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[SCSI] remove a timer race in scsi_queue_insert() 

scsi_queue_insert() has four callers.  Three callers call with
timer disabled and one (the second invocation in
scsi_dispatch_cmd()) calls with timer activated.
scsi_queue_insert() used to always call scsi_delete_timer()
and ignore the return value.  This results in race with timer
expiration.  Remove scsi_delete_timer() call from
scsi_queue_insert() and make the caller delete timer and check
the return value.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This commit is contained in:
Tejun Heo 2005-05-14 00:46:08 +09:00 committed by James Bottomley
parent 5b8ef84258
commit d8c37e7b9a
2 changed files with 7 additions and 11 deletions
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10
drivers/scsi/scsi.c
View File

@ -638,10 +638,12 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
}
spin_unlock_irqrestore(host->host_lock, flags);
if (rtn) {
atomic_inc(&cmd->device->iodone_cnt);
scsi_queue_insert(cmd,
(rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
rtn : SCSI_MLQUEUE_HOST_BUSY);
if (scsi_delete_timer(cmd)) {
atomic_inc(&cmd->device->iodone_cnt);
scsi_queue_insert(cmd,
(rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
rtn : SCSI_MLQUEUE_HOST_BUSY);
}
SCSI_LOG_MLQUEUE(3,
printk("queuecommand : request rejected\n"));
}

8
drivers/scsi/scsi_lib.c
View File

@ -128,13 +128,7 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
printk("Inserting command %p into mlqueue\n", cmd));
/*
* We are inserting the command into the ml queue. First, we
* cancel the timer, so it doesn't time out.
*/
scsi_delete_timer(cmd);
/*
* Next, set the appropriate busy bit for the device/host.
* Set the appropriate busy bit for the device/host.
*
* If the host/device isn't busy, assume that something actually
* completed, and that we should be able to queue a command now.