tree 540c780f1bb691971d55bffdbecec972ffa5e5eb
parent dc501dc0d9dc9cbabc18b920f91a26c207e9476c
author Robert Elliott <elliott@hp.com> 1409675924 -0500
committer Jens Axboe <axboe@fb.com> 1409762655 -0600

blk-mq: cleanup after blk_mq_init_rq_map failures

In blk-mq.c blk_mq_alloc_tag_set, if:
	set->tags = kmalloc_node()
succeeds, but one of the blk_mq_init_rq_map() calls fails,
	goto out_unwind;
needs to free set->tags so the caller is not obligated
to do so.  None of the current callers (null_blk,
virtio_blk, virtio_blk, or the forthcoming scsi-mq)
do so.

set->tags needs to be set to NULL after doing so,
so other tag cleanup logic doesn't try to free
a stale pointer later.  Also set it to NULL
in blk_mq_free_tag_set.

Tested with error injection on the forthcoming
scsi-mq + hpsa combination.

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>