[PATCH v4 02/12] btrfs: LLVMLinux: Remove VLAIS

From: behanw
Date: Tue Sep 23 2014 - 00:46:56 EST


From: VinÃcius Tinti <viniciustinti@xxxxxxxxx>

Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
compliant equivalent. This patch instead allocates the appropriate amount of
memory using a char array using the SHASH_DESC_ON_STACK macro.

The new code can be compiled with both gcc and clang.

Signed-off-by: VinÃcius Tinti <viniciustinti@xxxxxxxxx>
Reviewed-by: Jan-Simon MÃller <dl9pf@xxxxxx>
Reviewed-by: Mark Charlebois <charlebm@xxxxxxxxx>
Signed-off-by: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx>
Acked-by: Chris Mason <clm@xxxxxx>
Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
---
fs/btrfs/hash.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
index 85889aa..4bf4d3a 100644
--- a/fs/btrfs/hash.c
+++ b/fs/btrfs/hash.c
@@ -33,18 +33,16 @@ 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;
+ SHASH_DESC_ON_STACK(shash, tfm);
+ 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

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