From 8f6205cd572fece673da0255d74843680f67f879 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 8 May 2009 11:53:59 +0900 Subject: 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 Cc: Bartlomiej Zolnierkiewicz Cc: Borislav Petkov Cc: Sergei Shtylyov Signed-off-by: Jens Axboe --- drivers/ide/ide-io.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) (limited to 'drivers/ide/ide-io.c') diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c index ca2519d7b99..abda7337b3f 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; -- cgit v1.2.3-18-g5258