commit 5b202853ffbc54b29f23c4b1b5f3948efab489a2
author Jianchao Wang <jianchao.w.wang@oracle.com> Fri Oct 12 18:07:26 2018 +0800
committer Jens Axboe <axboe@kernel.dk> Sat Oct 13 15:42:01 2018 -0600
tree 115c95fa117934258563e7c6530e94153651a4dc
parent 477e19dedc9d3e1f4443a1d4ae00572a988120ea

blk-mq: change gfp flags to GFP_NOIO in blk_mq_realloc_hw_ctxs

blk_mq_realloc_hw_ctxs could be invoked during update hw queues.
At the momemt, IO is blocked. Change the gfp flags from GFP_KERNEL
to GFP_NOIO to avoid forever hang during memory allocation in
blk_mq_realloc_hw_ctxs.

Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 99a72c6..6b73446 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2210,12 +2210,12 @@ static int blk_mq_init_hctx(struct request_queue *q,
 	 * runtime
 	 */
 	hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
-					GFP_KERNEL, node);
+			GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, node);
 	if (!hctx->ctxs)
 		goto unregister_cpu_notifier;
 
-	if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), GFP_KERNEL,
-			      node))
+	if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
+				GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, node))
 		goto free_ctxs;
 
 	hctx->nr_ctx = 0;
@@ -2228,7 +2228,8 @@ static int blk_mq_init_hctx(struct request_queue *q,
 	    set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
 		goto free_bitmap;
 
-	hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size);
+	hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size,
+			GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
 	if (!hctx->fq)
 		goto exit_hctx;
 
@@ -2536,12 +2537,14 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
 
 		node = blk_mq_hw_queue_to_node(q->mq_map, i);
 		hctxs[i] = kzalloc_node(blk_mq_hw_ctx_size(set),
-					GFP_KERNEL, node);
+				GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
+				node);
 		if (!hctxs[i])
 			break;
 
-		if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL,
-						node)) {
+		if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask,
+					GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
+					node)) {
 			kfree(hctxs[i]);
 			hctxs[i] = NULL;
 			break;