block: check for dying queue in generic_make_request()

From: Asai Thambi S P
Date: Wed Apr 16 2014 - 23:32:11 EST



Check for dying queue is in request queue interface, but not for direct use
of make_request().

When a mounted device is surprise removed, block drivers delete gendisk and
cleanup request queue. As the reference count is non-zero, these structures
continue to exist and any further I/O request is passed on to block drivers.
With respect to the block driver, the device is removed and cleaned up the
data structures. This check will stop I/O to a non-existent device at the
block layer.

Signed-off-by: Asai Thambi S P <asamymuthupa@xxxxxxxxxx>
---
block/blk-core.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index e45b321..cec6bf4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1713,7 +1713,7 @@ generic_make_request_checks(struct bio *bio)
goto end_io;

q = bdev_get_queue(bio->bi_bdev);
- if (unlikely(!q)) {
+ if (unlikely(!q || blk_queue_dying(q))) {
printk(KERN_ERR
"generic_make_request: Trying to access "
"nonexistent block-device %s (%Lu)\n",
--
1.7.1

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