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Date: Sat, 1 Mar 2008 09:58:26 +0100
From: Borislav Petkov <petkovbb@...glemail.com>
To: <bzolnier@...il.com>
Cc: linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org,
Borislav Petkov <petkovbb@...il.com>
Subject: [PATCH 02/24] ide-tape: remove pipeline-specific code from idetape_add_chrdev_write_request
Instead of plugging the request into the pipeline, queue it straight on the
device's request queue through idetape_queue_rw_tail().
Signed-off-by: Borislav Petkov <petkovbb@...il.com>
---
drivers/ide/ide-tape.c | 81 ++---------------------------------------------
1 files changed, 4 insertions(+), 77 deletions(-)
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 792c76e..abf3efa 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -2123,12 +2123,6 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
- if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
- printk(KERN_ERR "ide-tape: bug: the pipeline is active in %s\n",
- __func__);
- return (0);
- }
-
idetape_init_rq(&rq, cmd);
rq.rq_disk = tape->disk;
rq.special = (void *)bh;
@@ -2140,10 +2134,9 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
return 0;
- if (tape->merge_stage)
- idetape_init_merge_stage(tape);
if (rq.errors == IDETAPE_ERROR_GENERAL)
return -EIO;
+
return (tape->blk_size * (blocks-rq.current_nr_sectors));
}
@@ -2210,81 +2203,15 @@ static void idetape_wait_first_stage(ide_drive_t *drive)
spin_unlock_irqrestore(&tape->lock, flags);
}
-/*
- * Try to add a character device originated write request to our pipeline. In
- * case we don't succeed, we revert to non-pipelined operation mode for this
- * request. In order to accomplish that, we
- *
- * 1. Try to allocate a new pipeline stage.
- * 2. If we can't, wait for more and more requests to be serviced and try again
- * each time.
- * 3. If we still can't allocate a stage, fallback to non-pipelined operation
- * mode for this request.
- */
+/* 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;
- idetape_stage_t *new_stage;
- unsigned long flags;
- struct request *rq;
debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
- /* Attempt to allocate a new stage. Beware possible race conditions. */
- while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
- 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;
- /*
- * The machine is short on memory. Fallback to non-
- * pipelined operation mode for this request.
- */
- return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
- blocks, tape->merge_stage->bh);
- }
- }
- rq = &new_stage->rq;
- idetape_init_rq(rq, REQ_IDETAPE_WRITE);
- /* Doesn't actually matter - We always assume sequential access */
- rq->sector = tape->first_frame;
- rq->current_nr_sectors = blocks;
- rq->nr_sectors = blocks;
-
- idetape_switch_buffers(tape, new_stage);
- idetape_add_stage_tail(drive, new_stage);
- tape->pipeline_head++;
- idetape_calculate_speeds(drive);
-
- /*
- * Estimate whether the tape has stopped writing by checking if our
- * write pipeline is currently empty. If we are not writing anymore,
- * wait for the pipeline to be almost completely full (90%) before
- * starting to service requests, so that we will be able to keep up with
- * the higher speeds of the tape.
- */
- if (!test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
- if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
- tape->nr_stages >= tape->max_stages -
- tape->uncontrolled_pipeline_head_speed * 3 * 1024 /
- tape->blk_size) {
- tape->measure_insert_time = 1;
- tape->insert_time = jiffies;
- tape->insert_size = 0;
- tape->insert_speed = 0;
- idetape_plug_pipeline(drive);
- }
- }
- if (test_and_clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
- /* Return a deferred error */
- return -EIO;
- return blocks;
+ return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
+ tape->merge_stage->bh);
}
/*
--
1.5.4.1
--
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