[SCSI] fix up scsi_eh_lock_door()

The Documentation is incorrect (we removed some functions referred to), and
none of the bug warnings now apply.  Additionally remove the spurious check on
the return from blk_get_request() which can't fail if __GFP_WAIT is passed in.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index a95d2ba..a168935 100644 (file)
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1451,28 +1451,21 @@ static void eh_lock_door_done(struct request *req, int uptodate)
  * @sdev:      SCSI device to prevent medium removal
  *
  * Locking:
- *     We must be called from process context; scsi_allocate_request()
- *     may sleep.
+ *     We must be called from process context.
  *
  * Notes:
  *     We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
  *     head of the devices request queue, and continue.
- *
- * Bugs:
- *     scsi_allocate_request() may sleep waiting for existing requests to
- *     be processed.  However, since we haven't kicked off any request
- *     processing for this host, this may deadlock.
- *
- *     If scsi_allocate_request() fails for what ever reason, we
- *     completely forget to lock the door.
  */
 static void scsi_eh_lock_door(struct scsi_device *sdev)
 {
        struct request *req;
 
+       /*
+        * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
+        * request becomes available
+        */
        req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
-       if (!req)
-               return;
 
        req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
        req->cmd[1] = 0;