From: Vinícius Tinti <viniciustinti@xxxxxxxxx>
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 <dl9pf@xxxxxx>
Signed-off-by: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Vinícius Tinti <viniciustinti@xxxxxxxxx>
Signed-off-by: Mark Charlebois <charlebm@xxxxxxxxx>
---
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..2fdacda 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
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