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authorNick Piggin <npiggin@suse.de>2008-04-29 14:48:33 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-04-29 14:48:33 +0200
commit75ad23bc0fcb4f992a5d06982bf0857ab1738e9e (patch)
tree8668ef63b1f420252ae41aed9e13737d49fd8054 /drivers/md
parentblock: add dma alignment and padding support to blk_rq_map_kern (diff)
downloadlinux-dev-75ad23bc0fcb4f992a5d06982bf0857ab1738e9e.tar.xz
linux-dev-75ad23bc0fcb4f992a5d06982bf0857ab1738e9e.zip
block: make queue flags non-atomic
We can save some atomic ops in the IO path, if we clearly define the rules of how to modify the queue flags. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to '')
-rw-r--r--drivers/md/dm-table.c7
-rw-r--r--drivers/md/md.c3
2 files changed, 7 insertions, 3 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 51be53344214..73326e7c54bf 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -873,10 +873,13 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q)
q->max_hw_sectors = t->limits.max_hw_sectors;
q->seg_boundary_mask = t->limits.seg_boundary_mask;
q->bounce_pfn = t->limits.bounce_pfn;
+ /* XXX: the below will probably go bug. must ensure there can be no
+ * concurrency on queue_flags, and use the unlocked versions...
+ */
if (t->limits.no_cluster)
- q->queue_flags &= ~(1 << QUEUE_FLAG_CLUSTER);
+ queue_flag_clear(QUEUE_FLAG_CLUSTER, q);
else
- q->queue_flags |= (1 << QUEUE_FLAG_CLUSTER);
+ queue_flag_set(QUEUE_FLAG_CLUSTER, q);
}
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 87620b705bee..acd716b657b8 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -282,7 +282,8 @@ static mddev_t * mddev_find(dev_t unit)
kfree(new);
return NULL;
}
- set_bit(QUEUE_FLAG_CLUSTER, &new->queue->queue_flags);
+ /* Can be unlocked because the queue is new: no concurrency */
+ queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, new->queue);
blk_queue_make_request(new->queue, md_fail_request);