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authorMing Lei <ming.lei@canonical.com>2015-04-21 10:00:20 +0800
committerSasha Levin <sasha.levin@oracle.com>2015-08-06 14:49:50 -0400
commitdf0e5109cfea25f842bf99f567aac20ac9ef78fe (patch)
treef1541af96a8d8f41d01adf2e1b83fb7fab23a597
parentbda69f1aaee53837ba22e2ea149219dff486f542 (diff)
blk-mq: fix CPU hotplug handling
[ Upstream commit 2a34c0872adf252f23a6fef2d051a169ac796cef ] hctx->tags has to be set as NULL in case that it is to be unmapped no matter if set->tags[hctx->queue_num] is NULL or not in blk_mq_map_swqueue() because shared tags can be freed already from another request queue. The same situation has to be considered during handling CPU online too. Unmapped hw queue can be remapped after CPU topo is changed, so we need to allocate tags for the hw queue in blk_mq_map_swqueue(). Then tags allocation for hw queue can be removed in hctx cpu online notifier, and it is reasonable to do that after mapping is updated. Cc: <stable@vger.kernel.org> Reported-by: Dongsu Park <dongsu.park@profitbricks.com> Tested-by: Dongsu Park <dongsu.park@profitbricks.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--block/blk-mq.c34
1 files changed, 13 insertions, 21 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 849479debac3..691959ecb80f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1473,22 +1473,6 @@ static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu)
return NOTIFY_OK;
}
-static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx *hctx, int cpu)
-{
- struct request_queue *q = hctx->queue;
- struct blk_mq_tag_set *set = q->tag_set;
-
- if (set->tags[hctx->queue_num])
- return NOTIFY_OK;
-
- set->tags[hctx->queue_num] = blk_mq_init_rq_map(set, hctx->queue_num);
- if (!set->tags[hctx->queue_num])
- return NOTIFY_STOP;
-
- hctx->tags = set->tags[hctx->queue_num];
- return NOTIFY_OK;
-}
-
static int blk_mq_hctx_notify(void *data, unsigned long action,
unsigned int cpu)
{
@@ -1496,8 +1480,11 @@ static int blk_mq_hctx_notify(void *data, unsigned long action,
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
return blk_mq_hctx_cpu_offline(hctx, cpu);
- else if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
- return blk_mq_hctx_cpu_online(hctx, cpu);
+
+ /*
+ * In case of CPU online, tags may be reallocated
+ * in blk_mq_map_swqueue() after mapping is updated.
+ */
return NOTIFY_OK;
}
@@ -1682,6 +1669,7 @@ static void blk_mq_map_swqueue(struct request_queue *q)
unsigned int i;
struct blk_mq_hw_ctx *hctx;
struct blk_mq_ctx *ctx;
+ struct blk_mq_tag_set *set = q->tag_set;
queue_for_each_hw_ctx(q, hctx, i) {
cpumask_clear(hctx->cpumask);
@@ -1708,16 +1696,20 @@ static void blk_mq_map_swqueue(struct request_queue *q)
* disable it and free the request entries.
*/
if (!hctx->nr_ctx) {
- struct blk_mq_tag_set *set = q->tag_set;
-
if (set->tags[i]) {
blk_mq_free_rq_map(set, set->tags[i], i);
set->tags[i] = NULL;
- hctx->tags = NULL;
}
+ hctx->tags = NULL;
continue;
}
+ /* unmapped hw queue can be remapped after CPU topo changed */
+ if (!set->tags[i])
+ set->tags[i] = blk_mq_init_rq_map(set, i);
+ hctx->tags = set->tags[i];
+ WARN_ON(!hctx->tags);
+
/*
* Initialize batch roundrobin counts
*/