blk-mq: allow the hctx cpu hotplug notifier to return errors

Prepare this for the next patch which adds more smarts in the
plugging logic, so that we can save some memory.

Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index ef7ed5e95d6d..5a3683fc5bdb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1196,8 +1196,8 @@ void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx *hctx,
 }
 EXPORT_SYMBOL(blk_mq_free_single_hw_queue);
 
-static void blk_mq_hctx_notify(void *data, unsigned long action,
-                               unsigned int cpu)
+static int blk_mq_hctx_notify(void *data, unsigned long action,
+                              unsigned int cpu)
 {
         struct blk_mq_hw_ctx *hctx = data;
         struct request_queue *q = hctx->queue;
@@ -1205,7 +1205,7 @@ static void blk_mq_hctx_notify(void *data, unsigned long action,
         LIST_HEAD(tmp);
 
         if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
-                return;
+                return NOTIFY_OK;
 
         /*
          * Move ctx entries to new CPU, if this one is going away.
@@ -1220,7 +1220,7 @@ static void blk_mq_hctx_notify(void *data, unsigned long action,
         spin_unlock(&ctx->lock);
 
         if (list_empty(&tmp))
-                return;
+                return NOTIFY_OK;
 
         ctx = blk_mq_get_ctx(q);
         spin_lock(&ctx->lock);
@@ -1240,6 +1240,7 @@ static void blk_mq_hctx_notify(void *data, unsigned long action,
 
         blk_mq_run_hw_queue(hctx, true);
         blk_mq_put_ctx(ctx);
+        return NOTIFY_OK;
 }
 
 static void blk_mq_free_rq_map(struct blk_mq_tag_set *set,