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 <[email protected]> Tested-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
dedewu6 · Mar 8, 2017 · 7ea5fe3 · 7ea5fe3
1 parent 737f98c
commit 7ea5fe3
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Showing 3 changed files with 20 additions and 8 deletions.
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
@@ -242,24 +242,18 @@ 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);
 	}
 
 	blk_mq_debugfs_unregister_hctxs(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
@@ -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
@@ -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);