From 3e6180f0c82b3790a9ec6d13d67aae359bf1ce84 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 30 Apr 2015 10:10:36 -0400 Subject: [PATCH] dm: only initialize the request_queue once Commit bfebd1cdb4 ("dm: add full blk-mq support to request-based DM") didn't properly account for the need to short-circuit re-initializing DM's blk-mq request_queue if it was already initialized. Otherwise, reloading a blk-mq request-based DM table (either manually or via multipathd) resulted in errors, see: https://www.redhat.com/archives/dm-devel/2015-April/msg00132.html Fix is to only initialize the request_queue on the initial table load (when the mapped_device type is assigned). This is better than having dm_init_request_based_blk_mq_queue() return early if the queue was already initialized because it elevates the constraint to a more meaningful location in DM core. As such the pre-existing early return in dm_init_request_based_queue() can now be removed. Fixes: bfebd1cdb4 ("dm: add full blk-mq support to request-based DM") Signed-off-by: Christoph Hellwig Signed-off-by: Mike Snitzer --- drivers/md/dm-ioctl.c | 17 +++++++++-------- drivers/md/dm.c | 3 --- 2 files changed, 9 insertions(+), 11 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index c8a18e4..720ceeb 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1298,21 +1298,22 @@ static int table_load(struct dm_ioctl *param, size_t param_size) goto err_unlock_md_type; } - if (dm_get_md_type(md) == DM_TYPE_NONE) + if (dm_get_md_type(md) == DM_TYPE_NONE) { /* Initial table load: acquire type of table. */ dm_set_md_type(md, dm_table_get_type(t)); - else if (dm_get_md_type(md) != dm_table_get_type(t)) { + + /* setup md->queue to reflect md's type (may block) */ + r = dm_setup_md_queue(md); + if (r) { + DMWARN("unable to set up device queue for new table."); + goto err_unlock_md_type; + } + } else if (dm_get_md_type(md) != dm_table_get_type(t)) { DMWARN("can't change device type after initial table load."); r = -EINVAL; goto err_unlock_md_type; } - /* setup md->queue to reflect md's type (may block) */ - r = dm_setup_md_queue(md); - if (r) { - DMWARN("unable to set up device queue for new table."); - goto err_unlock_md_type; - } dm_unlock_md_type(md); /* stage inactive table */ diff --git a/drivers/md/dm.c b/drivers/md/dm.c index f8c7ca3..923496ba 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2662,9 +2662,6 @@ static int dm_init_request_based_queue(struct mapped_device *md) { struct request_queue *q = NULL; - if (md->queue->elevator) - return 0; - /* Fully initialize the queue */ q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL); if (!q) -- 2.7.4