1 files changed, 38 insertions, 3 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0dc9e341c2a7..c3621453ad87 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2042,6 +2042,13 @@ static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
 
 	seqcount_init(&rq->gstate_seq);
 	u64_stats_init(&rq->aborted_gstate_sync);
+	/*
+	 * start gstate with gen 1 instead of 0, otherwise it will be equal
+	 * to aborted_gstate, and be identified timed out by
+	 * blk_mq_terminate_expired.
+	 */
+	WRITE_ONCE(rq->gstate, MQ_RQ_GEN_INC);
+
 	return 0;
 }
 
@@ -2329,7 +2336,7 @@ static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
 
 static void blk_mq_map_swqueue(struct request_queue *q)
 {
-	unsigned int i;
+	unsigned int i, hctx_idx;
 	struct blk_mq_hw_ctx *hctx;
 	struct blk_mq_ctx *ctx;
 	struct blk_mq_tag_set *set = q->tag_set;
@@ -2346,8 +2353,23 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 
 	/*
 	 * Map software to hardware queues.
+	 *
+	 * If the cpu isn't present, the cpu is mapped to first hctx.
 	 */
 	for_each_possible_cpu(i) {
+		hctx_idx = q->mq_map[i];
+		/* unmapped hw queue can be remapped after CPU topo changed */
+		if (!set->tags[hctx_idx] &&
+		    !__blk_mq_alloc_rq_map(set, hctx_idx)) {
+			/*
+			 * If tags initialization fail for some hctx,
+			 * that hctx won't be brought online.  In this
+			 * case, remap the current ctx to hctx[0] which
+			 * is guaranteed to always have tags allocated
+			 */
+			q->mq_map[i] = 0;
+		}
+
 		ctx = per_cpu_ptr(q->queue_ctx, i);
 		hctx = blk_mq_map_queue(q, i);
 
@@ -2359,8 +2381,21 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 	mutex_unlock(&q->sysfs_lock);
 
 	queue_for_each_hw_ctx(q, hctx, i) {
-		/* every hctx should get mapped by at least one CPU */
-		WARN_ON(!hctx->nr_ctx);
+		/*
+		 * If no software queues are mapped to this hardware queue,
+		 * disable it and free the request entries.
+		 */
+		if (!hctx->nr_ctx) {
+			/* Never unmap queue 0.  We need it as a
+			 * fallback in case of a new remap fails
+			 * allocation
+			 */
+			if (i && set->tags[i])
+				blk_mq_free_map_and_requests(set, i);
+
+			hctx->tags = NULL;
+			continue;
+		}
 
 		hctx->tags = set->tags[i];
 		WARN_ON(!hctx->tags);