From e998f30b45efb99a3c3ce7b5483f76317a17abed Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 19 Apr 2009 08:46:02 +0900 Subject: [PATCH] ide-tape: use standard data transfer mechanism Impact: use standard way to transfer data ide-tape uses rq in an interesting way. For r/w requests, rq->special is used to carry a private buffer management structure idetape_bh and rq->nr_sectors and current_nr_sectors are initialized to the number of idetape blocks which isn't necessary 512 bytes. Also, rq->current_nr_sectors is used to report back the residual count in units of idetape blocks. This peculiarity taxes both block layer and ide. ide-atapi has different paths and hooks to accomodate it and what a rq means becomes quite confusing and making changes at the block layer becomes quite difficult and error-prone. This patch makes ide-tape use bio instead. With the previous patch, ide-tape currently is using single contiguos buffer so replacing it isn't difficult. Data buffer is mapped into bio using blk_rq_map_kern() in idetape_queue_rw_tail(). idetape_io_buffers() and idetape_update_buffers() are dropped and pc->bh is set to null to tell ide-atapi to use standard data transfer mechanism and idetape_bh byte counts are updated by the issuer on completion using the residual count. This change also nicely removes the FIXME in ide_pc_intr() where ide-tape rqs need to be completed using ide_rq_bytes() instead of blk_rq_bytes() (although this didn't really matter as the request didn't have bio). Signed-off-by: Tejun Heo Cc: Jens Axboe --- drivers/ide/ide-atapi.c | 6 +-- drivers/ide/ide-tape.c | 112 ++++++++++-------------------------------------- 2 files changed, 24 insertions(+), 94 deletions(-) diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c index 3df5442..b9dd450 100644 --- a/drivers/ide/ide-atapi.c +++ b/drivers/ide/ide-atapi.c @@ -413,11 +413,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive) * ->pc_callback() might change rq->data_len for * residual count, cache total length. */ - if (!blk_special_request(rq) && - (drive->media == ide_tape && !rq->bio)) - done = ide_rq_bytes(rq); /* FIXME */ - else - done = blk_rq_bytes(rq); + done = blk_rq_bytes(rq); /* Command finished - Call the callback function */ uptodate = drive->pc_callback(drive, dsc); diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c index b2afbc7..b373ac8 100644 --- a/drivers/ide/ide-tape.c +++ b/drivers/ide/ide-tape.c @@ -292,65 +292,6 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i) return tape; } -static int idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc, - unsigned int bcount) -{ - struct idetape_bh *bh = pc->bh; - int count; - - if (bcount && bh) { - 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) - pc->bh = NULL; - } - - return bcount; -} - -static int idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc, - unsigned int bcount) -{ - struct idetape_bh *bh = pc->bh; - int count; - - if (bcount && bh) { - 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) - pc->bh = NULL; - } - - return bcount; -} - -static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc) -{ - struct idetape_bh *bh = pc->bh; - unsigned int bcount = pc->xferred; - - if (pc->flags & PC_FLAG_WRITING) - return; - if (bcount) { - if (bh == NULL || bcount > bh->b_size) { - printk(KERN_ERR "ide-tape: bh == NULL in %s\n", - __func__); - return; - } - atomic_set(&bh->b_count, bcount); - if (atomic_read(&bh->b_count) == bh->b_size) - pc->bh = NULL; - } -} - /* * called on each failed packet command retry to analyze the request sense. We * currently do not utilize this information. @@ -368,12 +309,10 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense) pc->c[0], tape->sense_key, tape->asc, tape->ascq); /* Correct pc->xferred by asking the tape. */ - if (pc->flags & PC_FLAG_DMA_ERROR) { + 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); - } /* * If error was the result of a zero-length read or write command, @@ -458,7 +397,7 @@ static int ide_tape_callback(ide_drive_t *drive, int dsc) } tape->first_frame += blocks; - rq->current_nr_sectors -= blocks; + rq->data_len -= blocks * tape->blk_size; if (pc->error) { uptodate = 0; @@ -520,19 +459,6 @@ static void ide_tape_handle_dsc(ide_drive_t *drive) idetape_postpone_request(drive); } -static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc, - unsigned int bcount, int write) -{ - unsigned int bleft; - - if (write) - bleft = idetape_output_buffers(drive, pc, bcount); - else - bleft = idetape_input_buffers(drive, pc, bcount); - - return bcount - bleft; -} - /* * Packet Command Interface * @@ -683,7 +609,7 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape, ide_init_pc(pc); put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]); pc->c[1] = 1; - pc->bh = bh; + pc->bh = NULL; pc->buf = NULL; pc->buf_size = length * tape->blk_size; pc->req_xfer = pc->buf_size; @@ -1063,10 +989,12 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh) { idetape_tape_t *tape = drive->driver_data; + size_t size = blocks * tape->blk_size; struct request *rq; - int ret, errors; + int ret; debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd); + BUG_ON(cmd != REQ_IDETAPE_READ && cmd != REQ_IDETAPE_WRITE); rq = blk_get_request(drive->queue, READ, __GFP_WAIT); rq->cmd_type = REQ_TYPE_SPECIAL; @@ -1074,21 +1002,29 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, rq->rq_disk = tape->disk; rq->special = (void *)bh; rq->sector = tape->first_frame; - rq->nr_sectors = blocks; - rq->current_nr_sectors = blocks; + + if (size) { + ret = blk_rq_map_kern(drive->queue, rq, bh->b_data, size, + __GFP_WAIT); + if (ret) + goto out_put; + } + blk_execute_rq(drive->queue, tape->disk, rq, 0); - errors = rq->errors; - ret = tape->blk_size * (blocks - rq->current_nr_sectors); - blk_put_request(rq); + /* calculate the number of transferred bytes and update bh */ + size -= rq->data_len; + if (cmd == REQ_IDETAPE_READ) + atomic_add(size, &bh->b_count); - if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0) - return 0; + ret = size; + if (rq->errors == IDE_DRV_ERROR_GENERAL) + ret = -EIO; if (tape->merge_bh) idetape_init_merge_buffer(tape); - if (errors == IDE_DRV_ERROR_GENERAL) - return -EIO; +out_put: + blk_put_request(rq); return ret; } @@ -2034,8 +1970,6 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor) 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; drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP; -- 1.8.2.3