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authorEric Biggers <ebiggers@google.com>2019-04-15 03:37:09 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2019-04-25 10:38:12 +0300
commit877b5691f27a1aec0d9b53095a323e45c30069e2 (patch)
tree59eba93e8d253fb0e12a0a2040de99e96e873933 /crypto/cryptd.c
parent75f2222832e0fecba7a45ca6ac07ea895ea1e046 (diff)
downloadlinux-877b5691f27a1aec0d9b53095a323e45c30069e2.tar.xz
crypto: shash - remove shash_desc::flags
The flags field in 'struct shash_desc' never actually does anything. The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP. However, no shash algorithm ever sleeps, making this flag a no-op. With this being the case, inevitably some users who can't sleep wrongly pass MAY_SLEEP. These would all need to be fixed if any shash algorithm actually started sleeping. For example, the shash_ahash_*() functions, which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP from the ahash API to the shash API. However, the shash functions are called under kmap_atomic(), so actually they're assumed to never sleep. Even if it turns out that some users do need preemption points while hashing large buffers, we could easily provide a helper function crypto_shash_update_large() which divides the data into smaller chunks and calls crypto_shash_update() and cond_resched() for each chunk. It's not necessary to have a flag in 'struct shash_desc', nor is it necessary to make individual shash algorithms aware of this at all. Therefore, remove shash_desc::flags, and document that the crypto_shash_*() functions can be called from any context. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/cryptd.c')
-rw-r--r--crypto/cryptd.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index 42533cf80acc..b3bb99390ae7 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -545,7 +545,6 @@ static void cryptd_hash_init(struct crypto_async_request *req_async, int err)
goto out;
desc->tfm = child;
- desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
err = crypto_shash_init(desc);
@@ -637,7 +636,6 @@ static void cryptd_hash_digest(struct crypto_async_request *req_async, int err)
goto out;
desc->tfm = child;
- desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
err = shash_ahash_digest(req, desc);
@@ -666,7 +664,6 @@ static int cryptd_hash_import(struct ahash_request *req, const void *in)
struct shash_desc *desc = cryptd_shash_desc(req);
desc->tfm = ctx->child;
- desc->flags = req->base.flags;
return crypto_shash_import(desc, in);
}