projects / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 2cb7cef9 BS |
1 | Subject: [SCSI] Fix hang in starved list processing |
| 2 | From: Mike Christie <michaelc@cs.wisc.edu> | |
| 3 | Date: Sun Nov 16 08:13:58 2008 -0600: | |
| 4 | Git: 2a3a59e5c977654d3aad5bc11cc0aca2303a7f44 | |
| 5 | References: bnc#464155 | |
| 6 | ||
| 7 | Close possible infinite loop with interrupts off when devices are | |
| 8 | added back to the starved list. | |
| 9 | ||
| 10 | Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=11898 | |
| 11 | ||
| 12 | Reported-by: <alex.shi@intel.com> | |
| 13 | Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> | |
| 14 | Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> | |
| 15 | Signed-off-by: Hannes Reinecke <hare@suse.de> | |
| 16 | ||
| 17 | diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c | |
| 18 | index f5d3b96..fa45a1a 100644 | |
| 19 | --- a/drivers/scsi/scsi_lib.c | |
| 20 | +++ b/drivers/scsi/scsi_lib.c | |
| 21 | @@ -567,15 +567,18 @@ static inline int scsi_host_is_busy(struct Scsi_Host *shost) | |
| 22 | */ | |
| 23 | static void scsi_run_queue(struct request_queue *q) | |
| 24 | { | |
| 25 | - struct scsi_device *starved_head = NULL, *sdev = q->queuedata; | |
| 26 | + struct scsi_device *sdev = q->queuedata; | |
| 27 | struct Scsi_Host *shost = sdev->host; | |
| 28 | + LIST_HEAD(starved_list); | |
| 29 | unsigned long flags; | |
| 30 | ||
| 31 | if (scsi_target(sdev)->single_lun) | |
| 32 | scsi_single_lun_run(sdev); | |
| 33 | ||
| 34 | spin_lock_irqsave(shost->host_lock, flags); | |
| 35 | - while (!list_empty(&shost->starved_list) && !scsi_host_is_busy(shost)) { | |
| 36 | + list_splice_init(&shost->starved_list, &starved_list); | |
| 37 | + | |
| 38 | + while (!list_empty(&starved_list)) { | |
| 39 | int flagset; | |
| 40 | ||
| 41 | /* | |
| 42 | @@ -588,24 +591,18 @@ static void scsi_run_queue(struct request_queue *q) | |
| 43 | * scsi_request_fn must get the host_lock before checking | |
| 44 | * or modifying starved_list or starved_entry. | |
| 45 | */ | |
| 46 | - sdev = list_entry(shost->starved_list.next, | |
| 47 | - struct scsi_device, starved_entry); | |
| 48 | - /* | |
| 49 | - * The *queue_ready functions can add a device back onto the | |
| 50 | - * starved list's tail, so we must check for a infinite loop. | |
| 51 | - */ | |
| 52 | - if (sdev == starved_head) | |
| 53 | + if (scsi_host_is_busy(shost)) | |
| 54 | break; | |
| 55 | - if (!starved_head) | |
| 56 | - starved_head = sdev; | |
| 57 | ||
| 58 | + sdev = list_entry(starved_list.next, | |
| 59 | + struct scsi_device, starved_entry); | |
| 60 | + list_del_init(&sdev->starved_entry); | |
| 61 | if (scsi_target_is_busy(scsi_target(sdev))) { | |
| 62 | list_move_tail(&sdev->starved_entry, | |
| 63 | &shost->starved_list); | |
| 64 | continue; | |
| 65 | } | |
| 66 | ||
| 67 | - list_del_init(&sdev->starved_entry); | |
| 68 | spin_unlock(shost->host_lock); | |
| 69 | ||
| 70 | spin_lock(sdev->request_queue->queue_lock); | |
| 71 | @@ -621,6 +618,8 @@ static void scsi_run_queue(struct request_queue *q) | |
| 72 | ||
| 73 | spin_lock(shost->host_lock); | |
| 74 | } | |
| 75 | + /* put any unprocessed entries back */ | |
| 76 | + list_splice(&starved_list, &shost->starved_list); | |
| 77 | spin_unlock_irqrestore(shost->host_lock, flags); | |
| 78 | ||
| 79 | blk_run_queue(q); |