blk-mq: make lifetime consitent between q/ctx and its kobject

Currently from kobject view, both q->mq_kobj and ctx->kobj can
be released during one cycle of blk_mq_register_dev() and
blk_mq_unregister_dev(). Actually, sw queue's lifetime is
same with its request queue's, which is covered by request_queue->kobj.

So we don't need to call kobject_put() for the two kinds of
kobject in __blk_mq_unregister_dev(), instead we do that
in release handler of request queue.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 124305407c8015d54d255b48059388c561674237..77fb238af2be9be63671f08e6d886660437b0485 100644 (file)
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -242,15 +242,11 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
 static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 {
        struct blk_mq_hw_ctx *hctx;
-       struct blk_mq_ctx *ctx;
-       int i, j;
+       int i;
 
        queue_for_each_hw_ctx(q, hctx, i) {
                blk_mq_unregister_hctx(hctx);
 
-               hctx_for_each_ctx(hctx, ctx, j)
-                       kobject_put(&ctx->kobj);
-
                kobject_put(&hctx->kobj);
        }
 
@@ -258,8 +254,6 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 
        kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
        kobject_del(&q->mq_kobj);
-       kobject_put(&q->mq_kobj);
-
        kobject_put(&dev->kobj);
 
        q->mq_sysfs_init_done = false;
@@ -277,6 +271,18 @@ void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
        kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
 }
 
+void blk_mq_sysfs_deinit(struct request_queue *q)
+{
+       struct blk_mq_ctx *ctx;
+       int cpu;
+
+       for_each_possible_cpu(cpu) {
+               ctx = per_cpu_ptr(q->queue_ctx, cpu);
+               kobject_put(&ctx->kobj);
+       }
+       kobject_put(&q->mq_kobj);
+}
+
 void blk_mq_sysfs_init(struct request_queue *q)
 {
        struct blk_mq_ctx *ctx;

diff --git a/block/blk-mq.c b/block/blk-mq.c
index ed4b55176cddaedbb08f0101ca7040fea4d18cfd..b985c236f50f5431f45e2089e5c1ec656ff9c932 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2264,7 +2264,12 @@ void blk_mq_release(struct request_queue *q)
 
        kfree(q->queue_hw_ctx);
 
-       /* ctx kobj stays in queue_ctx */
+       /*
+        * release .mq_kobj and sw queue's kobject now because
+        * both share lifetime with request queue.
+        */
+       blk_mq_sysfs_deinit(q);
+
        free_percpu(q->queue_ctx);
 }
 

diff --git a/block/blk-mq.h b/block/blk-mq.h
index ad8bfd7473ef7ebdf4142dac6a18095e91553cca..b79f9a7d8cf62010dd9a91d3b271e5d2474cb836 100644 (file)
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -78,6 +78,7 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
  * sysfs helpers
  */
 extern void blk_mq_sysfs_init(struct request_queue *q);
+extern void blk_mq_sysfs_deinit(struct request_queue *q);
 extern int blk_mq_sysfs_register(struct request_queue *q);
 extern void blk_mq_sysfs_unregister(struct request_queue *q);
 extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);