include <linux/major.h>
 #include <linux/errno.h>
 #include <linux/genhd.h>
+#include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
 #include <linux/ide.h>
 #include <asm/unaligned.h>
 #include <linux/mtio.h>
 
-enum {
-       /* output errors only */
-       DBG_ERR =               (1 << 0),
-       /* output all sense key/asc */
-       DBG_SENSE =             (1 << 1),
-       /* info regarding all chrdev-related procedures */
-       DBG_CHRDEV =            (1 << 2),
-       /* all remaining procedures */
-       DBG_PROCS =             (1 << 3),
-};
-
 /* define to see debug info */
-#define IDETAPE_DEBUG_LOG              0
+#undef IDETAPE_DEBUG_LOG
 
-#if IDETAPE_DEBUG_LOG
-#define debug_log(lvl, fmt, args...)                   \
-{                                                      \
-       if (tape->debug_mask & lvl)                     \
-       printk(KERN_INFO "ide-tape: " fmt, ## args);    \
-}
+#ifdef IDETAPE_DEBUG_LOG
+#define ide_debug_log(lvl, fmt, args...) __ide_debug_log(lvl, fmt, ## args)
 #else
-#define debug_log(lvl, fmt, args...) do {} while (0)
+#define ide_debug_log(lvl, fmt, args...) do {} while (0)
 #endif
 
 /**************************** Tunable parameters *****************************/
@@ -131,13 +117,6 @@ enum {
        IDETAPE_DIR_WRITE = (1 << 2),
 };
 
-struct idetape_bh {
-       u32 b_size;
-       atomic_t b_count;
-       struct idetape_bh *b_reqnext;
-       char *b_data;
-};
-
 /* Tape door status */
 #define DOOR_UNLOCKED                  0
 #define DOOR_LOCKED                    1
@@ -152,11 +131,6 @@ struct idetape_bh {
 #define IDETAPE_LU_RETENSION_MASK      2
 #define IDETAPE_LU_EOT_MASK            4
 
-/* Error codes returned in rq->errors to the higher part of the driver. */
-#define IDETAPE_ERROR_GENERAL          101
-#define IDETAPE_ERROR_FILEMARK         102
-#define IDETAPE_ERROR_EOD              103
-
 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
 #define IDETAPE_BLOCK_DESCRIPTOR       0
 #define IDETAPE_CAPABILITIES_PAGE      0x2a
@@ -166,19 +140,11 @@ struct idetape_bh {
  * to an interrupt or a timer event is stored in the struct defined below.
  */
 typedef struct ide_tape_obj {
-       ide_drive_t     *drive;
-       ide_driver_t    *driver;
-       struct gendisk  *disk;
-       struct kref     kref;
+       ide_drive_t             *drive;
+       struct ide_driver       *driver;
+       struct gendisk          *disk;
+       struct device           dev;
 
-       /*
-        *      failed_pc points to the last failed packet command, or contains
-        *      NULL if we do not need to retry any packet command. This is
-        *      required since an additional packet command is needed before the
-        *      retry, to get detailed information on what went wrong.
-        */
-       /* Last failed packet command */
-       struct ide_atapi_pc *failed_pc;
        /* used by REQ_IDETAPE_{READ,WRITE} requests */
        struct ide_atapi_pc queued_pc;
 
@@ -190,7 +156,8 @@ typedef struct ide_tape_obj {
         * other device. Note that at most we will have only one DSC (usually
         * data transfer) request in the device request queue.
         */
-       struct request *postponed_rq;
+       bool postponed_rq;
+
        /* The time in which we started polling for DSC */
        unsigned long dsc_polling_start;
        /* Timer used to poll for dsc */
@@ -232,21 +199,12 @@ typedef struct ide_tape_obj {
 
        /* Data buffer size chosen based on the tape's recommendation */
        int buffer_size;
-       /* merge buffer */
-       struct idetape_bh *merge_bh;
-       /* size of the merge buffer */
-       int merge_bh_size;
-       /* pointer to current buffer head within the merge buffer */
-       struct idetape_bh *bh;
-       char *b_data;
-       int b_count;
-
-       int pages_per_buffer;
-       /* Wasted space in each stage */
-       int excess_bh_size;
-
-       /* protects the ide-tape queue */
-       spinlock_t lock;
+       /* Staging buffer of buffer_size bytes */
+       void *buf;
+       /* The read/write cursor */
+       void *cur;
+       /* The number of valid bytes in buf */
+       size_t valid;
 
        /* Measures average tape speed */
        unsigned long avg_time;
@@ -259,28 +217,37 @@ typedef struct ide_tape_obj {
        char drv_write_prot;
        /* the tape is write protected (hardware or opened as read-only) */
        char write_prot;
-
-       u32 debug_mask;
 } idetape_tape_t;
 
 static DEFINE_MUTEX(idetape_ref_mutex);
 
+static DEFINE_MUTEX(idetape_chrdev_mutex);
+
 static struct class *idetape_sysfs_class;
 
-static void ide_tape_release(struct kref *);
+static void ide_tape_release(struct device *);
 
-static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
+static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
+
+static struct ide_tape_obj *ide_tape_get(struct gendisk *disk, bool cdev,
+                                        unsigned int i)
 {
        struct ide_tape_obj *tape = NULL;
 
        mutex_lock(&idetape_ref_mutex);
-       tape = ide_drv_g(disk, ide_tape_obj);
+
+       if (cdev)
+               tape = idetape_devs[i];
+       else
+               tape = ide_drv_g(disk, ide_tape_obj);
+
        if (tape) {
                if (ide_device_get(tape->drive))
                        tape = NULL;
                else
-                       kref_get(&tape->kref);
+                       get_device(&tape->dev);
        }
+
        mutex_unlock(&idetape_ref_mutex);
        return tape;
 }
@@ -290,132 +257,33 @@ static void ide_tape_put(struct ide_tape_obj *tape)
        ide_drive_t *drive = tape->drive;
 
        mutex_lock(&idetape_ref_mutex);
-       kref_put(&tape->kref, ide_tape_release);
+       put_device(&tape->dev);
        ide_device_put(drive);
        mutex_unlock(&idetape_ref_mutex);
 }
 
 /*
- * The variables below are used for the character device interface. Additional
- * state variables are defined in our ide_drive_t structure.
- */
-static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
-
-static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
-{
-       struct ide_tape_obj *tape = NULL;
-
-       mutex_lock(&idetape_ref_mutex);
-       tape = idetape_devs[i];
-       if (tape)
-               kref_get(&tape->kref);
-       mutex_unlock(&idetape_ref_mutex);
-       return tape;
-}
-
-static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
-                                 unsigned int bcount)
-{
-       struct idetape_bh *bh = pc->bh;
-       int count;
-
-       while (bcount) {
-               if (bh == NULL) {
-                       printk(KERN_ERR "ide-tape: bh == NULL in "
-                               "idetape_input_buffers\n");
-                       ide_pad_transfer(drive, 0, bcount);
-                       return;
-               }
-               count = min(
-                       (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
-                       bcount);
-               drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
-                                       atomic_read(&bh->b_count), count);
-               bcount -= count;
-               atomic_add(count, &bh->b_count);
-               if (atomic_read(&bh->b_count) == bh->b_size) {
-                       bh = bh->b_reqnext;
-                       if (bh)
-                               atomic_set(&bh->b_count, 0);
-               }
-       }
-       pc->bh = bh;
-}
-
-static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
-                                  unsigned int bcount)
-{
-       struct idetape_bh *bh = pc->bh;
-       int count;
-
-       while (bcount) {
-               if (bh == NULL) {
-                       printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
-                                       __func__);
-                       return;
-               }
-               count = min((unsigned int)pc->b_count, (unsigned int)bcount);
-               drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
-               bcount -= count;
-               pc->b_data += count;
-               pc->b_count -= count;
-               if (!pc->b_count) {
-                       bh = bh->b_reqnext;
-                       pc->bh = bh;
-                       if (bh) {
-                               pc->b_data = bh->b_data;
-                               pc->b_count = atomic_read(&bh->b_count);
-                       }
-               }
-       }
-}
-
-static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
-{
-       struct idetape_bh *bh = pc->bh;
-       int count;
-       unsigned int bcount = pc->xferred;
-
-       if (pc->flags & PC_FLAG_WRITING)
-               return;
-       while (bcount) {
-               if (bh == NULL) {
-                       printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
-                                       __func__);
-                       return;
-               }
-               count = min((unsigned int)bh->b_size, (unsigned int)bcount);
-               atomic_set(&bh->b_count, count);
-               if (atomic_read(&bh->b_count) == bh->b_size)
-                       bh = bh->b_reqnext;
-               bcount -= count;
-       }
-       pc->bh = bh;
-}
-
-/*
  * called on each failed packet command retry to analyze the request sense. We
  * currently do not utilize this information.
  */
-static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
+static void idetape_analyze_error(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
-       struct ide_atapi_pc *pc = tape->failed_pc;
+       struct ide_atapi_pc *pc = drive->failed_pc;
+       struct request *rq = drive->hwif->rq;
+       u8 *sense = bio_data(rq->bio);
 
        tape->sense_key = sense[2] & 0xF;
        tape->asc       = sense[12];
        tape->ascq      = sense[13];
 
-       debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
-                pc->c[0], tape->sense_key, tape->asc, tape->ascq);
+       ide_debug_log(IDE_DBG_FUNC,
+                     "cmd: 0x%x, sense key = %x, asc = %x, ascq = %x",
+                     rq->cmd[0], tape->sense_key, tape->asc, tape->ascq);
 
-       /* Correct pc->xferred by asking the tape.       */
-       if (pc->flags & PC_FLAG_DMA_ERROR) {
-               pc->xferred = pc->req_xfer -
-                       tape->blk_size *
-                       get_unaligned_be32(&sense[3]);
-               idetape_update_buffers(drive, pc);
-       }
+       /* correct remaining bytes to transfer */
+       if (pc->flags & PC_FLAG_DMA_ERROR)
+               rq->resid_len = tape->blk_size * get_unaligned_be32(&sense[3]);
 
        /*
         * If error was the result of a zero-length read or write command,
@@ -433,106 +301,55 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
                }
        }
        if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
-               pc->error = IDETAPE_ERROR_FILEMARK;
+               pc->error = IDE_DRV_ERROR_FILEMARK;
                pc->flags |= PC_FLAG_ABORT;
        }
        if (pc->c[0] == WRITE_6) {
                if ((sense[2] & 0x40) || (tape->sense_key == 0xd
                     && tape->asc == 0x0 && tape->ascq == 0x2)) {
-                       pc->error = IDETAPE_ERROR_EOD;
+                       pc->error = IDE_DRV_ERROR_EOD;
                        pc->flags |= PC_FLAG_ABORT;
                }
        }
        if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
                if (tape->sense_key == 8) {
-                       pc->error = IDETAPE_ERROR_EOD;
+                       pc->error = IDE_DRV_ERROR_EOD;
                        pc->flags |= PC_FLAG_ABORT;
                }
                if (!(pc->flags & PC_FLAG_ABORT) &&
-                   pc->xferred)
+                   (blk_rq_bytes(rq) - rq->resid_len))
                        pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
        }
 }
 
-/* Free data buffers completely. */
-static void ide_tape_kfree_buffer(idetape_tape_t *tape)
-{
-       struct idetape_bh *prev_bh, *bh = tape->merge_bh;
-
-       while (bh) {
-               u32 size = bh->b_size;
-
-               while (size) {
-                       unsigned int order = fls(size >> PAGE_SHIFT)-1;
-
-                       if (bh->b_data)
-                               free_pages((unsigned long)bh->b_data, order);
-
-                       size &= (order-1);
-                       bh->b_data += (1 << order) * PAGE_SIZE;
-               }
-               prev_bh = bh;
-               bh = bh->b_reqnext;
-               kfree(prev_bh);
-       }
-}
-
-static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
-{
-       struct request *rq = HWGROUP(drive)->rq;
-       idetape_tape_t *tape = drive->driver_data;
-       unsigned long flags;
-       int error;
-
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
-
-       switch (uptodate) {
-       case 0: error = IDETAPE_ERROR_GENERAL; break;
-       case 1: error = 0; break;
-       default: error = uptodate;
-       }
-       rq->errors = error;
-       if (error)
-               tape->failed_pc = NULL;
-
-       if (!blk_special_request(rq)) {
-               ide_end_request(drive, uptodate, nr_sects);
-               return 0;
-       }
-
-       spin_lock_irqsave(&tape->lock, flags);
-
-       ide_end_drive_cmd(drive, 0, 0);
-
-       spin_unlock_irqrestore(&tape->lock, flags);
-       return 0;
-}
-
 static void ide_tape_handle_dsc(ide_drive_t *);
 
-static void ide_tape_callback(ide_drive_t *drive, int dsc)
+static int ide_tape_callback(ide_drive_t *drive, int dsc)
 {
        idetape_tape_t *tape = drive->driver_data;
        struct ide_atapi_pc *pc = drive->pc;
+       struct request *rq = drive->hwif->rq;
        int uptodate = pc->error ? 0 : 1;
+       int err = uptodate ? 0 : IDE_DRV_ERROR_GENERAL;
 
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
+       ide_debug_log(IDE_DBG_FUNC, "cmd: 0x%x, dsc: %d, err: %d", rq->cmd[0],
+                     dsc, err);
 
        if (dsc)
                ide_tape_handle_dsc(drive);
 
-       if (tape->failed_pc == pc)
-               tape->failed_pc = NULL;
+       if (drive->failed_pc == pc)
+               drive->failed_pc = NULL;
 
        if (pc->c[0] == REQUEST_SENSE) {
                if (uptodate)
-                       idetape_analyze_error(drive, pc->buf);
+                       idetape_analyze_error(drive);
                else
                        printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
                                        "itself - Aborting request!\n");
        } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
-               struct request *rq = drive->hwif->hwgroup->rq;
-               int blocks = pc->xferred / tape->blk_size;
+               unsigned int blocks =
+                       (blk_rq_bytes(rq) - rq->resid_len) / tape->blk_size;
 
                tape->avg_size += blocks * tape->blk_size;
 
@@ -544,47 +361,30 @@ static void ide_tape_callback(ide_drive_t *drive, int dsc)
                }
 
                tape->first_frame += blocks;
-               rq->current_nr_sectors -= blocks;
-
-               if (pc->error)
-                       uptodate = pc->error;
-       } else if (pc->c[0] == READ_POSITION && uptodate) {
-               u8 *readpos = pc->buf;
 
-               debug_log(DBG_SENSE, "BOP - %s\n",
-                               (readpos[0] & 0x80) ? "Yes" : "No");
-               debug_log(DBG_SENSE, "EOP - %s\n",
-                               (readpos[0] & 0x40) ? "Yes" : "No");
-
-               if (readpos[0] & 0x4) {
-                       printk(KERN_INFO "ide-tape: Block location is unknown"
-                                        "to the tape\n");
-                       clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
+               if (pc->error) {
                        uptodate = 0;
-               } else {
-                       debug_log(DBG_SENSE, "Block Location - %u\n",
-                                       be32_to_cpup((__be32 *)&readpos[4]));
-
-                       tape->partition = readpos[1];
-                       tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
-                       set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
+                       err = pc->error;
                }
        }
+       rq->errors = err;
 
-       idetape_end_request(drive, uptodate, 0);
+       return uptodate;
 }
 
 /*
  * Postpone the current request so that ide.c will be able to service requests
- * from another device on the same hwgroup while we are polling for DSC.
+ * from another device on the same port while we are polling for DSC.
  */
-static void idetape_postpone_request(ide_drive_t *drive)
+static void ide_tape_stall_queue(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
 
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
+       ide_debug_log(IDE_DBG_FUNC, "cmd: 0x%x, dsc_poll_freq: %lu",
+                     drive->hwif->rq->cmd[0], tape->dsc_poll_freq);
+
+       tape->postponed_rq = true;
 
-       tape->postponed_rq = HWGROUP(drive)->rq;
        ide_stall_queue(drive, tape->dsc_poll_freq);
 }
 
@@ -597,18 +397,7 @@ static void ide_tape_handle_dsc(ide_drive_t *drive)
        tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
        tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
        /* Allow ide.c to handle other requests */
-       idetape_postpone_request(drive);
-}
-
-static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
-                               unsigned int bcount, int write)
-{
-       if (write)
-               idetape_output_buffers(drive, pc, bcount);
-       else
-               idetape_input_buffers(drive, pc, bcount);
-
-       return bcount;
+       ide_tape_stall_queue(drive);
 }
 
 /*
@@ -620,7 +409,7 @@ static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
  *
  * The handling will be done in three stages:
  *
- * 1. idetape_issue_pc will send the packet command to the drive, and will set
+ * 1. ide_tape_issue_pc will send the packet command to the drive, and will set
  * the interrupt handler to ide_pc_intr.
  *
  * 2. On each interrupt, ide_pc_intr will be called. This step will be
@@ -648,25 +437,22 @@ static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
  * request.
  */
 
-static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
-               struct ide_atapi_pc *pc)
+static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive,
+                                        struct ide_cmd *cmd,
+                                        struct ide_atapi_pc *pc)
 {
        idetape_tape_t *tape = drive->driver_data;
+       struct request *rq = drive->hwif->rq;
 
-       if (drive->pc->c[0] == REQUEST_SENSE &&
-           pc->c[0] == REQUEST_SENSE) {
-               printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
-                       "Two request sense in serial were issued\n");
-       }
-
-       if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
-               tape->failed_pc = pc;
+       if (drive->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
+               drive->failed_pc = pc;
 
        /* Set the current packet command */
        drive->pc = pc;
 
        if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
                (pc->flags & PC_FLAG_ABORT)) {
+
                /*
                 * We will "abort" retrying a packet command in case legitimate
                 * error code was received (crossing a filemark, or end of the
@@ -684,17 +470,20 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
                                                tape->ascq);
                        }
                        /* Giving up */
-                       pc->error = IDETAPE_ERROR_GENERAL;
+                       pc->error = IDE_DRV_ERROR_GENERAL;
                }
-               tape->failed_pc = NULL;
+
+               drive->failed_pc = NULL;
                drive->pc_callback(drive, 0);
+               ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
                return ide_stopped;
        }
-       debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
+       ide_debug_log(IDE_DBG_SENSE, "retry #%d, cmd: 0x%02x", pc->retries,
+                     pc->c[0]);
 
        pc->retries++;
 
-       return ide_issue_pc(drive, WAIT_TAPE_CMD, NULL);
+       return ide_issue_pc(drive, cmd);
 }
 
 /* A mode sense command is used to "sense" tape parameters. */
@@ -740,13 +529,13 @@ static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
                                printk(KERN_ERR "ide-tape: %s: I/O error, ",
                                                tape->name);
                        /* Retry operation */
-                       ide_retry_pc(drive, tape->disk);
+                       ide_retry_pc(drive);
                        return ide_stopped;
                }
                pc->error = 0;
        } else {
-               pc->error = IDETAPE_ERROR_GENERAL;
-               tape->failed_pc = NULL;
+               pc->error = IDE_DRV_ERROR_GENERAL;
+               drive->failed_pc = NULL;
        }
        drive->pc_callback(drive, 0);
        return ide_stopped;
@@ -756,27 +545,20 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
                                   struct ide_atapi_pc *pc, struct request *rq,
                                   u8 opcode)
 {
-       struct idetape_bh *bh = (struct idetape_bh *)rq->special;
-       unsigned int length = rq->current_nr_sectors;
+       unsigned int length = blk_rq_sectors(rq) / (tape->blk_size >> 9);
 
        ide_init_pc(pc);
        put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
        pc->c[1] = 1;
-       pc->bh = bh;
-       pc->buf = NULL;
-       pc->buf_size = length * tape->blk_size;
-       pc->req_xfer = pc->buf_size;
-       if (pc->req_xfer == tape->buffer_size)
+
+       if (blk_rq_bytes(rq) == tape->buffer_size)
                pc->flags |= PC_FLAG_DMA_OK;
 
-       if (opcode == READ_6) {
+       if (opcode == READ_6)
                pc->c[0] = READ_6;
-               atomic_set(&bh->b_count, 0);
-       } else if (opcode == WRITE_6) {
+       else if (opcode == WRITE_6) {
                pc->c[0] = WRITE_6;
                pc->flags |= PC_FLAG_WRITING;
-               pc->b_data = bh->b_data;
-               pc->b_count = atomic_read(&bh->b_count);
        }
 
        memcpy(rq->cmd, pc->c, 12);
@@ -788,38 +570,21 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
        ide_hwif_t *hwif = drive->hwif;
        idetape_tape_t *tape = drive->driver_data;
        struct ide_atapi_pc *pc = NULL;
-       struct request *postponed_rq = tape->postponed_rq;
+       struct ide_cmd cmd;
        u8 stat;
 
-       debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
-                       " current_nr_sectors: %u\n",
-                       (unsigned long long)rq->sector, rq->nr_sectors,
-                       rq->current_nr_sectors);
+       ide_debug_log(IDE_DBG_RQ, "cmd: 0x%x, sector: %llu, nr_sectors: %u",
+                     rq->cmd[0], (unsigned long long)blk_rq_pos(rq),
+                     blk_rq_sectors(rq));
 
-       if (!blk_special_request(rq)) {
-               /* We do not support buffer cache originated requests. */
-               printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
-                       "request queue (%d)\n", drive->name, rq->cmd_type);
-               ide_end_request(drive, 0, 0);
-               return ide_stopped;
-       }
+       BUG_ON(!(blk_special_request(rq) || blk_sense_request(rq)));
 
        /* Retry a failed packet command */
-       if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
-               pc = tape->failed_pc;
+       if (drive->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
+               pc = drive->failed_pc;
                goto out;
        }
 
-       if (postponed_rq != NULL)
-               if (rq != postponed_rq) {
-                       printk(KERN_ERR "ide-tape: ide-tape.c bug - "
-                                       "Two DSC requests were queued\n");
-                       idetape_end_request(drive, 0, 0);
-                       return ide_stopped;
-               }
-
-       tape->postponed_rq = NULL;
-
        /*
         * If the tape is still busy, postpone our request and service
         * the other device meanwhile.
@@ -828,16 +593,16 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 
        if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
            (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
-               set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
+               drive->atapi_flags |= IDE_AFLAG_IGNORE_DSC;
 
        if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
-               set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
+               drive->atapi_flags |= IDE_AFLAG_IGNORE_DSC;
                drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
        }
 
-       if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
-           (stat & ATA_DSC) == 0) {
-               if (postponed_rq == NULL) {
+       if (!(drive->atapi_flags & IDE_AFLAG_IGNORE_DSC) &&
+           !(stat & ATA_DSC)) {
+               if (!tape->postponed_rq) {
                        tape->dsc_polling_start = jiffies;
                        tape->dsc_poll_freq = tape->best_dsc_rw_freq;
                        tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
@@ -854,9 +619,13 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
                                        tape->dsc_polling_start +
                                        IDETAPE_DSC_MA_THRESHOLD))
                        tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
-               idetape_postpone_request(drive);
+               ide_tape_stall_queue(drive);
                return ide_stopped;
+       } else {
+               drive->atapi_flags &= ~IDE_AFLAG_IGNORE_DSC;
+               tape->postponed_rq = false;
        }
+
        if (rq->cmd[13] & REQ_IDETAPE_READ) {
                pc = &tape->queued_pc;
                ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
@@ -868,7 +637,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
                goto out;
        }
        if (rq->cmd[13] & REQ_IDETAPE_PC1) {
-               pc = (struct ide_atapi_pc *) rq->buffer;
+               pc = (struct ide_atapi_pc *)rq->special;
                rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
                rq->cmd[13] |= REQ_IDETAPE_PC2;
                goto out;
@@ -880,167 +649,20 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
        BUG();
 
 out:
-       return idetape_issue_pc(drive, pc);
-}
-
-/*
- * The function below uses __get_free_pages to allocate a data buffer of size
- * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
- * much as possible.
- *
- * It returns a pointer to the newly allocated buffer, or NULL in case of
- * failure.
- */
-static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
-                                                 int full, int clear)
-{
-       struct idetape_bh *prev_bh, *bh, *merge_bh;
-       int pages = tape->pages_per_buffer;
-       unsigned int order, b_allocd;
-       char *b_data = NULL;
-
-       merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
-       bh = merge_bh;
-       if (bh == NULL)
-               goto abort;
-
-       order = fls(pages) - 1;
-       bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
-       if (!bh->b_data)
-               goto abort;
-       b_allocd = (1 << order) * PAGE_SIZE;
-       pages &= (order-1);
-
-       if (clear)
-               memset(bh->b_data, 0, b_allocd);
-       bh->b_reqnext = NULL;
-       bh->b_size = b_allocd;
-       atomic_set(&bh->b_count, full ? bh->b_size : 0);
-
-       while (pages) {
-               order = fls(pages) - 1;
-               b_data = (char *) __get_free_pages(GFP_KERNEL, order);
-               if (!b_data)
-                       goto abort;
-               b_allocd = (1 << order) * PAGE_SIZE;
-
-               if (clear)
-                       memset(b_data, 0, b_allocd);
-
-               /* newly allocated page frames below buffer header or ...*/
-               if (bh->b_data == b_data + b_allocd) {
-                       bh->b_size += b_allocd;
-                       bh->b_data -= b_allocd;
-                       if (full)
-                               atomic_add(b_allocd, &bh->b_count);
-                       continue;
-               }
-               /* they are above the header */
-               if (b_data == bh->b_data + bh->b_size) {
-                       bh->b_size += b_allocd;
-                       if (full)
-                               atomic_add(b_allocd, &bh->b_count);
-                       continue;
-               }
-               prev_bh = bh;
-               bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
-               if (!bh) {
-                       free_pages((unsigned long) b_data, order);
-                       goto abort;
-               }
-               bh->b_reqnext = NULL;
-               bh->b_data = b_data;
-               bh->b_size = b_allocd;
-               atomic_set(&bh->b_count, full ? bh->b_size : 0);
-               prev_bh->b_reqnext = bh;
+       /* prepare sense request for this command */
+       ide_prep_sense(drive, rq);
 
-               pages &= (order-1);
-       }
+       memset(&cmd, 0, sizeof(cmd));
 
-       bh->b_size -= tape->excess_bh_size;
-       if (full)
-               atomic_sub(tape->excess_bh_size, &bh->b_count);
-       return merge_bh;
-abort:
-       ide_tape_kfree_buffer(tape);
-       return NULL;
-}
-
-static int idetape_copy_stage_from_user(idetape_tape_t *tape,
-                                       const char __user *buf, int n)
-{
-       struct idetape_bh *bh = tape->bh;
-       int count;
-       int ret = 0;
-
-       while (n) {
-               if (bh == NULL) {
-                       printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
-                                       __func__);
-                       return 1;
-               }
-               count = min((unsigned int)
-                               (bh->b_size - atomic_read(&bh->b_count)),
-                               (unsigned int)n);
-               if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
-                               count))
-                       ret = 1;
-               n -= count;
-               atomic_add(count, &bh->b_count);
-               buf += count;
-               if (atomic_read(&bh->b_count) == bh->b_size) {
-                       bh = bh->b_reqnext;
-                       if (bh)
-                               atomic_set(&bh->b_count, 0);
-               }
-       }
-       tape->bh = bh;
-       return ret;
-}
+       if (rq_data_dir(rq))
+               cmd.tf_flags |= IDE_TFLAG_WRITE;
 
-static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
-                                     int n)
-{
-       struct idetape_bh *bh = tape->bh;
-       int count;
-       int ret = 0;
-
-       while (n) {
-               if (bh == NULL) {
-                       printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
-                                       __func__);
-                       return 1;
-               }
-               count = min(tape->b_count, n);
-               if  (copy_to_user(buf, tape->b_data, count))
-                       ret = 1;
-               n -= count;
-               tape->b_data += count;
-               tape->b_count -= count;
-               buf += count;
-               if (!tape->b_count) {
-                       bh = bh->b_reqnext;
-                       tape->bh = bh;
-                       if (bh) {
-                               tape->b_data = bh->b_data;
-                               tape->b_count = atomic_read(&bh->b_count);
-                       }
-               }
-       }
-       return ret;
-}
+       cmd.rq = rq;
 
-static void idetape_init_merge_buffer(idetape_tape_t *tape)
-{
-       struct idetape_bh *bh = tape->merge_bh;
-       tape->bh = tape->merge_bh;
+       ide_init_sg_cmd(&cmd, blk_rq_bytes(rq));
+       ide_map_sg(drive, &cmd);
 
-       if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
-               atomic_set(&bh->b_count, 0);
-       else {
-               tape->b_data = bh->b_data;
-               tape->b_count = atomic_read(&bh->b_count);
-       }
+       return ide_tape_issue_pc(drive, &cmd, pc);
 }
 
 /*
@@ -1063,7 +685,7 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
        int load_attempted = 0;
 
        /* Wait for the tape to become ready */
-       set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
+       set_bit(ilog2(IDE_AFLAG_MEDIUM_PRESENT), &drive->atapi_flags);
        timeout += jiffies;
        while (time_before(jiffies, timeout)) {
                if (ide_do_test_unit_ready(drive, disk) == 0)
@@ -1091,33 +713,53 @@ static int idetape_flush_tape_buffers(ide_drive_t *drive)
        int rc;
 
        idetape_create_write_filemark_cmd(drive, &pc, 0);
-       rc = ide_queue_pc_tail(drive, tape->disk, &pc);
+       rc = ide_queue_pc_tail(drive, tape->disk, &pc, NULL, 0);
        if (rc)
                return rc;
        idetape_wait_ready(drive, 60 * 5 * HZ);
        return 0;
 }
 
-static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
-{
-       ide_init_pc(pc);
-       pc->c[0] = READ_POSITION;
-       pc->req_xfer = 20;
-}
-
-static int idetape_read_position(ide_drive_t *drive)
+static int ide_tape_read_position(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
        struct ide_atapi_pc pc;
-       int position;
+       u8 buf[20];
+
+       ide_debug_log(IDE_DBG_FUNC, "enter");
 
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
+       /* prep cmd */
+       ide_init_pc(&pc);
+       pc.c[0] = READ_POSITION;
+       pc.req_xfer = 20;
 
-       idetape_create_read_position_cmd(&pc);
-       if (ide_queue_pc_tail(drive, tape->disk, &pc))
+       if (ide_queue_pc_tail(drive, tape->disk, &pc, buf, pc.req_xfer))
                return -1;
-       position = tape->first_frame;
-       return position;
+
+       if (!pc.error) {
+               ide_debug_log(IDE_DBG_FUNC, "BOP - %s",
+                               (buf[0] & 0x80) ? "Yes" : "No");
+               ide_debug_log(IDE_DBG_FUNC, "EOP - %s",
+                               (buf[0] & 0x40) ? "Yes" : "No");
+
+               if (buf[0] & 0x4) {
+                       printk(KERN_INFO "ide-tape: Block location is unknown"
+                                        "to the tape\n");
+                       clear_bit(ilog2(IDE_AFLAG_ADDRESS_VALID),
+                                 &drive->atapi_flags);
+                       return -1;
+               } else {
+                       ide_debug_log(IDE_DBG_FUNC, "Block Location: %u",
+                                     be32_to_cpup((__be32 *)&buf[4]));
+
+                       tape->partition = buf[1];
+                       tape->first_frame = be32_to_cpup((__be32 *)&buf[4]);
+                       set_bit(ilog2(IDE_AFLAG_ADDRESS_VALID),
+                               &drive->atapi_flags);
+               }
+       }
+
+       return tape->first_frame;
 }
 
 static void idetape_create_locate_cmd(ide_drive_t *drive,
@@ -1139,11 +781,11 @@ static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
        if (tape->chrdev_dir != IDETAPE_DIR_READ)
                return;
 
-       clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
-       tape->merge_bh_size = 0;
-       if (tape->merge_bh != NULL) {
-               ide_tape_kfree_buffer(tape);
-               tape->merge_bh = NULL;
+       clear_bit(ilog2(IDE_AFLAG_FILEMARK), &drive->atapi_flags);
+       tape->valid = 0;
+       if (tape->buf != NULL) {
+               kfree(tape->buf);
+               tape->buf = NULL;
        }
 
        tape->chrdev_dir = IDETAPE_DIR_NONE;
@@ -1160,19 +802,21 @@ static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
 {
        idetape_tape_t *tape = drive->driver_data;
        struct gendisk *disk = tape->disk;
-       int retval;
+       int ret;
        struct ide_atapi_pc pc;
 
        if (tape->chrdev_dir == IDETAPE_DIR_READ)
                __ide_tape_discard_merge_buffer(drive);
        idetape_wait_ready(drive, 60 * 5 * HZ);
        idetape_create_locate_cmd(drive, &pc, block, partition, skip);
-       retval = ide_queue_pc_tail(drive, disk, &pc);
-       if (retval)
-               return (retval);
+       ret = ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
+       if (ret)
+               return ret;
 
-       idetape_create_read_position_cmd(&pc);
-       return ide_queue_pc_tail(drive, disk, &pc);
+       ret = ide_tape_read_position(drive);
+       if (ret < 0)
+               return ret;
+       return 0;
 }
 
 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
@@ -1183,7 +827,7 @@ static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
 
        __ide_tape_discard_merge_buffer(drive);
        if (restore_position) {
-               position = idetape_read_position(drive);
+               position = ide_tape_read_position(drive);
                seek = position > 0 ? position : 0;
                if (idetape_position_tape(drive, seek, 0, 0)) {
                        printk(KERN_INFO "ide-tape: %s: position_tape failed in"
@@ -1197,36 +841,45 @@ static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
  * Generate a read/write request for the block device interface and wait for it
  * to be serviced.
  */
-static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
-                                struct idetape_bh *bh)
+static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int size)
 {
        idetape_tape_t *tape = drive->driver_data;
        struct request *rq;
-       int ret, errors;
+       int ret;
+
+       ide_debug_log(IDE_DBG_FUNC, "cmd: 0x%x, size: %d", cmd, size);
 
-       debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
+       BUG_ON(cmd != REQ_IDETAPE_READ && cmd != REQ_IDETAPE_WRITE);
+       BUG_ON(size < 0 || size % tape->blk_size);
 
        rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
        rq->cmd_type = REQ_TYPE_SPECIAL;
        rq->cmd[13] = cmd;
        rq->rq_disk = tape->disk;
-       rq->special = (void *)bh;
-       rq->sector = tape->first_frame;
-       rq->nr_sectors = blocks;
-       rq->current_nr_sectors = blocks;
-       blk_execute_rq(drive->queue, tape->disk, rq, 0);
+       rq->__sector = tape->first_frame;
 
-       errors = rq->errors;
-       ret = tape->blk_size * (blocks - rq->current_nr_sectors);
-       blk_put_request(rq);
+       if (size) {
+               ret = blk_rq_map_kern(drive->queue, rq, tape->buf, size,
+                                     __GFP_WAIT);
+               if (ret)
+                       goto out_put;
+       }
 
-       if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
-               return 0;
+       blk_execute_rq(drive->queue, tape->disk, rq, 0);
 
-       if (tape->merge_bh)
-               idetape_init_merge_buffer(tape);
-       if (errors == IDETAPE_ERROR_GENERAL)
-               return -EIO;
+       /* calculate the number of transferred bytes and update buffer state */
+       size -= rq->resid_len;
+       tape->cur = tape->buf;
+       if (cmd == REQ_IDETAPE_READ)
+               tape->valid = size;
+       else
+               tape->valid = 0;
+
+       ret = size;
+       if (rq->errors == IDE_DRV_ERROR_GENERAL)
+               ret = -EIO;
+out_put:
+       blk_put_request(rq);
        return ret;
 }
 
@@ -1263,153 +916,87 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
        pc->flags |= PC_FLAG_WAIT_FOR_DSC;
 }
 
-/* Queue up a character device originated write request. */
-static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
-{
-       idetape_tape_t *tape = drive->driver_data;
-
-       debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
-
-       return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
-                                    blocks, tape->merge_bh);
-}
-
 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
-       int blocks, min;
-       struct idetape_bh *bh;
 
        if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
                printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
                                " but we are not writing.\n");
                return;
        }
-       if (tape->merge_bh_size > tape->buffer_size) {
-               printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
-               tape->merge_bh_size = tape->buffer_size;
-       }
-       if (tape->merge_bh_size) {
-               blocks = tape->merge_bh_size / tape->blk_size;
-               if (tape->merge_bh_size % tape->blk_size) {
-                       unsigned int i;
-
-                       blocks++;
-                       i = tape->blk_size - tape->merge_bh_size %
-                               tape->blk_size;
-                       bh = tape->bh->b_reqnext;
-                       while (bh) {
-                               atomic_set(&bh->b_count, 0);
-                               bh = bh->b_reqnext;
-                       }
-                       bh = tape->bh;
-                       while (i) {
-                               if (bh == NULL) {
-                                       printk(KERN_INFO "ide-tape: bug,"
-                                                        " bh NULL\n");
-                                       break;
-                               }
-                               min = min(i, (unsigned int)(bh->b_size -
-                                               atomic_read(&bh->b_count)));
-                               memset(bh->b_data + atomic_read(&bh->b_count),
-                                               0, min);
-                               atomic_add(min, &bh->b_count);
-                               i -= min;
-                               bh = bh->b_reqnext;
-                       }
-               }
-               (void) idetape_add_chrdev_write_request(drive, blocks);
-               tape->merge_bh_size = 0;
-       }
-       if (tape->merge_bh != NULL) {
-               ide_tape_kfree_buffer(tape);
-               tape->merge_bh = NULL;
+       if (tape->buf) {
+               size_t aligned = roundup(tape->valid, tape->blk_size);
+
+               memset(tape->cur, 0, aligned - tape->valid);
+               idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, aligned);
+               kfree(tape->buf);
+               tape->buf = NULL;
        }
        tape->chrdev_dir = IDETAPE_DIR_NONE;
 }
 
-static int idetape_init_read(ide_drive_t *drive)
+static int idetape_init_rw(ide_drive_t *drive, int dir)
 {
        idetape_tape_t *tape = drive->driver_data;
-       int bytes_read;
+       int rc;
 
-       /* Initialize read operation */
-       if (tape->chrdev_dir != IDETAPE_DIR_READ) {
-               if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
-                       ide_tape_flush_merge_buffer(drive);
-                       idetape_flush_tape_buffers(drive);
-               }
-               if (tape->merge_bh || tape->merge_bh_size) {
-                       printk(KERN_ERR "ide-tape: merge_bh_size should be"
-                                        " 0 now\n");
-                       tape->merge_bh_size = 0;
-               }
-               tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
-               if (!tape->merge_bh)
-                       return -ENOMEM;
-               tape->chrdev_dir = IDETAPE_DIR_READ;
+       BUG_ON(dir != IDETAPE_DIR_READ && dir != IDETAPE_DIR_WRITE);
 
-               /*
-                * Issue a read 0 command to ensure that DSC handshake is
-                * switched from completion mode to buffer available mode.
-                * No point in issuing this if DSC overlap isn't supported, some
-                * drives (Seagate STT3401A) will return an error.
-                */
-               if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
-                       bytes_read = idetape_queue_rw_tail(drive,
-                                                       REQ_IDETAPE_READ, 0,
-                                                       tape->merge_bh);
-                       if (bytes_read < 0) {
-                               ide_tape_kfree_buffer(tape);
-                               tape->merge_bh = NULL;
-                               tape->chrdev_dir = IDETAPE_DIR_NONE;
-                               return bytes_read;
-                       }
-               }
-       }
-
-       return 0;
-}
+       if (tape->chrdev_dir == dir)
+               return 0;
 
-/* called from idetape_chrdev_read() to service a chrdev read request. */
-static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
-{
-       idetape_tape_t *tape = drive->driver_data;
+       if (tape->chrdev_dir == IDETAPE_DIR_READ)
+               ide_tape_discard_merge_buffer(drive, 1);
+       else if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
+               ide_tape_flush_merge_buffer(drive);
+               idetape_flush_tape_buffers(drive);
+       }
 
-       debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
+       if (tape->buf || tape->valid) {
+               printk(KERN_ERR "ide-tape: valid should be 0 now\n");
+               tape->valid = 0;
+       }
 
-       /* If we are at a filemark, return a read length of 0 */
-       if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
-               return 0;
+       tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL);
+       if (!tape->buf)
+               return -ENOMEM;
+       tape->chrdev_dir = dir;
+       tape->cur = tape->buf;
 
-       idetape_init_read(drive);
+       /*
+        * Issue a 0 rw command to ensure that DSC handshake is
+        * switched from completion mode to buffer available mode.  No
+        * point in issuing this if DSC overlap isn't supported, some
+        * drives (Seagate STT3401A) will return an error.
+        */
+       if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
+               int cmd = dir == IDETAPE_DIR_READ ? REQ_IDETAPE_READ
+                                                 : REQ_IDETAPE_WRITE;
+
+               rc = idetape_queue_rw_tail(drive, cmd, 0);
+               if (rc < 0) {
+                       kfree(tape->buf);
+                       tape->buf = NULL;
+                       tape->chrdev_dir = IDETAPE_DIR_NONE;
+                       return rc;
+               }
+       }
 
-       return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
-                                    tape->merge_bh);
+       return 0;
 }
 
 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
 {
        idetape_tape_t *tape = drive->driver_data;
-       struct idetape_bh *bh;
-       int blocks;
+
+       memset(tape->buf, 0, tape->buffer_size);
 
        while (bcount) {
-               unsigned int count;
+               unsigned int count = min(tape->buffer_size, bcount);
 
-               bh = tape->merge_bh;
-               count = min(tape->buffer_size, bcount);
+               idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, count);
                bcount -= count;
-               blocks = count / tape->blk_size;
-               while (count) {
-                       atomic_set(&bh->b_count,
-                                  min(count, (unsigned int)bh->b_size));
-                       memset(bh->b_data, 0, atomic_read(&bh->b_count));
-                       count -= atomic_read(&bh->b_count);
-                       bh = bh->b_reqnext;
-               }
-               idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
-                                     tape->merge_bh);
        }
 }
 
@@ -1421,20 +1008,19 @@ static int idetape_rewind_tape(ide_drive_t *drive)
 {
        struct ide_tape_obj *tape = drive->driver_data;
        struct gendisk *disk = tape->disk;
-       int retval;
        struct ide_atapi_pc pc;
+       int ret;
 
-       debug_log(DBG_SENSE, "Enter %s\n", __func__);
+       ide_debug_log(IDE_DBG_FUNC, "enter");
 
        idetape_create_rewind_cmd(drive, &pc);
-       retval = ide_queue_pc_tail(drive, disk, &pc);
-       if (retval)
-               return retval;
+       ret = ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
+       if (ret)
+               return ret;
 
-       idetape_create_read_position_cmd(&pc);
-       retval = ide_queue_pc_tail(drive, disk, &pc);
-       if (retval)
-               return retval;
+       ret = ide_tape_read_position(drive);
+       if (ret < 0)
+               return ret;
        return 0;
 }
 
@@ -1451,7 +1037,7 @@ static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
                int nr_stages;
        } config;
 
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
+       ide_debug_log(IDE_DBG_FUNC, "cmd: 0x%04x", cmd);
 
        switch (cmd) {
        case 0x0340:
@@ -1460,6 +1046,7 @@ static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
                tape->best_dsc_rw_freq = config.dsc_rw_frequency;
                break;
        case 0x0350:
+               memset(&config, 0, sizeof(config));
                config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
                config.nr_stages = 1;
                if (copy_to_user(argp, &config, sizeof(config)))
@@ -1480,6 +1067,9 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
        int retval, count = 0;
        int sprev = !!(tape->caps[4] & 0x20);
 
+
+       ide_debug_log(IDE_DBG_FUNC, "mt_op: %d, mt_count: %d", mt_op, mt_count);
+
        if (mt_count == 0)
                return 0;
        if (MTBSF == mt_op || MTBSFM == mt_op) {
@@ -1489,8 +1079,9 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
        }
 
        if (tape->chrdev_dir == IDETAPE_DIR_READ) {
-               tape->merge_bh_size = 0;
-               if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
+               tape->valid = 0;
+               if (test_and_clear_bit(ilog2(IDE_AFLAG_FILEMARK),
+                                      &drive->atapi_flags))
                        ++count;
                ide_tape_discard_merge_buffer(drive, 0);
        }
@@ -1500,7 +1091,7 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
        case MTBSF:
                idetape_create_space_cmd(&pc, mt_count - count,
                                         IDETAPE_SPACE_OVER_FILEMARK);
-               return ide_queue_pc_tail(drive, disk, &pc);
+               return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
        case MTFSFM:
        case MTBSFM:
                if (!sprev)
@@ -1538,61 +1129,54 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
 {
        struct ide_tape_obj *tape = file->private_data;
        ide_drive_t *drive = tape->drive;
-       ssize_t bytes_read, temp, actually_read = 0, rc;
+       size_t done = 0;
        ssize_t ret = 0;
-       u16 ctl = *(u16 *)&tape->caps[12];
+       int rc;
 
-       debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
+       ide_debug_log(IDE_DBG_FUNC, "count %Zd", count);
 
        if (tape->chrdev_dir != IDETAPE_DIR_READ) {
-               if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
+               if (test_bit(ilog2(IDE_AFLAG_DETECT_BS), &drive->atapi_flags))
                        if (count > tape->blk_size &&
                            (count % tape->blk_size) == 0)
                                tape->user_bs_factor = count / tape->blk_size;
        }
-       rc = idetape_init_read(drive);
+
+       rc = idetape_init_rw(drive, IDETAPE_DIR_READ);
        if (rc < 0)
                return rc;
-       if (count == 0)
-               return (0);
-       if (tape->merge_bh_size) {
-               actually_read = min((unsigned int)(tape->merge_bh_size),
-                                   (unsigned int)count);
-               if (idetape_copy_stage_to_user(tape, buf, actually_read))
-                       ret = -EFAULT;
-               buf += actually_read;
-               tape->merge_bh_size -= actually_read;
-               count -= actually_read;
-       }
-       while (count >= tape->buffer_size) {
-               bytes_read = idetape_add_chrdev_read_request(drive, ctl);
-               if (bytes_read <= 0)
-                       goto finish;
-               if (idetape_copy_stage_to_user(tape, buf, bytes_read))
-                       ret = -EFAULT;
-               buf += bytes_read;
-               count -= bytes_read;
-               actually_read += bytes_read;
-       }
-       if (count) {
-               bytes_read = idetape_add_chrdev_read_request(drive, ctl);
-               if (bytes_read <= 0)
-                       goto finish;
-               temp = min((unsigned long)count, (unsigned long)bytes_read);
-               if (idetape_copy_stage_to_user(tape, buf, temp))
+
+       while (done < count) {
+               size_t todo;
+
+               /* refill if staging buffer is empty */
+               if (!tape->valid) {
+                       /* If we are at a filemark, nothing more to read */
+                       if (test_bit(ilog2(IDE_AFLAG_FILEMARK),
+                                    &drive->atapi_flags))
+                               break;
+                       /* read */
+                       if (idetape_queue_rw_tail(drive, REQ_IDETAPE_READ,
+                                                 tape->buffer_size) <= 0)
+                               break;
+               }
+
+               /* copy out */
+               todo = min_t(size_t, count - done, tape->valid);
+               if (copy_to_user(buf + done, tape->cur, todo))
                        ret = -EFAULT;
-               actually_read += temp;
-               tape->merge_bh_size = bytes_read-temp;
+
+               tape->cur += todo;
+               tape->valid -= todo;
+               done += todo;
        }
-finish:
-       if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
-               debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
 
+       if (!done && test_bit(ilog2(IDE_AFLAG_FILEMARK), &drive->atapi_flags)) {
                idetape_space_over_filemarks(drive, MTFSF, 1);
                return 0;
        }
 
-       return ret ? ret : actually_read;
+       return ret ? ret : done;
 }
 
 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
@@ -1600,91 +1184,42 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
 {
        struct ide_tape_obj *tape = file->private_data;
        ide_drive_t *drive = tape->drive;
-       ssize_t actually_written = 0;
+       size_t done = 0;
        ssize_t ret = 0;
-       u16 ctl = *(u16 *)&tape->caps[12];
+       int rc;
 
        /* The drive is write protected. */
        if (tape->write_prot)
                return -EACCES;
 
-       debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
+       ide_debug_log(IDE_DBG_FUNC, "count %Zd", count);
 
        /* Initialize write operation */
-       if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
-               if (tape->chrdev_dir == IDETAPE_DIR_READ)
-                       ide_tape_discard_merge_buffer(drive, 1);
-               if (tape->merge_bh || tape->merge_bh_size) {
-                       printk(KERN_ERR "ide-tape: merge_bh_size "
-                               "should be 0 now\n");
-                       tape->merge_bh_size = 0;
-               }
-               tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
-               if (!tape->merge_bh)
-                       return -ENOMEM;
-               tape->chrdev_dir = IDETAPE_DIR_WRITE;
-               idetape_init_merge_buffer(tape);
+       rc = idetape_init_rw(drive, IDETAPE_DIR_WRITE);
+       if (rc < 0)
+               return rc;
 
-               /*
-                * Issue a write 0 command to ensure that DSC handshake is
-                * switched from completion mode to buffer available mode. No
-                * point in issuing this if DSC overlap isn't supported, some
-                * drives (Seagate STT3401A) will return an error.
-                */
-               if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
-                       ssize_t retval = idetape_queue_rw_tail(drive,
-                                                       REQ_IDETAPE_WRITE, 0,
-                                                       tape->merge_bh);
-                       if (retval < 0) {
-                               ide_tape_kfree_buffer(tape);
-                               tape->merge_bh = NULL;
-                               tape->chrdev_dir = IDETAPE_DIR_NONE;
-                               return retval;
-                       }
-               }
-       }
-       if (count == 0)
-               return (0);
-       if (tape->merge_bh_size) {
-               if (tape->merge_bh_size >= tape->buffer_size) {
-                       printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
-                       tape->merge_bh_size = 0;
-               }
-               actually_written = min((unsigned int)
-                               (tape->buffer_size - tape->merge_bh_size),
-                               (unsigned int)count);
-               if (idetape_copy_stage_from_user(tape, buf, actually_written))
-                               ret = -EFAULT;
-               buf += actually_written;
-               tape->merge_bh_size += actually_written;
-               count -= actually_written;
-
-               if (tape->merge_bh_size == tape->buffer_size) {
-                       ssize_t retval;
-                       tape->merge_bh_size = 0;
-                       retval = idetape_add_chrdev_write_request(drive, ctl);
-                       if (retval <= 0)
-                               return (retval);
-               }
-       }
-       while (count >= tape->buffer_size) {
-               ssize_t retval;
-               if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
-                       ret = -EFAULT;
-               buf += tape->buffer_size;
-               count -= tape->buffer_size;
-               retval = idetape_add_chrdev_write_request(drive, ctl);
-               actually_written += tape->buffer_size;
-               if (retval <= 0)
-                       return (retval);
-       }
-       if (count) {
-               actually_written += count;
-               if (idetape_copy_stage_from_user(tape, buf, count))
+       while (done < count) {
+               size_t todo;
+
+               /* flush if staging buffer is full */
+               if (tape->valid == tape->buffer_size &&
+                   idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
+                                         tape->buffer_size) <= 0)
+                       return rc;
+
+               /* copy in */
+               todo = min_t(size_t, count - done,
+                            tape->buffer_size - tape->valid);
+               if (copy_from_user(tape->cur, buf + done, todo))
                        ret = -EFAULT;
-               tape->merge_bh_size += count;
+
+               tape->cur += todo;
+               tape->valid += todo;
+               done += todo;
        }
-       return ret ? ret : actually_written;
+
+       return ret ? ret : done;
 }
 
 static int idetape_write_filemark(ide_drive_t *drive)
@@ -1694,7 +1229,7 @@ static int idetape_write_filemark(ide_drive_t *drive)
 
        /* Write a filemark */
        idetape_create_write_filemark_cmd(drive, &pc, 1);
-       if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
+       if (ide_queue_pc_tail(drive, tape->disk, &pc, NULL, 0)) {
                printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
                return -EIO;
        }
@@ -1721,8 +1256,8 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
        struct ide_atapi_pc pc;
        int i, retval;
 
-       debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
-                       mt_op, mt_count);
+       ide_debug_log(IDE_DBG_FUNC, "MTIOCTOP ioctl: mt_op: %d, mt_count: %d",
+                     mt_op, mt_count);
 
        switch (mt_op) {
        case MTFSF:
@@ -1768,7 +1303,8 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
                ide_tape_discard_merge_buffer(drive, 0);
                retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
                if (!retval)
-                       clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
+                       clear_bit(ilog2(IDE_AFLAG_MEDIUM_PRESENT),
+                                 &drive->atapi_flags);
                return retval;
        case MTNOP:
                ide_tape_discard_merge_buffer(drive, 0);
@@ -1779,20 +1315,22 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
                        IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
        case MTEOM:
                idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
-               return ide_queue_pc_tail(drive, disk, &pc);
+               return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
        case MTERASE:
                (void)idetape_rewind_tape(drive);
                idetape_create_erase_cmd(&pc);
-               return ide_queue_pc_tail(drive, disk, &pc);
+               return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
        case MTSETBLK:
                if (mt_count) {
                        if (mt_count < tape->blk_size ||
                            mt_count % tape->blk_size)
                                return -EIO;
                        tape->user_bs_factor = mt_count / tape->blk_size;
-                       clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
+                       clear_bit(ilog2(IDE_AFLAG_DETECT_BS),
+                                 &drive->atapi_flags);
                } else
-                       set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
+                       set_bit(ilog2(IDE_AFLAG_DETECT_BS),
+                               &drive->atapi_flags);
                return 0;
        case MTSEEK:
                ide_tape_discard_merge_buffer(drive, 0);
@@ -1827,7 +1365,7 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
  * supported here, and not in the corresponding block interface. Our own
  * ide-tape ioctls are supported on both interfaces.
  */
-static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
+static long do_idetape_chrdev_ioctl(struct file *file,
                                unsigned int cmd, unsigned long arg)
 {
        struct ide_tape_obj *tape = file->private_data;
@@ -1838,16 +1376,16 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
        int block_offset = 0, position = tape->first_frame;
        void __user *argp = (void __user *)arg;
 
-       debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
+       ide_debug_log(IDE_DBG_FUNC, "cmd: 0x%x", cmd);
 
        if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
                ide_tape_flush_merge_buffer(drive);
                idetape_flush_tape_buffers(drive);
        }
        if (cmd == MTIOCGET || cmd == MTIOCPOS) {
-               block_offset = tape->merge_bh_size /
+               block_offset = tape->valid /
                        (tape->blk_size * tape->user_bs_factor);
-               position = idetape_read_position(drive);
+               position = ide_tape_read_position(drive);
                if (position < 0)
                        return -EIO;
        }
@@ -1882,6 +1420,16 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
        }
 }
 
+static long idetape_chrdev_ioctl(struct file *file,
+                               unsigned int cmd, unsigned long arg)
+{
+       long ret;
+       lock_kernel();
+       ret = do_idetape_chrdev_ioctl(file, cmd, arg);
+       unlock_kernel();
+       return ret;
+}
+
 /*
  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
  * block size with the reported value.
@@ -1890,9 +1438,10 @@ static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
        struct ide_atapi_pc pc;
+       u8 buf[12];
 
        idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
-       if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
+       if (ide_queue_pc_tail(drive, tape->disk, &pc, buf, pc.req_xfer)) {
                printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
                if (tape->blk_size == 0) {
                        printk(KERN_WARNING "ide-tape: Cannot deal with zero "
@@ -1901,10 +1450,13 @@ static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
                }
                return;
        }
-       tape->blk_size = (pc.buf[4 + 5] << 16) +
-                               (pc.buf[4 + 6] << 8)  +
-                                pc.buf[4 + 7];
-       tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
+       tape->blk_size = (buf[4 + 5] << 16) +
+                               (buf[4 + 6] << 8)  +
+                                buf[4 + 7];
+       tape->drv_write_prot = (buf[2] & 0x80) >> 7;
+
+       ide_debug_log(IDE_DBG_FUNC, "blk_size: %d, write_prot: %d",
+                     tape->blk_size, tape->drv_write_prot);
 }
 
 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
@@ -1917,14 +1469,18 @@ static int idetape_chrdev_open(struct inode *inode, struct file *filp)
        if (i >= MAX_HWIFS * MAX_DRIVES)
                return -ENXIO;
 
-       lock_kernel();
-       tape = ide_tape_chrdev_get(i);
+       mutex_lock(&idetape_chrdev_mutex);
+
+       tape = ide_tape_get(NULL, true, i);
        if (!tape) {
-               unlock_kernel();
+               mutex_unlock(&idetape_chrdev_mutex);
                return -ENXIO;
        }
 
-       debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
+       drive = tape->drive;
+       filp->private_data = tape;
+
+       ide_debug_log(IDE_DBG_FUNC, "enter");
 
        /*
         * We really want to do nonseekable_open(inode, filp); here, but some
@@ -1933,24 +1489,21 @@ static int idetape_chrdev_open(struct inode *inode, struct file *filp)
         */
        filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
 
-       drive = tape->drive;
-
-       filp->private_data = tape;
 
-       if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
+       if (test_and_set_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags)) {
                retval = -EBUSY;
                goto out_put_tape;
        }
 
        retval = idetape_wait_ready(drive, 60 * HZ);
        if (retval) {
-               clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
+               clear_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags);
                printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
                goto out_put_tape;
        }
 
-       idetape_read_position(drive);
-       if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
+       ide_tape_read_position(drive);
+       if (!test_bit(ilog2(IDE_AFLAG_ADDRESS_VALID), &drive->atapi_flags))
                (void)idetape_rewind_tape(drive);
 
        /* Read block size and write protect status from drive. */
@@ -1966,7 +1519,7 @@ static int idetape_chrdev_open(struct inode *inode, struct file *filp)
        if (tape->write_prot) {
                if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
                    (filp->f_flags & O_ACCMODE) == O_RDWR) {
-                       clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
+                       clear_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags);
                        retval = -EROFS;
                        goto out_put_tape;
                }
@@ -1979,12 +1532,15 @@ static int idetape_chrdev_open(struct inode *inode, struct file *filp)
                                tape->door_locked = DOOR_LOCKED;
                }
        }
-       unlock_kernel();
+       mutex_unlock(&idetape_chrdev_mutex);
+
        return 0;
 
 out_put_tape:
        ide_tape_put(tape);
-       unlock_kernel();
+
+       mutex_unlock(&idetape_chrdev_mutex);
+
        return retval;
 }
 
@@ -1993,12 +1549,12 @@ static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
        idetape_tape_t *tape = drive->driver_data;
 
        ide_tape_flush_merge_buffer(drive);
-       tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
-       if (tape->merge_bh != NULL) {
+       tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL);
+       if (tape->buf != NULL) {
                idetape_pad_zeros(drive, tape->blk_size *
                                (tape->user_bs_factor - 1));
-               ide_tape_kfree_buffer(tape);
-               tape->merge_bh = NULL;
+               kfree(tape->buf);
+               tape->buf = NULL;
        }
        idetape_write_filemark(drive);
        idetape_flush_tape_buffers(drive);
@@ -2011,10 +1567,11 @@ static int idetape_chrdev_release(struct inode *inode, struct file *filp)
        ide_drive_t *drive = tape->drive;
        unsigned int minor = iminor(inode);
 
-       lock_kernel();
+       mutex_lock(&idetape_chrdev_mutex);
+
        tape = drive->driver_data;
 
-       debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
+       ide_debug_log(IDE_DBG_FUNC, "enter");
 
        if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
                idetape_write_release(drive, minor);
@@ -2023,17 +1580,21 @@ static int idetape_chrdev_release(struct inode *inode, struct file *filp)
                        ide_tape_discard_merge_buffer(drive, 1);
        }
 
-       if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
+       if (minor < 128 && test_bit(ilog2(IDE_AFLAG_MEDIUM_PRESENT),
+                                   &drive->atapi_flags))
                (void) idetape_rewind_tape(drive);
+
        if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
                if (tape->door_locked == DOOR_LOCKED) {
                        if (!ide_set_media_lock(drive, tape->disk, 0))
                                tape->door_locked = DOOR_UNLOCKED;
                }
        }
-       clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
+       clear_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags);
        ide_tape_put(tape);
-       unlock_kernel();
+
+       mutex_unlock(&idetape_chrdev_mutex);
+
        return 0;
 }
 
@@ -2041,17 +1602,18 @@ static void idetape_get_inquiry_results(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
        struct ide_atapi_pc pc;
+       u8 pc_buf[256];
        char fw_rev[4], vendor_id[8], product_id[16];
 
        idetape_create_inquiry_cmd(&pc);
-       if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
+       if (ide_queue_pc_tail(drive, tape->disk, &pc, pc_buf, pc.req_xfer)) {
                printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
                                tape->name);
                return;
        }
-       memcpy(vendor_id, &pc.buf[8], 8);
-       memcpy(product_id, &pc.buf[16], 16);
-       memcpy(fw_rev, &pc.buf[32], 4);
+       memcpy(vendor_id, &pc_buf[8], 8);
+       memcpy(product_id, &pc_buf[16], 16);
+       memcpy(fw_rev, &pc_buf[32], 4);
 
        ide_fixstring(vendor_id, 8, 0);
        ide_fixstring(product_id, 16, 0);
@@ -2069,11 +1631,11 @@ static void idetape_get_mode_sense_results(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
        struct ide_atapi_pc pc;
-       u8 *caps;
+       u8 buf[24], *caps;
        u8 speed, max_speed;
 
        idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
-       if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
+       if (ide_queue_pc_tail(drive, tape->disk, &pc, buf, pc.req_xfer)) {
                printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
                                " some default values\n");
                tape->blk_size = 512;
@@ -2082,7 +1644,7 @@ static void idetape_get_mode_sense_results(ide_drive_t *drive)
                put_unaligned(6*52, (u16 *)&tape->caps[16]);
                return;
        }
-       caps = pc.buf + 4 + pc.buf[3];
+       caps = buf + 4 + buf[3];
 
        /* convert to host order and save for later use */
        speed = be16_to_cpup((__be16 *)&caps[14]);
@@ -2148,7 +1710,6 @@ static int divf_buffer_size(ide_drive_t *drive)   { return 1024; }
 
 ide_devset_rw_flag(dsc_overlap, IDE_DFLAG_DSC_OVERLAP);
 
-ide_tape_devset_rw_field(debug_mask, debug_mask);
 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
 
 ide_tape_devset_r_field(avg_speed, avg_speed);
@@ -2160,12 +1721,11 @@ static const struct ide_proc_devset idetape_settings[] = {
        __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
        __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
        __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
-       __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
        __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
        __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
        __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
                                        mulf_tdsc, divf_tdsc),
-       { 0 },
+       { NULL },
 };
 #endif
 
@@ -2187,11 +1747,9 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
        int buffer_size;
        u16 *ctl = (u16 *)&tape->caps[12];
 
-       drive->pc_callback       = ide_tape_callback;
-       drive->pc_update_buffers = idetape_update_buffers;
-       drive->pc_io_buffers     = ide_tape_io_buffers;
+       ide_debug_log(IDE_DBG_FUNC, "minor: %d", minor);
 
-       spin_lock_init(&tape->lock);
+       drive->pc_callback = ide_tape_callback;
 
        drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;
 
@@ -2222,11 +1780,6 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
                tape->buffer_size = *ctl * tape->blk_size;
        }
        buffer_size = tape->buffer_size;
-       tape->pages_per_buffer = buffer_size / PAGE_SIZE;
-       if (buffer_size % PAGE_SIZE) {
-               tape->pages_per_buffer++;
-               tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
-       }
 
        /* select the "best" DSC read/write polling freq */
        speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
@@ -2255,19 +1808,21 @@ static void ide_tape_remove(ide_drive_t *drive)
        idetape_tape_t *tape = drive->driver_data;
 
        ide_proc_unregister_driver(drive, tape->driver);
-
+       device_del(&tape->dev);
        ide_unregister_region(tape->disk);
 
-       ide_tape_put(tape);
+       mutex_lock(&idetape_ref_mutex);
+       put_device(&tape->dev);
+       mutex_unlock(&idetape_ref_mutex);
 }
 
-static void ide_tape_release(struct kref *kref)
+static void ide_tape_release(struct device *dev)
 {
-       struct ide_tape_obj *tape = to_ide_drv(kref, ide_tape_obj);
+       struct ide_tape_obj *tape = to_ide_drv(dev, ide_tape_obj);
        ide_drive_t *drive = tape->drive;
        struct gendisk *g = tape->disk;
 
-       BUG_ON(tape->merge_bh_size);
+       BUG_ON(tape->valid);
 
        drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
        drive->driver_data = NULL;
@@ -2281,28 +1836,48 @@ static void ide_tape_release(struct kref *kref)
 }
 
 #ifdef CONFIG_IDE_PROC_FS
-static int proc_idetape_read_name
-       (char *page, char **start, off_t off, int count, int *eof, void *data)
+static int idetape_name_proc_show(struct seq_file *m, void *v)
 {
-       ide_drive_t     *drive = (ide_drive_t *) data;
+       ide_drive_t     *drive = (ide_drive_t *) m->private;
        idetape_tape_t  *tape = drive->driver_data;
-       char            *out = page;
-       int             len;
 
-       len = sprintf(out, "%s\n", tape->name);
-       PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
+       seq_printf(m, "%s\n", tape->name);
+       return 0;
+}
+
+static int idetape_name_proc_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, idetape_name_proc_show, PDE(inode)->data);
 }
 
+static const struct file_operations idetape_name_proc_fops = {
+       .owner          = THIS_MODULE,
+       .open           = idetape_name_proc_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = single_release,
+};
+
 static ide_proc_entry_t idetape_proc[] = {
-       { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
-       { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
-       { NULL, 0, NULL, NULL }
+       { "capacity",   S_IFREG|S_IRUGO,        &ide_capacity_proc_fops },
+       { "name",       S_IFREG|S_IRUGO,        &idetape_name_proc_fops },
+       {}
 };
+
+static ide_proc_entry_t *ide_tape_proc_entries(ide_drive_t *drive)
+{
+       return idetape_proc;
+}
+
+static const struct ide_proc_devset *ide_tape_proc_devsets(ide_drive_t *drive)
+{
+       return idetape_settings;
+}
 #endif
 
 static int ide_tape_probe(ide_drive_t *);
 
-static ide_driver_t idetape_driver = {
+static struct ide_driver idetape_driver = {
        .gen_driver = {
                .owner          = THIS_MODULE,
                .name           = "ide-tape",
@@ -2312,11 +1887,9 @@ static ide_driver_t idetape_driver = {
        .remove                 = ide_tape_remove,
        .version                = IDETAPE_VERSION,
        .do_request             = idetape_do_request,
-       .end_request            = idetape_end_request,
-       .error                  = __ide_error,
 #ifdef CONFIG_IDE_PROC_FS
-       .proc                   = idetape_proc,
-       .settings               = idetape_settings,
+       .proc_entries           = ide_tape_proc_entries,
+       .proc_devsets           = ide_tape_proc_devsets,
 #endif
 };
 
@@ -2325,50 +1898,45 @@ static const struct file_operations idetape_fops = {
        .owner          = THIS_MODULE,
        .read           = idetape_chrdev_read,
        .write          = idetape_chrdev_write,
-       .ioctl          = idetape_chrdev_ioctl,
+       .unlocked_ioctl = idetape_chrdev_ioctl,
        .open           = idetape_chrdev_open,
        .release        = idetape_chrdev_release,
 };
 
-static int idetape_open(struct inode *inode, struct file *filp)
+static int idetape_open(struct block_device *bdev, fmode_t mode)
 {
-       struct gendisk *disk = inode->i_bdev->bd_disk;
-       struct ide_tape_obj *tape;
+       struct ide_tape_obj *tape = ide_tape_get(bdev->bd_disk, false, 0);
 
-       tape = ide_tape_get(disk);
        if (!tape)
                return -ENXIO;
 
        return 0;
 }
 
-static int idetape_release(struct inode *inode, struct file *filp)
+static int idetape_release(struct gendisk *disk, fmode_t mode)
 {
-       struct gendisk *disk = inode->i_bdev->bd_disk;
        struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);
 
        ide_tape_put(tape);
-
        return 0;
 }
 
-static int idetape_ioctl(struct inode *inode, struct file *file,
+static int idetape_ioctl(struct block_device *bdev, fmode_t mode,
                        unsigned int cmd, unsigned long arg)
 {
-       struct block_device *bdev = inode->i_bdev;
        struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);
        ide_drive_t *drive = tape->drive;
-       int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
+       int err = generic_ide_ioctl(drive, bdev, cmd, arg);
        if (err == -EINVAL)
                err = idetape_blkdev_ioctl(drive, cmd, arg);
        return err;
 }
 
-static struct block_device_operations idetape_block_ops = {
+static const struct block_device_operations idetape_block_ops = {
        .owner          = THIS_MODULE,
        .open           = idetape_open,
        .release        = idetape_release,
-       .ioctl          = idetape_ioctl,
+       .locked_ioctl   = idetape_ioctl,
 };
 
 static int ide_tape_probe(ide_drive_t *drive)
@@ -2377,7 +1945,9 @@ static int ide_tape_probe(ide_drive_t *drive)
        struct gendisk *g;
        int minor;
 
-       if (!strstr("ide-tape", drive->driver_req))
+       ide_debug_log(IDE_DBG_FUNC, "enter");
+
+       if (!strstr(DRV_NAME, drive->driver_req))
                goto failed;
 
        if (drive->media != ide_tape)
@@ -2402,7 +1972,12 @@ static int ide_tape_probe(ide_drive_t *drive)
 
        ide_init_disk(g, drive);
 
-       kref_init(&tape->kref);
+       tape->dev.parent = &drive->gendev;
+       tape->dev.release = ide_tape_release;
+       dev_set_name(&tape->dev, dev_name(&drive->gendev));
+
+       if (device_register(&tape->dev))
+               goto out_free_disk;
 
        tape->drive = drive;
        tape->driver = &idetape_driver;
@@ -2431,6 +2006,8 @@ static int ide_tape_probe(ide_drive_t *drive)
 
        return 0;
 
+out_free_disk:
+       put_disk(g);
 out_free_tape:
        kfree(tape);
 failed: