[PATCH 4.19 014/338] block: Add a helper to validate the block size

[Greg Kroah-Hartman]

From: Xie Yongji <xieyongji@xxxxxxxxxxxxx>

commit 570b1cac477643cbf01a45fa5d018430a1fddbce upstream.

There are some duplicated codes to validate the block
size in block drivers. This limitation actually comes
from block layer, so this patch tries to add a new block
layer helper for that.

Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211026144015.188-2-xieyongji@xxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 include/linux/blkdev.h |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -56,6 +56,14 @@ struct blk_stat_callback;
  */
 #define BLKCG_MAX_POLS		5
 
+static inline int blk_validate_block_size(unsigned int bsize)
+{
+	if (bsize < 512 || bsize > PAGE_SIZE || !is_power_of_2(bsize))
+		return -EINVAL;
+
+	return 0;
+}
+
 typedef void (rq_end_io_fn)(struct request *, blk_status_t);
 
 #define BLK_RL_SYNCFULL		(1U << 0)