From 5e69bd959d1086f87a603b4ddc6bdb0a130ec7db Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sun, 27 Apr 2008 15:38:25 +0200 Subject: [PATCH] ide-tape: remove pipeline-specific code from idetape_add_chrdev_read_request() In order to do away with queueing read requests on the pipeline, several things have to be done: 1. Do not allocate additional pipeline stages in idetape_init_read() until (tape->nr_stages < max_stages) and do only read operation preparations. As a collateral result, idetape_add_stage_tail() becomes unused so remove it. 2. Queue the read request's buffer directly thru idetape_queue_rw_tail(). 3. Remove now unused idetape_kmalloc_stage() and idetape_switch_buffers(). [bart: simplify the original patch] Signed-off-by: Borislav Petkov Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/ide-tape.c | 96 +++--------------------------------------- 1 file changed, 5 insertions(+), 91 deletions(-) diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c index e785145abb47..e176b5c1b208 100644 --- a/drivers/ide/ide-tape.c +++ b/drivers/ide/ide-tape.c @@ -1586,15 +1586,6 @@ abort: return NULL; } -static idetape_stage_t *idetape_kmalloc_stage(idetape_tape_t *tape) -{ - debug_log(DBG_PROCS, "Enter %s\n", __func__); - - if (tape->nr_stages >= tape->max_stages) - return NULL; - return __idetape_kmalloc_stage(tape, 0, 0); -} - static int idetape_copy_stage_from_user(idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n) { @@ -1672,39 +1663,6 @@ static void idetape_init_merge_stage(idetape_tape_t *tape) } } -static void idetape_switch_buffers(idetape_tape_t *tape, idetape_stage_t *stage) -{ - struct idetape_bh *tmp; - - tmp = stage->bh; - stage->bh = tape->merge_stage->bh; - tape->merge_stage->bh = tmp; - idetape_init_merge_stage(tape); -} - -/* Add a new stage at the end of the pipeline. */ -static void idetape_add_stage_tail(ide_drive_t *drive, idetape_stage_t *stage) -{ - idetape_tape_t *tape = drive->driver_data; - unsigned long flags; - - debug_log(DBG_PROCS, "Enter %s\n", __func__); - - spin_lock_irqsave(&tape->lock, flags); - stage->next = NULL; - if (tape->last_stage != NULL) - tape->last_stage->next = stage; - else - tape->first_stage = stage; - tape->next_stage = stage; - tape->last_stage = stage; - if (tape->next_stage == NULL) - tape->next_stage = tape->last_stage; - tape->nr_stages++; - tape->nr_pending_stages++; - spin_unlock_irqrestore(&tape->lock, flags); -} - /* Install a completion in a pending request and sleep until it is serviced. The * caller should ensure that the request will not be serviced before we install * the completion (usually by disabling interrupts). @@ -2228,10 +2186,7 @@ static void idetape_empty_write_pipeline(ide_drive_t *drive) static int idetape_init_read(ide_drive_t *drive, int max_stages) { idetape_tape_t *tape = drive->driver_data; - idetape_stage_t *new_stage; - struct request rq; int bytes_read; - u16 blocks = *(u16 *)&tape->caps[12]; /* Initialize read operation */ if (tape->chrdev_dir != IDETAPE_DIR_READ) { @@ -2267,21 +2222,7 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages) } } } - idetape_init_rq(&rq, REQ_IDETAPE_READ); - rq.sector = tape->first_frame; - rq.nr_sectors = blocks; - rq.current_nr_sectors = blocks; - if (!test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags) && - tape->nr_stages < max_stages) { - new_stage = idetape_kmalloc_stage(tape); - while (new_stage != NULL) { - new_stage->rq = rq; - idetape_add_stage_tail(drive, new_stage); - if (tape->nr_stages >= max_stages) - break; - new_stage = idetape_kmalloc_stage(tape); - } - } + if (!test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) { if (tape->nr_pending_stages >= 3 * max_stages / 4) { tape->measure_insert_time = 1; @@ -2301,9 +2242,6 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages) static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks) { idetape_tape_t *tape = drive->driver_data; - unsigned long flags; - struct request *rq_ptr; - int bytes_read; debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks); @@ -2311,37 +2249,13 @@ static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks) if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) return 0; - /* Wait for the next block to reach the head of the pipeline. */ idetape_init_read(drive, tape->max_stages); - if (tape->first_stage == NULL) { - if (test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags)) - return 0; - return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, - tape->merge_stage->bh); - } - idetape_wait_first_stage(drive); - rq_ptr = &tape->first_stage->rq; - bytes_read = tape->blk_size * (rq_ptr->nr_sectors - - rq_ptr->current_nr_sectors); - rq_ptr->nr_sectors = 0; - rq_ptr->current_nr_sectors = 0; - if (rq_ptr->errors == IDETAPE_ERROR_EOD) + if (test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags)) return 0; - else { - idetape_switch_buffers(tape, tape->first_stage); - if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK) - set_bit(IDETAPE_FLAG_FILEMARK, &tape->flags); - spin_lock_irqsave(&tape->lock, flags); - idetape_remove_stage_head(drive); - spin_unlock_irqrestore(&tape->lock, flags); - } - if (bytes_read > blocks * tape->blk_size) { - printk(KERN_ERR "ide-tape: bug: trying to return more bytes" - " than requested\n"); - bytes_read = blocks * tape->blk_size; - } - return (bytes_read); + + return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, + tape->merge_stage->bh); } static void idetape_pad_zeros(ide_drive_t *drive, int bcount) -- 2.20.1