[PATCH 6.6.y 2/3] block2mtd: prevent direct access of bd_inode

[Sasha Levin <sashal@kernel.org>]

From: Yu Kuai <yukuai3@huawei.com>

[ Upstream commit c9600c63a694249100e2bdcbb604c30d8fee2dc7 ]

All we need is size, and that can be obtained via bdev_nr_bytes()

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20240411145346.2516848-11-viro@zeniv.linux.org.uk
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: b5965c422116 ("mtd: block2mtd: Fix divide error when erase_size is zero")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mtd/devices/block2mtd.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index aa44a23ec0451..502c30124aa61 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -269,6 +269,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size,
 	struct bdev_handle *bdev_handle;
 	struct block_device *bdev;
 	struct block2mtd_dev *dev;
+	loff_t size;
 	char *name;
 
 	if (!devname)
@@ -295,7 +296,8 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size,
 		goto err_free_block2mtd;
 	}
 
-	if ((long)bdev->bd_inode->i_size % erase_size) {
+	size = bdev_nr_bytes(bdev);
+	if ((long)size % erase_size) {
 		pr_err("erasesize must be a divisor of device size\n");
 		goto err_free_block2mtd;
 	}
@@ -313,7 +315,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size,
 
 	dev->mtd.name = name;
 
-	dev->mtd.size = bdev->bd_inode->i_size & PAGE_MASK;
+	dev->mtd.size = size & PAGE_MASK;
 	dev->mtd.erasesize = erase_size;
 	dev->mtd.writesize = 1;
 	dev->mtd.writebufsize = PAGE_SIZE;
-- 
2.53.0