linux-kernel - [PATCH] crypto: skcipher - Realign struct skcipher

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Message-ID: <20250411192053.461263-2-thorsten.blum@linux.dev>
Date: Fri, 11 Apr 2025 21:20:51 +0200
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Herbert Xu <herbert@...dor.apana.org.au>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Biggers <ebiggers@...gle.com>
Cc: Thorsten Blum <thorsten.blum@...ux.dev>,
	linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] crypto: skcipher - Realign struct skcipher_walk to save 8 bytes

Reduce skcipher_walk's struct size by 8 bytes by realigning its members.

pahole output before:

  /* size: 120, cachelines: 2, members: 13 */
  /* sum members: 108, holes: 2, sum holes: 8 */
  /* padding: 4 */
  /* last cacheline: 56 bytes */

and after:

  /* size: 112, cachelines: 2, members: 13 */
  /* padding: 4 */
  /* last cacheline: 48 bytes */

No functional changes intended.

Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
---
 include/crypto/internal/skcipher.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/crypto/internal/skcipher.h b/include/crypto/internal/skcipher.h
index a958ab0636ad..0cad8e7364c8 100644
--- a/include/crypto/internal/skcipher.h
+++ b/include/crypto/internal/skcipher.h
@@ -67,8 +67,6 @@ struct skcipher_walk {
 		struct scatter_walk in;
 	};
 
-	unsigned int nbytes;
-
 	union {
 		/* Virtual address of the destination. */
 		struct {
@@ -81,6 +79,7 @@ struct skcipher_walk {
 		struct scatter_walk out;
 	};
 
+	unsigned int nbytes;
 	unsigned int total;
 
 	u8 *page;
-- 
2.49.0