genhd: Add helper put_disk_and_module()

Add a proper counterpart to get_disk_and_module() -
put_disk_and_module(). Currently it is opencoded in several places.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 4117524..c2033a2 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -812,7 +812,6 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
        struct gendisk *disk;
        struct request_queue *q;
        struct blkcg_gq *blkg;
-       struct module *owner;
        unsigned int major, minor;
        int key_len, part, ret;
        char *body;
@@ -904,9 +903,7 @@ fail_unlock:
        spin_unlock_irq(q->queue_lock);
        rcu_read_unlock();
 fail:
-       owner = disk->fops->owner;
-       put_disk(disk);
-       module_put(owner);
+       put_disk_and_module(disk);
        /*
         * If queue was bypassing, we should retry.  Do so after a
         * short msleep().  It isn't strictly necessary but queue
@@ -931,13 +928,9 @@ EXPORT_SYMBOL_GPL(blkg_conf_prep);
 void blkg_conf_finish(struct blkg_conf_ctx *ctx)
        __releases(ctx->disk->queue->queue_lock) __releases(rcu)
 {
-       struct module *owner;
-
        spin_unlock_irq(ctx->disk->queue->queue_lock);
        rcu_read_unlock();
-       owner = ctx->disk->fops->owner;
-       put_disk(ctx->disk);
-       module_put(owner);
+       put_disk_and_module(ctx->disk);
 }
 EXPORT_SYMBOL_GPL(blkg_conf_finish);
 

diff --git a/block/genhd.c b/block/genhd.c
index 21b2843..4c05904 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -817,10 +817,7 @@ struct gendisk *get_gendisk(dev_t devt, int *partno)
        }
 
        if (disk && unlikely(disk->flags & GENHD_FL_HIDDEN)) {
-               struct module *owner = disk->fops->owner;
-
-               put_disk(disk);
-               module_put(owner);
+               put_disk_and_module(disk);
                disk = NULL;
        }
        return disk;
@@ -1483,6 +1480,21 @@ void put_disk(struct gendisk *disk)
 }
 EXPORT_SYMBOL(put_disk);
 
+/*
+ * This is a counterpart of get_disk_and_module() and thus also of
+ * get_gendisk().
+ */
+void put_disk_and_module(struct gendisk *disk)
+{
+       if (disk) {
+               struct module *owner = disk->fops->owner;
+
+               put_disk(disk);
+               module_put(owner);
+       }
+}
+EXPORT_SYMBOL(put_disk_and_module);
+
 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
 {
        char event[] = "DISK_RO=1";

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 4a181fc..1dbbf84 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1111,8 +1111,7 @@ static struct block_device *bd_start_claiming(struct block_device *bdev,
        else
                whole = bdgrab(bdev);
 
-       module_put(disk->fops->owner);
-       put_disk(disk);
+       put_disk_and_module(disk);
        if (!whole)
                return ERR_PTR(-ENOMEM);
 
@@ -1407,7 +1406,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 {
        struct gendisk *disk;
-       struct module *owner;
        int ret;
        int partno;
        int perm = 0;
@@ -1433,7 +1431,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
        disk = get_gendisk(bdev->bd_dev, &partno);
        if (!disk)
                goto out;
-       owner = disk->fops->owner;
 
        disk_block_events(disk);
        mutex_lock_nested(&bdev->bd_mutex, for_part);
@@ -1463,8 +1460,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                                        bdev->bd_queue = NULL;
                                        mutex_unlock(&bdev->bd_mutex);
                                        disk_unblock_events(disk);
-                                       put_disk(disk);
-                                       module_put(owner);
+                                       put_disk_and_module(disk);
                                        goto restart;
                                }
                        }
@@ -1525,8 +1521,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                                goto out_unlock_bdev;
                }
                /* only one opener holds refs to the module and disk */
-               put_disk(disk);
-               module_put(owner);
+               put_disk_and_module(disk);
        }
        bdev->bd_openers++;
        if (for_part)
@@ -1546,8 +1541,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
  out_unlock_bdev:
        mutex_unlock(&bdev->bd_mutex);
        disk_unblock_events(disk);
-       put_disk(disk);
-       module_put(owner);
+       put_disk_and_module(disk);
  out:
        bdput(bdev);
 
@@ -1770,8 +1764,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
                        disk->fops->release(disk, mode);
        }
        if (!bdev->bd_openers) {
-               struct module *owner = disk->fops->owner;
-
                disk_put_part(bdev->bd_part);
                bdev->bd_part = NULL;
                bdev->bd_disk = NULL;
@@ -1779,8 +1771,7 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
                        victim = bdev->bd_contains;
                bdev->bd_contains = NULL;
 
-               put_disk(disk);
-               module_put(owner);
+               put_disk_and_module(disk);
        }
        mutex_unlock(&bdev->bd_mutex);
        bdput(bdev);

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 8e11b93..7f5906f 100644 (file)
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -602,6 +602,7 @@ extern void printk_all_partitions(void);
 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
 extern struct kobject *get_disk_and_module(struct gendisk *disk);
 extern void put_disk(struct gendisk *disk);
+extern void put_disk_and_module(struct gendisk *disk);
 extern void blk_register_region(dev_t devt, unsigned long range,
                        struct module *module,
                        struct kobject *(*probe)(dev_t, int *, void *),