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authorMike Snitzer <snitzer@redhat.com>2014-12-17 21:08:12 -0500
committerMike Snitzer <snitzer@redhat.com>2015-02-09 13:06:47 -0500
commite5863d9ad754926e7d3f38b43ac8bd48ef73b097 (patch)
tree0e4d75672884b7dc93296beea8ddf3833b4d7f38 /drivers/md/dm-table.c
parent466d89a6bcd500f64896b514f78b32e8d0b0303a (diff)
downloadlinux-e5863d9ad754926e7d3f38b43ac8bd48ef73b097.tar.bz2
dm: allocate requests in target when stacking on blk-mq devices
For blk-mq request-based DM the responsibility of allocating a cloned request is transfered from DM core to the target type. Doing so enables the cloned request to be allocated from the appropriate blk-mq request_queue's pool (only the DM target, e.g. multipath, can know which block device to send a given cloned request to). Care was taken to preserve compatibility with old-style block request completion that requires request-based DM _not_ acquire the clone request's queue lock in the completion path. As such, there are now 2 different request-based DM target_type interfaces: 1) the original .map_rq() interface will continue to be used for non-blk-mq devices -- the preallocated clone request is passed in from DM core. 2) a new .clone_and_map_rq() and .release_clone_rq() will be used for blk-mq devices -- blk_get_request() and blk_put_request() are used respectively from these hooks. dm_table_set_type() was updated to detect if the request-based target is being stacked on blk-mq devices, if so DM_TYPE_MQ_REQUEST_BASED is set. DM core disallows switching the DM table's type after it is set. This means that there is no mixing of non-blk-mq and blk-mq devices within the same request-based DM table. [This patch was started by Keith and later heavily modified by Mike] Tested-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-table.c')
-rw-r--r--drivers/md/dm-table.c34
1 files changed, 29 insertions, 5 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 3afae9e062f8..2d7e373955f3 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -827,6 +827,7 @@ static int dm_table_set_type(struct dm_table *t)
{
unsigned i;
unsigned bio_based = 0, request_based = 0, hybrid = 0;
+ bool use_blk_mq = false;
struct dm_target *tgt;
struct dm_dev_internal *dd;
struct list_head *devices;
@@ -872,11 +873,26 @@ static int dm_table_set_type(struct dm_table *t)
/* Non-request-stackable devices can't be used for request-based dm */
devices = dm_table_get_devices(t);
list_for_each_entry(dd, devices, list) {
- if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev->bdev))) {
- DMWARN("table load rejected: including"
- " non-request-stackable devices");
+ struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
+
+ if (!blk_queue_stackable(q)) {
+ DMERR("table load rejected: including"
+ " non-request-stackable devices");
return -EINVAL;
}
+
+ if (q->mq_ops)
+ use_blk_mq = true;
+ }
+
+ if (use_blk_mq) {
+ /* verify _all_ devices in the table are blk-mq devices */
+ list_for_each_entry(dd, devices, list)
+ if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
+ DMERR("table load rejected: not all devices"
+ " are blk-mq request-stackable");
+ return -EINVAL;
+ }
}
/*
@@ -890,7 +906,7 @@ static int dm_table_set_type(struct dm_table *t)
return -EINVAL;
}
- t->type = DM_TYPE_REQUEST_BASED;
+ t->type = !use_blk_mq ? DM_TYPE_REQUEST_BASED : DM_TYPE_MQ_REQUEST_BASED;
return 0;
}
@@ -907,7 +923,15 @@ struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
bool dm_table_request_based(struct dm_table *t)
{
- return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
+ unsigned table_type = dm_table_get_type(t);
+
+ return (table_type == DM_TYPE_REQUEST_BASED ||
+ table_type == DM_TYPE_MQ_REQUEST_BASED);
+}
+
+bool dm_table_mq_request_based(struct dm_table *t)
+{
+ return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
}
static int dm_table_alloc_md_mempools(struct dm_table *t)