Hi all,
the following patch applies to 2.6.26-rc8. However, the same issues
exist in the 2.6.25.y stable tree and the patch applies with offsets to
2.6.25.9; I haven't checked 2.6.24 and before.
Regards,
Elias
From: Elias Oltmanns <eo@xxxxxxxxxxxxxx>
Subject: SCSI: Fix some locking issues
Make sure that host_blocked is consistently protected by the host_lock.
Similarly, device_block has to be protected by the queue_lock. Also,
blk_plug_device() has to be called with the queue_lock held in
scsi_host_queue_ready().
Cc: stable@xxxxxxxxxx
Signed-off-by: Elias Oltmanns <eo@xxxxxxxxxxxxxx>
---
drivers/scsi/scsi.c | 6 ++++++
drivers/scsi/scsi_lib.c | 13 +++++++++++--
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 110e776..b8b7982 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -826,8 +826,10 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
{
struct scsi_device *sdev = cmd->device;
struct Scsi_Host *shost = sdev->host;
+ struct request_queue *q = sdev->request_queue;
struct scsi_driver *drv;
unsigned int good_bytes;
+ unsigned long flags;
scsi_device_unbusy(sdev);
@@ -839,8 +841,12 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
*
* XXX(hch): What about locking?
*/
+ spin_lock_irqsave(shost->host_lock, flags);
shost->host_blocked = 0;
+ spin_unlock(shost->host_lock);
+ spin_lock(q->queue_lock);
sdev->device_blocked = 0;
+ spin_unlock_irqrestore(q->queue_lock, flags);
/*
* If we have valid sense information, then some kind of recovery
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a82d2fe..65d0c39 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -133,10 +133,15 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
* if a command is requeued with no other commands outstanding
* either for the device or for the host.
*/
- if (reason == SCSI_MLQUEUE_HOST_BUSY)
+ if (reason == SCSI_MLQUEUE_HOST_BUSY) {
+ spin_lock_irqsave(host->host_lock, flags);
host->host_blocked = host->max_host_blocked;
- else if (reason == SCSI_MLQUEUE_DEVICE_BUSY)
+ spin_unlock_irqrestore(host->host_lock, flags);
+ } else if (reason == SCSI_MLQUEUE_DEVICE_BUSY) {
+ spin_lock_irqsave(q->queue_lock, flags);
device->device_blocked = device->max_device_blocked;
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
/*
* Decrement the counters, since these commands are no longer
@@ -1320,7 +1325,11 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
printk("scsi%d unblocking host at zero depth\n",
shost->host_no));
} else {
+ spin_unlock(shost->host_lock);
+ spin_lock(q->queue_lock);
blk_plug_device(q);
+ spin_unlock(q->queue_lock);
+ spin_lock(shost->host_lock);
return 0;
}
}
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