btrfs: LLVMLinux: Remove VLAIS

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: Vinícius Tinti <viniciustinti@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Acked-by: Chris Mason <clm@fb.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
(cherry picked from commit 0458a953d85088a9ba3e448745676377775879e0)

diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
index 85889aa82c62dd8d05d9c8a01cff08f86afc4d05..4bf4d3a3e5c46b41b92d1738f991f11f8e78d387 100644 (file)
--- 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;
 }