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authorTejun Heo <tj@kernel.org>2009-05-08 06:53:59 +0400
committerJens Axboe <jens.axboe@oracle.com>2009-05-11 11:52:14 +0400
commit8f6205cd572fece673da0255d74843680f67f879 (patch)
treebb89c1c5fe4436f5a0ec27f0d96074c7031a83ae /drivers/ide/ide-io.c
parent1011c1b9f2e45ce7c6e38888d2b83936aec38771 (diff)
downloadlinux-8f6205cd572fece673da0255d74843680f67f879.tar.xz
ide: dequeue in-flight request
ide generally has single request in flight and tracks it using hwif->rq and all state handlers follow the following convention. * ide_started is returned if the request is in flight. * ide_stopped is returned if the queue needs to be restarted. The request might or might not have been processed fully or partially. * hwif->rq is set to NULL, when an issued request completes. So, dequeueing model can be implemented by dequeueing after fetch, requeueing if hwif->rq isn't NULL on ide_stopped return and doing about the same thing on completion / port unlock paths. These changes can be made in ide-io proper. In addition to the above main changes, the following updates are necessary. * ide-cd shouldn't dequeue a request when issuing REQUEST SENSE for it as the request is already dequeued. * ide-atapi uses request queue as stack when issuing REQUEST SENSE to put the REQUEST SENSE in front of the failed request. This now needs to be done using requeueing. [ Impact: dequeue in-flight request ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'drivers/ide/ide-io.c')
-rw-r--r--drivers/ide/ide-io.c34
1 files changed, 27 insertions, 7 deletions
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index ca2519d7b994..abda7337b3f4 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -487,10 +487,10 @@ void do_ide_request(struct request_queue *q)
if (!ide_lock_port(hwif)) {
ide_hwif_t *prev_port;
+
+ WARN_ON_ONCE(hwif->rq);
repeat:
prev_port = hwif->host->cur_port;
- hwif->rq = NULL;
-
if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
time_after(drive->sleep, jiffies)) {
ide_unlock_port(hwif);
@@ -519,7 +519,12 @@ repeat:
* we know that the queue isn't empty, but this can happen
* if the q->prep_rq_fn() decides to kill a request
*/
- rq = elv_next_request(drive->queue);
+ if (!rq) {
+ rq = elv_next_request(drive->queue);
+ if (rq)
+ blkdev_dequeue_request(rq);
+ }
+
spin_unlock_irq(q->queue_lock);
spin_lock_irq(&hwif->lock);
@@ -555,8 +560,11 @@ repeat:
startstop = start_request(drive, rq);
spin_lock_irq(&hwif->lock);
- if (startstop == ide_stopped)
+ if (startstop == ide_stopped) {
+ rq = hwif->rq;
+ hwif->rq = NULL;
goto repeat;
+ }
} else
goto plug_device;
out:
@@ -572,18 +580,24 @@ plug_device:
plug_device_2:
spin_lock_irq(q->queue_lock);
+ if (rq)
+ blk_requeue_request(q, rq);
if (!elv_queue_empty(q))
blk_plug_device(q);
}
-static void ide_plug_device(ide_drive_t *drive)
+static void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
{
struct request_queue *q = drive->queue;
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
+
+ if (rq)
+ blk_requeue_request(q, rq);
if (!elv_queue_empty(q))
blk_plug_device(q);
+
spin_unlock_irqrestore(q->queue_lock, flags);
}
@@ -632,6 +646,7 @@ void ide_timer_expiry (unsigned long data)
unsigned long flags;
int wait = -1;
int plug_device = 0;
+ struct request *uninitialized_var(rq_in_flight);
spin_lock_irqsave(&hwif->lock, flags);
@@ -693,6 +708,8 @@ void ide_timer_expiry (unsigned long data)
spin_lock_irq(&hwif->lock);
enable_irq(hwif->irq);
if (startstop == ide_stopped) {
+ rq_in_flight = hwif->rq;
+ hwif->rq = NULL;
ide_unlock_port(hwif);
plug_device = 1;
}
@@ -701,7 +718,7 @@ void ide_timer_expiry (unsigned long data)
if (plug_device) {
ide_unlock_host(hwif->host);
- ide_plug_device(drive);
+ ide_requeue_and_plug(drive, rq_in_flight);
}
}
@@ -787,6 +804,7 @@ irqreturn_t ide_intr (int irq, void *dev_id)
ide_startstop_t startstop;
irqreturn_t irq_ret = IRQ_NONE;
int plug_device = 0;
+ struct request *uninitialized_var(rq_in_flight);
if (host->host_flags & IDE_HFLAG_SERIALIZE) {
if (hwif != host->cur_port)
@@ -866,6 +884,8 @@ irqreturn_t ide_intr (int irq, void *dev_id)
*/
if (startstop == ide_stopped) {
BUG_ON(hwif->handler);
+ rq_in_flight = hwif->rq;
+ hwif->rq = NULL;
ide_unlock_port(hwif);
plug_device = 1;
}
@@ -875,7 +895,7 @@ out:
out_early:
if (plug_device) {
ide_unlock_host(hwif->host);
- ide_plug_device(drive);
+ ide_requeue_and_plug(drive, rq_in_flight);
}
return irq_ret;