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PATCH: st.c: Fix blk_get_queue usage

PATCH Bodo Stroesser 2 participants 2 messages Nov 14, 2013

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SCSI SCSI tape driver
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Bodo Stroesser

author
#0 lore raw

Hi,

in st_probe(), st.c I stumbled across what I'd call a minor problem.

So I'd like to suggest the following patch.

Best Regards,
Bodo

P.S.: Please CC me, I'm not on the list.

---------------------------------------------------------------------

From: Bodo Stroesser <[email protected]>
Date: Thu, 14 Nov 2013 14:35:00 +0100
Subject: [PATCH] sg: fix blk_get_queue usage

If blk_queue_get() in st_probe fails, disk->queue must not be set to SDp->request_queue, as that would result in put_disk() dropping a not taken reference.

Thus, disk->queue should be set only after a successful blk_queue_get().

Signed-off-by Bodo Stroesser <[email protected]>

---

drivers/scsi/st.c +1 -1
@@ -4107,11 +4107,11 @@
 	kref_init(&tpnt->kref);
 	tpnt->disk = disk;
 	disk->private_data = &tpnt->driver;
-	disk->queue = SDp->request_queue;
 	/* SCSI tape doesn't register this gendisk via add_disk().  Manually
 	 * take queue reference that release_disk() expects. */
 	if (blk_get_queue(disk->queue))
 		goto out_put_disk;
+	disk->queue = SDp->request_queue;
 	tpnt->driver = &st_template;
 
 	tpnt->device = SDp;
#1 lore raw
Quoted 32 lines · Bodo Stroesser

Hi,

in st_probe(), st.c I stumbled across what I'd call a minor problem.

So I'd like to suggest the following patch.

Best Regards,
Bodo

P.S.: Please CC me, I'm not on the list.

---------------------------------------------------------------------

From: Bodo Stroesser <[email protected]>
Date: Thu, 14 Nov 2013 14:35:00 +0100
Subject: [PATCH] sg: fix blk_get_queue usage

If blk_queue_get() in st_probe fails, disk->queue must not be set to SDp->request_queue, as that would result in put_disk() dropping a not taken reference.

Thus, disk->queue should be set only after a successful blk_queue_get().

Signed-off-by Bodo Stroesser <[email protected]>

---

drivers/scsi/st.c line 4111

Quoted 6 lines
drivers/scsi/st.c +0 -1
@@ -4107,11 +4107,11 @@
 	kref_init(&tpnt->kref);
 	tpnt->disk = disk;
 	disk->private_data = &tpnt->driver;
-	disk->queue = SDp->request_queue;
 	/* SCSI tape doesn't register this gendisk via add_disk().  Manually
 	 * take queue reference that release_disk() expects. */

With this patch, blk_get_queue() is not called with the correct argument. Maybe change the call to blk_get_queue(SDp->request_queue) ?

Quoted 10 lines
drivers/scsi/st.c +1 -0
 	if (blk_get_queue(disk->queue))
 		goto out_put_disk;
+	disk->queue = SDp->request_queue;
 	tpnt->driver = &st_template;
 
 	tpnt->device = SDp--

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Thanks,
Kai