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authorTejun Heo <tj@kernel.org>2010-04-08 01:45:46 -0700
committerDavid S. Miller <davem@davemloft.net>2010-10-26 10:17:30 -0700
commitdd8717da6da9b0e745df49762be4573010f1013c (patch)
treee1875e541ce097b30edc17e431b4dd7074218c00
parentbbe54d78cc59a39f1ef3ffbe70423376ad9aab4c (diff)
ide: clean up timed out request handling
8f6205cd572fece673da0255d74843680f67f879 introduced a bug where a timed out DMA request is never requeued and lost. 6072f7491f5ef391a575e18a1165e72a3eef1601 fixed this by making ide_dma_timeout_retry() requeue the request itself. While the fix is correct, it makes DMA and non-DMA paths asymmetric regarding how the in flight request is requeued. As long as hwif->rq is set, the IDE driver is assuming ownership of the request and the request should either be completed or requeued when clearing hwif->rq. In the timeout path, the ide driver holds onto the request as long as the recovery action (ie. reset) is in progress and clears it after the state machine is stopped (ide_stopped return), so the existing requeueing logic is correct. The bug occurred because ide_dma_timeout_retry() explicitly clears hwif->rq without requeueing it. ide_dma_timeout_retry() is called only by ide_timer_expiry() and returns ide_started only when ide_error() would return it - ie. after reset state machine has started in which case the state machine will eventually end up executing the ide_stopped path in ide_timer_expiry() after reset protocol is complete. So, there is no need to clear hwif->rq from ide_dma_timeout_retry(). ide_timer_expiry() will handle it the same way as PIO timeout path. Kill hwif->rq clearing and requeueing from ide_dma_timeout_retry() and let ide_timer_expiry() deal with it. The end result should remain the same. grepping shows ide_dma_timeout_retry() is the only site which clears hwif->rq without taking care of the request, so there shouldn't be similar fallouts. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/ide/ide-dma.c11
1 files changed, 3 insertions, 8 deletions
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index 06b14bc9a1d..d4136908f91 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -449,7 +449,6 @@ ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
ide_hwif_t *hwif = drive->hwif;
const struct ide_dma_ops *dma_ops = hwif->dma_ops;
struct ide_cmd *cmd = &hwif->cmd;
- struct request *rq;
ide_startstop_t ret = ide_stopped;
/*
@@ -487,14 +486,10 @@ ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
ide_dma_off_quietly(drive);
/*
- * un-busy drive etc and make sure request is sane
+ * make sure request is sane
*/
- rq = hwif->rq;
- if (rq) {
- hwif->rq = NULL;
- rq->errors = 0;
- ide_requeue_and_plug(drive, rq);
- }
+ if (hwif->rq)
+ hwif->rq->errors = 0;
return ret;
}