blk-mq: fix sysfs registration/unregistration race

[karo-tx-linux.git] / block / blk-mq-sysfs.c

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 279c5d674edf3cb38627feb360eb745194eecd4e..189f5ae6522af50093d3e4225bd05df31b7edc87 100644 (file)
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -343,7 +343,7 @@ static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
        struct blk_mq_ctx *ctx;
        int i;
 
-       if (!hctx->nr_ctx || !(hctx->flags & BLK_MQ_F_SYSFS_UP))
+       if (!hctx->nr_ctx)
                return;
 
        hctx_for_each_ctx(hctx, ctx, i)
@@ -358,7 +358,7 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
        struct blk_mq_ctx *ctx;
        int i, ret;
 
-       if (!hctx->nr_ctx || !(hctx->flags & BLK_MQ_F_SYSFS_UP))
+       if (!hctx->nr_ctx)
                return 0;
 
        ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", hctx->queue_num);
@@ -381,6 +381,8 @@ void blk_mq_unregister_disk(struct gendisk *disk)
        struct blk_mq_ctx *ctx;
        int i, j;
 
+       blk_mq_disable_hotplug();
+
        queue_for_each_hw_ctx(q, hctx, i) {
                blk_mq_unregister_hctx(hctx);
 
@@ -395,6 +397,9 @@ void blk_mq_unregister_disk(struct gendisk *disk)
        kobject_put(&q->mq_kobj);
 
        kobject_put(&disk_to_dev(disk)->kobj);
+
+       q->mq_sysfs_init_done = false;
+       blk_mq_enable_hotplug();
 }
 
 static void blk_mq_sysfs_init(struct request_queue *q)
@@ -425,27 +430,30 @@ int blk_mq_register_disk(struct gendisk *disk)
        struct blk_mq_hw_ctx *hctx;
        int ret, i;
 
+       blk_mq_disable_hotplug();
+
        blk_mq_sysfs_init(q);
 
        ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
        if (ret < 0)
-               return ret;
+               goto out;
 
        kobject_uevent(&q->mq_kobj, KOBJ_ADD);
 
        queue_for_each_hw_ctx(q, hctx, i) {
-               hctx->flags |= BLK_MQ_F_SYSFS_UP;
                ret = blk_mq_register_hctx(hctx);
                if (ret)
                        break;
        }
 
-       if (ret) {
+       if (ret)
                blk_mq_unregister_disk(disk);
-               return ret;
-       }
+       else
+               q->mq_sysfs_init_done = true;
+out:
+       blk_mq_enable_hotplug();
 
-       return 0;
+       return ret;
 }
 EXPORT_SYMBOL_GPL(blk_mq_register_disk);
 
@@ -454,6 +462,9 @@ void blk_mq_sysfs_unregister(struct request_queue *q)
        struct blk_mq_hw_ctx *hctx;
        int i;
 
+       if (!q->mq_sysfs_init_done)
+               return;
+
        queue_for_each_hw_ctx(q, hctx, i)
                blk_mq_unregister_hctx(hctx);
 }
@@ -463,6 +474,9 @@ int blk_mq_sysfs_register(struct request_queue *q)
        struct blk_mq_hw_ctx *hctx;
        int i, ret = 0;
 
+       if (!q->mq_sysfs_init_done)
+               return ret;
+
        queue_for_each_hw_ctx(q, hctx, i) {
                ret = blk_mq_register_hctx(hctx);
                if (ret)