Make blk_crypto_split_bio_if_needed() respect
bio_required_sector_alignment() when calling bio_split(). Without this,
blk-crypto-fallback could possibly split a bio in the middle of a data
unit, and the resulting bios can no longer be encrypted (since encryption
can only be done on complete crypto data units).

Signed-off-by: Satya Tangirala <redacted>
---
 block/blk-crypto-fallback.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index c322176a1e09..85c813ef670b 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c

@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/random.h>
 
+#include "blk.h"
 #include "blk-crypto-internal.h"
 
 static unsigned int num_prealloc_bounce_pg = 32;

@@ -225,6 +226,8 @@ static bool blk_crypto_split_bio_if_needed(struct bio **bio_ptr)
 	if (num_sectors < bio_sectors(bio)) {
 		struct bio *split_bio;
 
+		num_sectors = round_down(num_sectors,
+					 bio_required_sector_alignment(bio));
 		split_bio = bio_split(bio, num_sectors, GFP_NOIO,
 				      &crypto_bio_split);
 		if (!split_bio) {

--