X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=drivers%2Fide%2Fide-tape.c;h=6a0e625421675a26eba76632ec8127d84eacfbeb;hb=d41a5b7da223f7a80844fb3e948e8d5e6181f214;hp=2c235401aad1606b8399518da2ec888cf83c472d;hpb=5aeddf907f149cae7e19b7c23ccea3823d00698c;p=safe%2Fjmp%2Flinux-2.6

diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 2c23540..6a0e625 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -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>
@@ -47,28 +48,13 @@
 #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 *idetape_devs[MAX_HWIFS * MAX_DRIVES];
 
-static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
+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);
@@ -788,55 +570,39 @@ 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.
 	 */
 	stat = hwif->tp_ops->read_status(hwif);
 
-	if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
-		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
+	if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
+	    (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
+		drive->atapi_flags |= IDE_AFLAG_IGNORE_DSC;
 
-	if (drive->post_reset == 1) {
-		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
-		drive->post_reset = 0;
+	if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
+		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;
@@ -853,9 +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);
@@ -867,7 +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;
@@ -879,167 +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);
 }
 
 /*
@@ -1062,7 +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)
@@ -1090,33 +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];
 
-	debug_log(DBG_PROCS, "Enter %s\n", __func__);
+	ide_debug_log(IDE_DBG_FUNC, "enter");
 
-	idetape_create_read_position_cmd(&pc);
-	if (ide_queue_pc_tail(drive, tape->disk, &pc))
+	/* prep cmd */
+	ide_init_pc(&pc);
+	pc.c[0] = READ_POSITION;
+	pc.req_xfer = 20;
+
+	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,
@@ -1138,11 +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;
@@ -1159,19 +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,
@@ -1182,7 +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"
@@ -1196,36 +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;
 
-	debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
+	ide_debug_log(IDE_DBG_FUNC, "cmd: 0x%x, size: %d", cmd, size);
+
+	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;
 }
 
@@ -1262,153 +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;
-
-	/* 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;
+	int rc;
 
-		/*
-		 * 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->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;
-			}
-		}
-	}
+	BUG_ON(dir != IDETAPE_DIR_READ && dir != IDETAPE_DIR_WRITE);
 
-	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);
 	}
 }
 
@@ -1420,20 +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;
 }
 
@@ -1450,7 +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:
@@ -1459,6 +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)))
@@ -1479,6 +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) {
@@ -1488,8 +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);
 	}
@@ -1499,7 +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)
@@ -1537,61 +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,
@@ -1599,91 +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->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)
@@ -1693,7 +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;
 	}
@@ -1720,8 +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:
@@ -1767,7 +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);
@@ -1778,20 +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);
@@ -1837,16 +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;
 	}
@@ -1889,9 +1428,10 @@ 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 "
@@ -1900,10 +1440,13 @@ 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)
@@ -1916,14 +1459,18 @@ 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
@@ -1932,24 +1479,21 @@ 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. */
@@ -1965,7 +1509,7 @@ 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;
 		}
@@ -1978,12 +1522,15 @@ 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;
 }
 
@@ -1992,12 +1539,12 @@ 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);
@@ -2010,10 +1557,11 @@ 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);
@@ -2022,17 +1570,21 @@ 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;
 }
 
@@ -2040,17 +1592,18 @@ 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);
@@ -2068,11 +1621,11 @@ 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;
@@ -2081,7 +1634,7 @@ 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]);
@@ -2107,7 +1660,7 @@ static void idetape_get_mode_sense_results(ide_drive_t *drive)
 
 	/* device lacks locking support according to capabilities page */
 	if ((caps[6] & 1) == 0)
-		drive->atapi_flags |= IDE_AFLAG_NO_DOORLOCK;
+		drive->dev_flags &= ~IDE_DFLAG_DOORLOCKING;
 
 	if (caps[7] & 0x02)
 		tape->blk_size = 512;
@@ -2145,9 +1698,8 @@ static int divf_tdsc(ide_drive_t *drive)	{ return   HZ; }
 static int divf_buffer(ide_drive_t *drive)	{ return    2; }
 static int divf_buffer_size(ide_drive_t *drive)	{ return 1024; }
 
-ide_devset_rw_field(dsc_overlap, dsc_overlap);
+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);
@@ -2159,12 +1711,11 @@ 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
 
@@ -2184,35 +1735,30 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
 	unsigned long t;
 	int speed;
 	int buffer_size;
-	u8 gcw[2];
 	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);
+
+	drive->pc_callback = ide_tape_callback;
+
+	drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;
 
-	spin_lock_init(&tape->lock);
-	drive->dsc_overlap = 1;
 	if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
 		printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
 				 tape->name);
-		drive->dsc_overlap = 0;
+		drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
 	}
+
 	/* Seagate Travan drives do not support DSC overlap. */
 	if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
-		drive->dsc_overlap = 0;
+		drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
+
 	tape->minor = minor;
 	tape->name[0] = 'h';
 	tape->name[1] = 't';
 	tape->name[2] = '0' + minor;
 	tape->chrdev_dir = IDETAPE_DIR_NONE;
 
-	*((u16 *)&gcw) = drive->id[ATA_ID_CONFIG];
-
-	/* Command packet DRQ type */
-	if (((gcw[0] & 0x60) >> 5) == 1)
-		set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
-
 	idetape_get_inquiry_results(drive);
 	idetape_get_mode_sense_results(drive);
 	ide_tape_get_bsize_from_bdesc(drive);
@@ -2224,11 +1770,6 @@ 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]);
@@ -2247,7 +1788,7 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
 		(*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
 		tape->buffer_size / 1024,
 		tape->best_dsc_rw_freq * 1000 / HZ,
-		drive->using_dma ? ", DMA":"");
+		(drive->dev_flags & IDE_DFLAG_USING_DMA) ? ", DMA" : "");
 
 	ide_proc_register_driver(drive, tape->driver);
 }
@@ -2257,21 +1798,23 @@ 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->dsc_overlap = 0;
+	drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
 	drive->driver_data = NULL;
 	device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
 	device_destroy(idetape_sysfs_class,
@@ -2283,28 +1826,48 @@ 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",
@@ -2313,13 +1876,10 @@ static ide_driver_t idetape_driver = {
 	.probe			= ide_tape_probe,
 	.remove			= ide_tape_remove,
 	.version		= IDETAPE_VERSION,
-	.media			= ide_tape,
 	.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
 };
 
@@ -2333,45 +1893,40 @@ static const struct file_operations idetape_fops = {
 	.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)
@@ -2380,13 +1935,16 @@ 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)
 		goto failed;
 
-	if (drive->id_read == 1 && !ide_check_atapi_device(drive, DRV_NAME)) {
+	if ((drive->dev_flags & IDE_DFLAG_ID_READ) &&
+	    ide_check_atapi_device(drive, DRV_NAME) == 0) {
 		printk(KERN_ERR "ide-tape: %s: not supported by this version of"
 				" the driver\n", drive->name);
 		goto failed;
@@ -2404,7 +1962,12 @@ 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;
@@ -2422,18 +1985,19 @@ static int ide_tape_probe(ide_drive_t *drive)
 
 	idetape_setup(drive, tape, minor);
 
-	device_create_drvdata(idetape_sysfs_class, &drive->gendev,
-			      MKDEV(IDETAPE_MAJOR, minor), NULL,
-			      "%s", tape->name);
-	device_create_drvdata(idetape_sysfs_class, &drive->gendev,
-			      MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
-			      "n%s", tape->name);
+	device_create(idetape_sysfs_class, &drive->gendev,
+		      MKDEV(IDETAPE_MAJOR, minor), NULL, "%s", tape->name);
+	device_create(idetape_sysfs_class, &drive->gendev,
+		      MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
+		      "n%s", tape->name);
 
 	g->fops = &idetape_block_ops;
 	ide_register_region(g);
 
 	return 0;
 
+out_free_disk:
+	put_disk(g);
 out_free_tape:
 	kfree(tape);
 failed: