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author <axboe@suse.de>2005-04-12 16:22:06 -0500
committerJames Bottomley <jejb@titanic>2005-04-16 20:10:09 -0500
commit152587deb8903c0edf483a5b889f975bc6bea7e0 (patch)
tree62fc13bff0a28134adbb523ed1a2c0efdd9a85cb
parent56fece20086ebe32bce2c0d74ceadd516b56baae (diff)
[PATCH] fix NMI lockup with CFQ scheduler
The current problem seen is that the queue lock is actually in the SCSI device structure, so when that structure is freed on device release, we go boom if the queue tries to access the lock again. The fix here is to move the lock from the scsi_device to the queue. Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
-rw-r--r--drivers/block/ll_rw_blk.c9
-rw-r--r--drivers/scsi/scsi_lib.c6
-rw-r--r--drivers/scsi/scsi_scan.c1
-rw-r--r--include/linux/blkdev.h5
-rw-r--r--include/scsi/scsi_device.h1
5 files changed, 16 insertions, 6 deletions
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index 46e54b44166..11ef9d9ea13 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -1715,6 +1715,15 @@ request_queue_t *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
if (blk_init_free_list(q))
goto out_init;
+ /*
+ * if caller didn't supply a lock, they get per-queue locking with
+ * our embedded lock
+ */
+ if (!lock) {
+ spin_lock_init(&q->__queue_lock);
+ lock = &q->__queue_lock;
+ }
+
q->request_fn = rfn;
q->back_merge_fn = ll_back_merge_fn;
q->front_merge_fn = ll_front_merge_fn;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 7cbc4127fb5..d230c699c72 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -360,9 +360,9 @@ void scsi_device_unbusy(struct scsi_device *sdev)
shost->host_failed))
scsi_eh_wakeup(shost);
spin_unlock(shost->host_lock);
- spin_lock(&sdev->sdev_lock);
+ spin_lock(sdev->request_queue->queue_lock);
sdev->device_busy--;
- spin_unlock_irqrestore(&sdev->sdev_lock, flags);
+ spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
}
/*
@@ -1425,7 +1425,7 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
struct Scsi_Host *shost = sdev->host;
struct request_queue *q;
- q = blk_init_queue(scsi_request_fn, &sdev->sdev_lock);
+ q = blk_init_queue(scsi_request_fn, NULL);
if (!q)
return NULL;
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index a8a37a338c0..287d197a7c1 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -249,7 +249,6 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
*/
sdev->borken = 1;
- spin_lock_init(&sdev->sdev_lock);
sdev->request_queue = scsi_alloc_queue(sdev);
if (!sdev->request_queue) {
/* release fn is set up in scsi_sysfs_device_initialise, so
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 70ac2860a60..ef1afc178c0 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -355,8 +355,11 @@ struct request_queue
unsigned long queue_flags;
/*
- * protects queue structures from reentrancy
+ * protects queue structures from reentrancy. ->__queue_lock should
+ * _never_ be used directly, it is queue private. always use
+ * ->queue_lock.
*/
+ spinlock_t __queue_lock;
spinlock_t *queue_lock;
/*
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 07d974051b0..f6d05131829 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -44,7 +44,6 @@ struct scsi_device {
struct list_head same_target_siblings; /* just the devices sharing same target id */
volatile unsigned short device_busy; /* commands actually active on low-level */
- spinlock_t sdev_lock; /* also the request queue_lock */
spinlock_t list_lock;
struct list_head cmd_list; /* queue of in use SCSI Command structures */
struct list_head starved_entry;