diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 61057b7d..98f87fe 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -151,7 +151,10 @@
 			struct page *src_page, struct page *dest_page,
 			gfp_t gfp_flags)
 {
-	u8 xts_tweak[FS_XTS_TWEAK_SIZE];
+	struct {
+		__le64 index;
+		u8 padding[FS_XTS_TWEAK_SIZE - sizeof(__le64)];
+	} xts_tweak;
 	struct skcipher_request *req = NULL;
 	DECLARE_FS_COMPLETION_RESULT(ecr);
 	struct scatterlist dst, src;
@@ -171,17 +174,15 @@
 		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
 		page_crypt_complete, &ecr);
 
-	BUILD_BUG_ON(FS_XTS_TWEAK_SIZE < sizeof(index));
-	memcpy(xts_tweak, &index, sizeof(index));
-	memset(&xts_tweak[sizeof(index)], 0,
-			FS_XTS_TWEAK_SIZE - sizeof(index));
+	BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE);
+	xts_tweak.index = cpu_to_le64(index);
+	memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));
 
 	sg_init_table(&dst, 1);
 	sg_set_page(&dst, dest_page, PAGE_SIZE, 0);
 	sg_init_table(&src, 1);
 	sg_set_page(&src, src_page, PAGE_SIZE, 0);
-	skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE,
-					xts_tweak);
+	skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak);
 	if (rw == FS_DECRYPT)
 		res = crypto_skcipher_decrypt(req);
 	else