blk-mq: fix sysfs inflight counter

[mirror_ubuntu-bionic-kernel.git] / block / blk-mq-sysfs.c

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index d745ab81033afa8510f6b2d8dbbbdc187693901a..79969c3c234fd9db3f76f2186d3f7080e9f1e321 100644 (file)
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -253,11 +253,11 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
        struct blk_mq_hw_ctx *hctx;
        int i;
 
+       lockdep_assert_held(&q->sysfs_lock);
+
        queue_for_each_hw_ctx(q, hctx, i)
                blk_mq_unregister_hctx(hctx);
 
-       blk_mq_debugfs_unregister_hctxs(q);
-
        kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
        kobject_del(&q->mq_kobj);
        kobject_put(&dev->kobj);
@@ -267,9 +267,9 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 
 void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 {
-       blk_mq_disable_hotplug();
+       mutex_lock(&q->sysfs_lock);
        __blk_mq_unregister_dev(dev, q);
-       blk_mq_enable_hotplug();
+       mutex_unlock(&q->sysfs_lock);
 }
 
 void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
@@ -302,12 +302,13 @@ void blk_mq_sysfs_init(struct request_queue *q)
        }
 }
 
-int blk_mq_register_dev(struct device *dev, struct request_queue *q)
+int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
 {
        struct blk_mq_hw_ctx *hctx;
        int ret, i;
 
-       blk_mq_disable_hotplug();
+       WARN_ON_ONCE(!q->kobj.parent);
+       lockdep_assert_held(&q->sysfs_lock);
 
        ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
        if (ret < 0)
@@ -315,20 +316,34 @@ int blk_mq_register_dev(struct device *dev, struct request_queue *q)
 
        kobject_uevent(&q->mq_kobj, KOBJ_ADD);
 
-       blk_mq_debugfs_register(q, kobject_name(&dev->kobj));
-
        queue_for_each_hw_ctx(q, hctx, i) {
                ret = blk_mq_register_hctx(hctx);
                if (ret)
-                       break;
+                       goto unreg;
        }
 
-       if (ret)
-               __blk_mq_unregister_dev(dev, q);
-       else
-               q->mq_sysfs_init_done = true;
+       q->mq_sysfs_init_done = true;
+
 out:
-       blk_mq_enable_hotplug();
+       return ret;
+
+unreg:
+       while (--i >= 0)
+               blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
+
+       kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
+       kobject_del(&q->mq_kobj);
+       kobject_put(&dev->kobj);
+       return ret;
+}
+
+int blk_mq_register_dev(struct device *dev, struct request_queue *q)
+{
+       int ret;
+
+       mutex_lock(&q->sysfs_lock);
+       ret = __blk_mq_register_dev(dev, q);
+       mutex_unlock(&q->sysfs_lock);
 
        return ret;
 }
@@ -339,13 +354,15 @@ void blk_mq_sysfs_unregister(struct request_queue *q)
        struct blk_mq_hw_ctx *hctx;
        int i;
 
+       mutex_lock(&q->sysfs_lock);
        if (!q->mq_sysfs_init_done)
-               return;
-
-       blk_mq_debugfs_unregister_hctxs(q);
+               goto unlock;
 
        queue_for_each_hw_ctx(q, hctx, i)
                blk_mq_unregister_hctx(hctx);
+
+unlock:
+       mutex_unlock(&q->sysfs_lock);
 }
 
 int blk_mq_sysfs_register(struct request_queue *q)
@@ -353,10 +370,9 @@ int blk_mq_sysfs_register(struct request_queue *q)
        struct blk_mq_hw_ctx *hctx;
        int i, ret = 0;
 
+       mutex_lock(&q->sysfs_lock);
        if (!q->mq_sysfs_init_done)
-               return ret;
-
-       blk_mq_debugfs_register_hctxs(q);
+               goto unlock;
 
        queue_for_each_hw_ctx(q, hctx, i) {
                ret = blk_mq_register_hctx(hctx);
@@ -364,5 +380,8 @@ int blk_mq_sysfs_register(struct request_queue *q)
                        break;
        }
 
+unlock:
+       mutex_unlock(&q->sysfs_lock);
+
        return ret;
 }