blk-mq: simplify reallocation of hw ctxs a bit

blk_mq_alloc_and_init_hctx() has already taken reuse into account, so
no need to do it outside, then we can simplify blk_mq_realloc_hw_ctxs().

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220308073219.91173-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5d25abf..64fddb3 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3966,29 +3966,24 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
        /* protect against switching io scheduler  */
        mutex_lock(&q->sysfs_lock);
        for (i = 0; i < set->nr_hw_queues; i++) {
+               int old_node;
                int node = blk_mq_get_hctx_node(set, i);
-               struct blk_mq_hw_ctx *hctx;
+               struct blk_mq_hw_ctx *old_hctx = hctxs[i];
 
-               /*
-                * If the hw queue has been mapped to another numa node,
-                * we need to realloc the hctx. If allocation fails, fallback
-                * to use the previous one.
-                */
-               if (hctxs[i] && (hctxs[i]->numa_node == node))
-                       continue;
+               if (old_hctx) {
+                       old_node = old_hctx->numa_node;
+                       blk_mq_exit_hctx(q, set, old_hctx, i);
+               }
 
-               hctx = blk_mq_alloc_and_init_hctx(set, q, i, node);
-               if (hctx) {
-                       if (hctxs[i])
-                               blk_mq_exit_hctx(q, set, hctxs[i], i);
-                       hctxs[i] = hctx;
-               } else {
-                       if (hctxs[i])
-                               pr_warn("Allocate new hctx on node %d fails,\
-                                               fallback to previous one on node %d\n",
-                                               node, hctxs[i]->numa_node);
-                       else
+               hctxs[i] = blk_mq_alloc_and_init_hctx(set, q, i, node);
+               if (!hctxs[i]) {
+                       if (!old_hctx)
                                break;
+                       pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
+                                       node, old_node);
+                       hctxs[i] = blk_mq_alloc_and_init_hctx(set, q, i,
+                                       old_node);
+                       WARN_ON_ONCE(!hctxs[i]);
                }
        }
        /*