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authorAlasdair G Kergon <agk@redhat.com>2008-10-10 13:37:13 +0100
committerAlasdair G Kergon <agk@redhat.com>2008-10-10 13:37:13 +0100
commit0c2322e4ce144e130c03d813fe92de3798662c5e (patch)
treea42eeb1a75d9e70a20a6d4d850064ba8292c2289
parent54160904260fa764ba6e2dc738770be30fdf9553 (diff)
dm: detect lost queue
Detect and report buggy drivers that destroy their request_queue. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Stefan Raspl <raspl@linux.vnet.ibm.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--drivers/md/dm-table.c26
1 files changed, 23 insertions, 3 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 5dd32b8a57a..a740a6950f5 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -482,6 +482,13 @@ void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
{
struct request_queue *q = bdev_get_queue(bdev);
struct io_restrictions *rs = &ti->limits;
+ char b[BDEVNAME_SIZE];
+
+ if (unlikely(!q)) {
+ DMWARN("%s: Cannot set limits for nonexistent device %s",
+ dm_device_name(ti->table->md), bdevname(bdev, b));
+ return;
+ }
/*
* Combine the device limits low.
@@ -950,7 +957,14 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits)
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
- r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+ char b[BDEVNAME_SIZE];
+
+ if (likely(q))
+ r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+ else
+ DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
+ dm_device_name(t->md),
+ bdevname(dd->dm_dev.bdev, b));
}
return r;
@@ -963,8 +977,14 @@ void dm_table_unplug_all(struct dm_table *t)
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
-
- blk_unplug(q);
+ char b[BDEVNAME_SIZE];
+
+ if (likely(q))
+ blk_unplug(q);
+ else
+ DMWARN_LIMIT("%s: Cannot unplug nonexistent device %s",
+ dm_device_name(t->md),
+ bdevname(dd->dm_dev.bdev, b));
}
}