[patch 20/45] block: dont assume device has a request list backing in nr_requests store

[Greg KH]

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Jens Axboe <jens.axboe@xxxxxxxxxx>

commit b8a9ae779f2c7049071034661e09cb7e1e82250c upstream.

Stacked devices do not. For now, just error out with -EINVAL. Later
we could make the limit apply on stacked devices too, for throttling
reasons.

This fixes

5a54cd13353bb3b88887604e2c980aa01e314309

and should go into 2.6.31 stable as well.

Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 block/blk-sysfs.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -40,7 +40,12 @@ queue_requests_store(struct request_queu
 {
 	struct request_list *rl = &q->rq;
 	unsigned long nr;
-	int ret = queue_var_store(&nr, page, count);
+	int ret;
+
+	if (!q->request_fn)
+		return -EINVAL;
+
+	ret = queue_var_store(&nr, page, count);
 	if (nr < BLKDEV_MIN_RQ)
 		nr = BLKDEV_MIN_RQ;
 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/