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ide-tape: remove remaining pipeline functionality
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The driver is using now solely its own request queue.

- tape->next_stage is always NULL so it is safe to remove
  all code depending on tape->next_stage != NULL

- this patch removes the last place which sets
  IDETAPE_FLAG_PIPELINE_ACTIVE in tape->flags

[bart: add above explanations]

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
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Borislav Petkov authored and Bartlomiej Zolnierkiewicz committed Apr 27, 2008
1 parent ea1ab3d commit 0aa4b01
Showing 1 changed file with 2 additions and 100 deletions.
102 changes: 2 additions & 100 deletions drivers/ide/ide-tape.c
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Original file line number Diff line number Diff line change
Expand Up @@ -642,28 +642,6 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
}
}

static void idetape_activate_next_stage(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
idetape_stage_t *stage = tape->next_stage;
struct request *rq = &stage->rq;

debug_log(DBG_PROCS, "Enter %s\n", __func__);

if (stage == NULL) {
printk(KERN_ERR "ide-tape: bug: Trying to activate a non"
" existing stage\n");
return;
}

rq->rq_disk = tape->disk;
rq->buffer = NULL;
rq->special = (void *)stage->bh;
tape->active_data_rq = rq;
tape->active_stage = stage;
tape->next_stage = stage->next;
}

/* Free a stage along with its related buffers completely. */
static void __idetape_kfree_stage(idetape_stage_t *stage)
{
Expand Down Expand Up @@ -1546,28 +1524,6 @@ static void idetape_init_merge_stage(idetape_tape_t *tape)
}
}

/* 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).
*/
static void idetape_wait_for_request(ide_drive_t *drive, struct request *rq)
{
DECLARE_COMPLETION_ONSTACK(wait);
idetape_tape_t *tape = drive->driver_data;

if (rq == NULL || !blk_special_request(rq)) {
printk(KERN_ERR "ide-tape: bug: Trying to sleep on non-valid"
" request\n");
return;
}
rq->end_io_data = &wait;
rq->end_io = blk_end_sync_rq;
spin_unlock_irq(&tape->lock);
wait_for_completion(&wait);
/* The stage and its struct request have been deallocated */
spin_lock_irq(&tape->lock);
}

static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
Expand Down Expand Up @@ -1782,8 +1738,6 @@ static int __idetape_discard_read_pipeline(ide_drive_t *drive)

spin_lock_irqsave(&tape->lock, flags);
tape->next_stage = NULL;
if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags))
idetape_wait_for_request(drive, tape->active_data_rq);
spin_unlock_irqrestore(&tape->lock, flags);

while (tape->first_stage != NULL) {
Expand Down Expand Up @@ -1878,19 +1832,6 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
return (tape->blk_size * (blocks-rq.current_nr_sectors));
}

/* start servicing the pipeline stages, starting from tape->next_stage. */
static void idetape_plug_pipeline(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;

if (tape->next_stage == NULL)
return;
if (!test_and_set_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
idetape_activate_next_stage(drive);
(void) ide_do_drive_cmd(drive, tape->active_data_rq, ide_end);
}
}

static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
{
idetape_init_pc(pc);
Expand Down Expand Up @@ -1932,45 +1873,11 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
{
idetape_tape_t *tape = drive->driver_data;
unsigned long flags;

debug_log(DBG_CHRDEV, "Enter %s\n", __func__);

/* Attempt to allocate a new stage. Beware possible race conditions. */
while (1) {
spin_lock_irqsave(&tape->lock, flags);
if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
idetape_wait_for_request(drive, tape->active_data_rq);
spin_unlock_irqrestore(&tape->lock, flags);
} else {
spin_unlock_irqrestore(&tape->lock, flags);
idetape_plug_pipeline(drive);
if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE,
&tape->flags))
continue;
return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
blocks, tape->merge_stage->bh);
}
}
}

/*
* Wait until all pending pipeline requests are serviced. Typically called on
* device close.
*/
static void idetape_wait_for_pipeline(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
unsigned long flags;

while (tape->next_stage || test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE,
&tape->flags)) {
idetape_plug_pipeline(drive);
spin_lock_irqsave(&tape->lock, flags);
if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags))
idetape_wait_for_request(drive, tape->active_data_rq);
spin_unlock_irqrestore(&tape->lock, flags);
}
return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
blocks, tape->merge_stage->bh);
}

static void idetape_empty_write_pipeline(ide_drive_t *drive)
Expand Down Expand Up @@ -2020,7 +1927,6 @@ static void idetape_empty_write_pipeline(ide_drive_t *drive)
(void) idetape_add_chrdev_write_request(drive, blocks);
tape->merge_stage_size = 0;
}
idetape_wait_for_pipeline(drive);
if (tape->merge_stage != NULL) {
__idetape_kfree_stage(tape->merge_stage);
tape->merge_stage = NULL;
Expand Down Expand Up @@ -2093,7 +1999,6 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
tape->insert_time = jiffies;
tape->insert_size = 0;
tape->insert_speed = 0;
idetape_plug_pipeline(drive);
}
}
return 0;
Expand Down Expand Up @@ -2593,7 +2498,6 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
idetape_flush_tape_buffers(drive);
}
if (cmd == MTIOCGET || cmd == MTIOCPOS) {
idetape_wait_for_pipeline(drive);
block_offset = tape->merge_stage_size /
(tape->blk_size * tape->user_bs_factor);
position = idetape_read_position(drive);
Expand Down Expand Up @@ -2772,8 +2676,6 @@ static int idetape_chrdev_release(struct inode *inode, struct file *filp)
if (tape->chrdev_dir == IDETAPE_DIR_READ) {
if (minor < 128)
idetape_discard_read_pipeline(drive, 1);
else
idetape_wait_for_pipeline(drive);
}

if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
Expand Down

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