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-rw-r--r--block/blk-mq.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5629f18b51bd..ab88ff3314a7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1996,7 +1996,8 @@ static void blk_mq_exit_hctx(struct request_queue *q,
{
blk_mq_debugfs_unregister_hctx(hctx);
- blk_mq_tag_idle(hctx);
+ if (blk_mq_hw_queue_mapped(hctx))
+ blk_mq_tag_idle(hctx);
if (set->ops->exit_request)
set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
@@ -2388,6 +2389,9 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
blk_mq_sysfs_unregister(q);
+
+ /* protect against switching io scheduler */
+ mutex_lock(&q->sysfs_lock);
for (i = 0; i < set->nr_hw_queues; i++) {
int node;
@@ -2432,6 +2436,7 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
}
}
q->nr_hw_queues = i;
+ mutex_unlock(&q->sysfs_lock);
blk_mq_sysfs_register(q);
}
@@ -2603,9 +2608,27 @@ static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
{
- if (set->ops->map_queues)
+ if (set->ops->map_queues) {
+ int cpu;
+ /*
+ * transport .map_queues is usually done in the following
+ * way:
+ *
+ * for (queue = 0; queue < set->nr_hw_queues; queue++) {
+ * mask = get_cpu_mask(queue)
+ * for_each_cpu(cpu, mask)
+ * set->mq_map[cpu] = queue;
+ * }
+ *
+ * When we need to remap, the table has to be cleared for
+ * killing stale mapping since one CPU may not be mapped
+ * to any hw queue.
+ */
+ for_each_possible_cpu(cpu)
+ set->mq_map[cpu] = 0;
+
return set->ops->map_queues(set);
- else
+ } else
return blk_mq_map_queues(set);
}