block: move bd_mutex to struct gendisk

Replace the per-block device bd_mutex with a per-gendisk open_mutex,
thus simplifying locking wherever we deal with partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Link: https://lore.kernel.org/r/20210525061301.2242282-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

4 files changed, 21 insertions, 21 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d58d68f3c7cd..95c570f5923f 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -652,9 +652,9 @@ static void loop_reread_partitions(struct loop_device *lo,
 {
 	int rc;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	rc = bdev_disk_changed(bdev, false);
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	if (rc)
 		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
 			__func__, lo->lo_number, lo->lo_file_name, rc);
@@ -747,7 +747,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 	mutex_unlock(&lo->lo_mutex);
 	/*
 	 * We must drop file reference outside of lo_mutex as dropping
-	 * the file ref can take bd_mutex which creates circular locking
+	 * the file ref can take open_mutex which creates circular locking
 	 * dependency.
 	 */
 	fput(old_file);
@@ -1260,7 +1260,7 @@ out_unlock:
 	mutex_unlock(&lo->lo_mutex);
 	if (partscan) {
 		/*
-		 * bd_mutex has been held already in release path, so don't
+		 * open_mutex has been held already in release path, so don't
 		 * acquire it if this function is called in such case.
 		 *
 		 * If the reread partition isn't from release path, lo_refcnt
@@ -1268,10 +1268,10 @@ out_unlock:
 		 * current holder is released.
 		 */
 		if (!release)
-			mutex_lock(&bdev->bd_mutex);
+			mutex_lock(&bdev->bd_disk->open_mutex);
 		err = bdev_disk_changed(bdev, false);
 		if (!release)
-			mutex_unlock(&bdev->bd_mutex);
+			mutex_unlock(&bdev->bd_disk->open_mutex);
 		if (err)
 			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
 				__func__, lo_number, err);
@@ -1298,7 +1298,7 @@ out_unlock:
 	/*
 	 * Need not hold lo_mutex to fput backing file. Calling fput holding
 	 * lo_mutex triggers a circular lock dependency possibility warning as
-	 * fput can take bd_mutex which is usually taken before lo_mutex.
+	 * fput can take open_mutex which is usually taken before lo_mutex.
 	 */
 	if (filp)
 		fput(filp);
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 10df39a8b18d..f2c1aedcdf5a 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2163,7 +2163,7 @@ static void blkfront_closing(struct blkfront_info *info)
 		return;
 	}
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 
 	if (bdev->bd_openers) {
 		xenbus_dev_error(xbdev, -EBUSY,
@@ -2174,7 +2174,7 @@ static void blkfront_closing(struct blkfront_info *info)
 		xenbus_frontend_closed(xbdev);
 	}
 
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	bdput(bdev);
 }
 
@@ -2531,7 +2531,7 @@ static int blkfront_remove(struct xenbus_device *xbdev)
 	 * isn't closed yet, we let release take care of it.
 	 */
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&disk->open_mutex);
 	info = disk->private_data;
 
 	dev_warn(disk_to_dev(disk),
@@ -2546,7 +2546,7 @@ static int blkfront_remove(struct xenbus_device *xbdev)
 		mutex_unlock(&blkfront_mutex);
 	}
 
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&disk->open_mutex);
 	bdput(bdev);
 
 	return 0;
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 006416cc4969..fcaf2750f68f 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1781,24 +1781,24 @@ static ssize_t reset_store(struct device *dev,
 	zram = dev_to_zram(dev);
 	bdev = zram->disk->part0;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	/* Do not reset an active device or claimed device */
 	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
+		mutex_unlock(&bdev->bd_disk->open_mutex);
 		return -EBUSY;
 	}
 
 	/* From now on, anyone can't open /dev/zram[0-9] */
 	zram->claim = true;
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	/* Make sure all the pending I/O are finished */
 	fsync_bdev(bdev);
 	zram_reset_device(zram);
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	zram->claim = false;
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	return len;
 }
@@ -1808,7 +1808,7 @@ static int zram_open(struct block_device *bdev, fmode_t mode)
 	int ret = 0;
 	struct zram *zram;
 
-	WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
+	WARN_ON(!mutex_is_locked(&bdev->bd_disk->open_mutex));
 
 	zram = bdev->bd_disk->private_data;
 	/* zram was claimed to reset so open request fails */
@@ -1972,14 +1972,14 @@ static int zram_remove(struct zram *zram)
 {
 	struct block_device *bdev = zram->disk->part0;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
+		mutex_unlock(&bdev->bd_disk->open_mutex);
 		return -EBUSY;
 	}
 
 	zram->claim = true;
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	zram_debugfs_unregister(zram);
 
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 419a7e8281ee..74c411911b6e 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -112,7 +112,7 @@ struct zram {
 	/*
 	 * zram is claimed so open request will be failed
 	 */
-	bool claim; /* Protected by bdev->bd_mutex */
+	bool claim; /* Protected by disk->open_mutex */
 	struct file *backing_dev;
 #ifdef CONFIG_ZRAM_WRITEBACK
 	spinlock_t wb_limit_lock;