From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f53.google.com ([209.85.220.53]:33542 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751470AbaIEW62 (ORCPT ); Fri, 5 Sep 2014 18:58:28 -0400 Received: by mail-pa0-f53.google.com with SMTP id fa1so22695847pad.26 for ; Fri, 05 Sep 2014 15:58:27 -0700 (PDT) From: behanw@converseincode.com To: clm@fb.com, jbacik@fb.com Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Vin=C3=ADcius=20Tinti?= , =?UTF-8?q?Jan-Simon=20M=C3=B6ller?= , Behan Webster , Mark Charlebois Subject: [PATCH v2] btrfs: LLVMLinux: Remove VLAIS Date: Fri, 5 Sep 2014 15:58:21 -0700 Message-Id: <1409957901-28962-1-git-send-email-behanw@converseincode.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: From: Vinícius Tinti Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99 compliant equivalent. This is the original VLAIS struct. struct { struct shash_desc shash; char ctx[crypto_shash_descsize(tfm)]; } desc; This patch instead allocates the appropriate amount of memory using an char array. The new code can be compiled with both gcc and clang. struct shash_desc contains a flexible array member member ctx declared with CRYPTO_MINALIGN_ATTR, so sizeof(struct shash_desc) aligns the beginning of the array declared after struct shash_desc with long long. No trailing padding is required because it is not a struct type that can be used in an array. The CRYPTO_MINALIGN_ATTR is required so that desc is aligned with long long as would be the case for a struct containing a member with CRYPTO_MINALIGN_ATTR. Signed-off-by: Jan-Simon Möller Signed-off-by: Behan Webster Signed-off-by: Vinícius Tinti Signed-off-by: Mark Charlebois --- fs/btrfs/hash.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c index 85889aa..a62743f 100644 --- a/fs/btrfs/hash.c +++ b/fs/btrfs/hash.c @@ -33,18 +33,18 @@ void btrfs_hash_exit(void) u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length) { - struct { - struct shash_desc shash; - char ctx[crypto_shash_descsize(tfm)]; - } desc; + char desc[sizeof(struct shash_desc) + + crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR; + struct shash_desc *shash = (struct shash_desc *)desc; + u32 *ctx = (u32 *)shash_desc_ctx(shash); int err; - desc.shash.tfm = tfm; - desc.shash.flags = 0; - *(u32 *)desc.ctx = crc; + shash->tfm = tfm; + shash->flags = 0; + *ctx = crc; - err = crypto_shash_update(&desc.shash, address, length); + err = crypto_shash_update(shash, address, length); BUG_ON(err); - return *(u32 *)desc.ctx; + return *ctx; } -- 1.9.1