diff options
| author | Mike Christie <michaelc@cs.wisc.edu> | 2008-11-11 13:42:35 -0600 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2008-11-16 08:13:58 -0600 |
| commit | 2a3a59e5c977654d3aad5bc11cc0aca2303a7f44 (patch) | |
| tree | 4449aa49696e54a3a62fc595449be8caa89188f1 /drivers/scsi/scsi_lib.c | |
| parent | 9bf1a2445f3c569098b8de7097ca324e65abecc2 (diff) | |
[SCSI] Fix hang in starved list processing
Close possible infinite loop with interrupts off when devices are
added back to the starved list.
Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=11898
Reported-by: <alex.shi@intel.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index f5d3b96890dc..fa45a1a66867 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -567,15 +567,18 @@ static inline int scsi_host_is_busy(struct Scsi_Host *shost) */ static void scsi_run_queue(struct request_queue *q) { - struct scsi_device *starved_head = NULL, *sdev = q->queuedata; + struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost = sdev->host; + LIST_HEAD(starved_list); unsigned long flags; if (scsi_target(sdev)->single_lun) scsi_single_lun_run(sdev); spin_lock_irqsave(shost->host_lock, flags); - while (!list_empty(&shost->starved_list) && !scsi_host_is_busy(shost)) { + list_splice_init(&shost->starved_list, &starved_list); + + while (!list_empty(&starved_list)) { int flagset; /* @@ -588,24 +591,18 @@ static void scsi_run_queue(struct request_queue *q) * scsi_request_fn must get the host_lock before checking * or modifying starved_list or starved_entry. */ - sdev = list_entry(shost->starved_list.next, - struct scsi_device, starved_entry); - /* - * The *queue_ready functions can add a device back onto the - * starved list's tail, so we must check for a infinite loop. - */ - if (sdev == starved_head) + if (scsi_host_is_busy(shost)) break; - if (!starved_head) - starved_head = sdev; + sdev = list_entry(starved_list.next, + struct scsi_device, starved_entry); + list_del_init(&sdev->starved_entry); if (scsi_target_is_busy(scsi_target(sdev))) { list_move_tail(&sdev->starved_entry, &shost->starved_list); continue; } - list_del_init(&sdev->starved_entry); spin_unlock(shost->host_lock); spin_lock(sdev->request_queue->queue_lock); @@ -621,6 +618,8 @@ static void scsi_run_queue(struct request_queue *q) spin_lock(shost->host_lock); } + /* put any unprocessed entries back */ + list_splice(&starved_list, &shost->starved_list); spin_unlock_irqrestore(shost->host_lock, flags); blk_run_queue(q); |