block: Deprecate QUEUE_FLAG_CLUSTER and use queue_limits instead
When stacking devices, a request_queue is not always available. This
forced us to have a no_cluster flag in the queue_limits that could be
used as a carrier until the request_queue had been set up for a
metadevice.
There were several problems with that approach. First of all it was up
to the stacking device to remember to set queue flag after stacking had
completed. Also, the queue flag and the queue limits had to be kept in
sync at all times. We got that wrong, which could lead to us issuing
commands that went beyond the max scatterlist limit set by the driver.
The proper fix is to avoid having two flags for tracking the same thing.
We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the
block layer merging functions. The queue_limit 'no_cluster' is turned
into 'cluster' to avoid double negatives and to ease stacking.
Clustering defaults to being enabled as before. The queue flag logic is
removed from the stacking function, and explicitly setting the cluster
flag is no longer necessary in DM and MD.
Reported-by: Ed Lin <ed.lin@promise.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 90267f8..e2da191 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1131,11 +1131,6 @@
*/
q->limits = *limits;
- if (limits->no_cluster)
- queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
- else
- queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);
-
if (!dm_table_supports_discards(t))
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
else
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 84c46a1..52694d2 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4296,9 +4296,6 @@
goto abort;
mddev->queue->queuedata = mddev;
- /* Can be unlocked because the queue is new: no concurrency */
- queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, mddev->queue);
-
blk_queue_make_request(mddev->queue, md_make_request);
disk = alloc_disk(1 << shift);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index eafeeda..9d7ba07 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1642,9 +1642,8 @@
blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
- /* New queue, no concurrency on queue_flags */
if (!shost->use_clustering)
- queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
+ q->limits.cluster = 0;
/*
* set a reasonable default alignment on word boundaries: the