From fb541ca4c36500b7b1d1a4def992059d9af56f14 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 29 Nov 2022 14:32:53 +0100
Subject: [PATCH] md: remove lock_bdev / unlock_bdev
Git-commit: fb541ca4c36500b7b1d1a4def992059d9af56f14
Patch-mainline: v6.2-rc1
References: git-fixes

These wrappers for blkdev_get / blkdev_put just horribly confuse the
code with their odd naming.  Remove them and improve the error unwinding
in md_import_device with the now folded code.

(Coly Li: rebased for Linux v4.12 based SUSE kernel)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/md.c |   63 +++++++++++++++++++-------------------------------------
 1 file changed, 22 insertions(+), 41 deletions(-)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2446,34 +2446,6 @@ static void unbind_rdev_from_array(struc
 	queue_work(md_rdev_misc_wq, &rdev->del_work);
 }
 
-/*
- * prevent the device from being mounted, repartitioned or
- * otherwise reused by a RAID array (or any other kernel
- * subsystem), by bd_claiming the device.
- */
-static int lock_rdev(struct md_rdev *rdev, dev_t dev, int shared)
-{
-	int err = 0;
-	struct block_device *bdev;
-	char b[BDEVNAME_SIZE];
-
-	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
-				 shared ? (struct md_rdev *)lock_rdev : rdev);
-	if (IS_ERR(bdev)) {
-		pr_warn("md: could not open %s.\n", __bdevname(dev, b));
-		return PTR_ERR(bdev);
-	}
-	rdev->bdev = bdev;
-	return err;
-}
-
-static void unlock_rdev(struct md_rdev *rdev)
-{
-	struct block_device *bdev = rdev->bdev;
-	rdev->bdev = NULL;
-	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
-}
-
 void md_autodetect_dev(dev_t dev);
 
 static void export_rdev(struct md_rdev *rdev)
@@ -2486,7 +2458,8 @@ static void export_rdev(struct md_rdev *
 	if (test_bit(AutoDetected, &rdev->flags))
 		md_autodetect_dev(rdev->bdev->bd_dev);
 #endif
-	unlock_rdev(rdev);
+	blkdev_put(rdev->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+	rdev->bdev = NULL;
 	kobject_put(&rdev->kobj);
 }
 
@@ -3627,9 +3600,10 @@ EXPORT_SYMBOL_GPL(md_rdev_init);
 static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor)
 {
 	char b[BDEVNAME_SIZE];
-	int err;
+	static struct md_rdev *claim_rdev; /* just for claiming the bdev */
 	struct md_rdev *rdev;
 	sector_t size;
+	int err;
 
 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
 	if (!rdev)
@@ -3637,14 +3611,20 @@ static struct md_rdev *md_import_device(
 
 	err = md_rdev_init(rdev);
 	if (err)
-		goto abort_free;
+		goto out_free_rdev;
 	err = alloc_disk_sb(rdev);
 	if (err)
-		goto abort_free;
+		goto out_clear_rdev;
 
-	err = lock_rdev(rdev, newdev, super_format == -2);
-	if (err)
-		goto abort_free;
+	rdev->bdev = blkdev_get_by_dev(newdev,
+			FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+			super_format == -2 ? claim_rdev : rdev);
+	if (IS_ERR(rdev->bdev)) {
+		pr_warn("md: could not open device unknown-block(%u,%u).\n",
+			MAJOR(newdev), MINOR(newdev));
+		err = PTR_ERR(rdev->bdev);
+		goto out_clear_rdev;
+	}
 
 	kobject_init(&rdev->kobj, &rdev_ktype);
 
@@ -3653,7 +3633,7 @@ static struct md_rdev *md_import_device(
 		pr_warn("md: %s has zero or unknown size, marking faulty!\n",
 			bdevname(rdev->bdev,b));
 		err = -EINVAL;
-		goto abort_free;
+		goto out_blkdev_put;
 	}
 
 	if (super_format >= 0) {
@@ -3663,21 +3643,22 @@ static struct md_rdev *md_import_device(
 			pr_warn("md: %s does not have a valid v%d.%d superblock, not importing!\n",
 				bdevname(rdev->bdev,b),
 				super_format, super_minor);
-			goto abort_free;
+			goto out_blkdev_put;
 		}
 		if (err < 0) {
 			pr_warn("md: could not read %s's sb, not importing!\n",
 				bdevname(rdev->bdev,b));
-			goto abort_free;
+			goto out_blkdev_put;
 		}
 	}
 
 	return rdev;
 
-abort_free:
-	if (rdev->bdev)
-		unlock_rdev(rdev);
+out_blkdev_put:
+	blkdev_put(rdev->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+out_clear_rdev:
 	md_rdev_clear(rdev);
+out_free_rdev:
 	kfree(rdev);
 	return ERR_PTR(err);
 }