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>
 {
        WARN_ON_ONCE(q->mq_ops);
 
-       q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, q->cmd_size);
+       q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, q->cmd_size, GFP_KERNEL);
        if (!q->fq)
                return -ENOMEM;
 
 
 EXPORT_SYMBOL(blkdev_issue_flush);
 
 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
-               int node, int cmd_size)
+               int node, int cmd_size, gfp_t flags)
 {
        struct blk_flush_queue *fq;
        int rq_sz = sizeof(struct request);
 
-       fq = kzalloc_node(sizeof(*fq), GFP_KERNEL, node);
+       fq = kzalloc_node(sizeof(*fq), flags, node);
        if (!fq)
                goto fail;
 
                spin_lock_init(&fq->mq_flush_lock);
 
        rq_sz = round_up(rq_sz + cmd_size, cache_line_size());
-       fq->flush_rq = kzalloc_node(rq_sz, GFP_KERNEL, node);
+       fq->flush_rq = kzalloc_node(rq_sz, flags, node);
        if (!fq->flush_rq)
                goto fail_rq;
 
 
         * 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;
            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;
 
 
                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;
 
 }
 
 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
-               int node, int cmd_size);
+               int node, int cmd_size, gfp_t flags);
 void blk_free_flush_queue(struct blk_flush_queue *q);
 
 int blk_init_rl(struct request_list *rl, struct request_queue *q,