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>

9 files changed, 0 insertions, 25 deletions

diff --git a/crypto/adiantum.c b/crypto/adiantum.c
index e6de50f669aa..395a3ddd3707 100644
--- a/crypto/adiantum.c
+++ b/crypto/adiantum.c
@@ -265,7 +265,6 @@ static int adiantum_hash_message(struct skcipher_request *req,
         int err;
 
         hash_desc->tfm = tctx->hash;
-        hash_desc->flags = 0;
 
         err = crypto_shash_init(hash_desc);
         if (err)
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index 97c77f66b20d..f7b0980bf02d 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -56,7 +56,6 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
                 goto error_no_desc;
 
         desc->tfm   = tfm;
-        desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
         /* Digest the message [RFC2315 9.3] */
         ret = crypto_shash_digest(desc, pkcs7->data, pkcs7->data_len,
diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c
index d178650fd524..f8e4a932bcfb 100644
--- a/crypto/asymmetric_keys/verify_pefile.c
+++ b/crypto/asymmetric_keys/verify_pefile.c
@@ -354,7 +354,6 @@ static int pefile_digest_pe(const void *pebuf, unsigned int pelen,
                 goto error_no_desc;
 
         desc->tfm   = tfm;
-        desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
         ret = crypto_shash_init(desc);
         if (ret < 0)
                 goto error;
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 9338b4558cdc..bd96683d8cde 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -77,7 +77,6 @@ int x509_get_sig_params(struct x509_certificate *cert)
                 goto error;
 
         desc->tfm = tfm;
-        desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
         ret = crypto_shash_digest(desc, cert->tbs, cert->tbs_size, sig->digest);
         if (ret < 0)
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);
 }
diff --git a/crypto/drbg.c b/crypto/drbg.c
index 710b3046a4df..2a5b16bb000c 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1587,7 +1587,6 @@ static int drbg_init_hash_kernel(struct drbg_state *drbg)
         }
 
         sdesc->shash.tfm = tfm;
-        sdesc->shash.flags = 0;
         drbg->priv_data = sdesc;
 
         return crypto_shash_alignmask(tfm);
diff --git a/crypto/hmac.c b/crypto/hmac.c
index 4ceb3f1f0eb8..a68c1266121f 100644
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -57,8 +57,6 @@ static int hmac_setkey(struct crypto_shash *parent,
         unsigned int i;
 
         shash->tfm = hash;
-        shash->flags = crypto_shash_get_flags(parent)
-                & CRYPTO_TFM_REQ_MAY_SLEEP;
 
         if (keylen > bs) {
                 int err;
@@ -91,8 +89,6 @@ static int hmac_export(struct shash_desc *pdesc, void *out)
 {
         struct shash_desc *desc = shash_desc_ctx(pdesc);
 
-        desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
-
         return crypto_shash_export(desc, out);
 }
 
@@ -102,7 +98,6 @@ static int hmac_import(struct shash_desc *pdesc, const void *in)
         struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
 
         desc->tfm = ctx->hash;
-        desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
 
         return crypto_shash_import(desc, in);
 }
@@ -117,8 +112,6 @@ static int hmac_update(struct shash_desc *pdesc,
 {
         struct shash_desc *desc = shash_desc_ctx(pdesc);
 
-        desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
-
         return crypto_shash_update(desc, data, nbytes);
 }
 
@@ -130,8 +123,6 @@ static int hmac_final(struct shash_desc *pdesc, u8 *out)
         char *opad = crypto_shash_ctx_aligned(parent) + ss;
         struct shash_desc *desc = shash_desc_ctx(pdesc);
 
-        desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
-
         return crypto_shash_final(desc, out) ?:
                crypto_shash_import(desc, opad) ?:
                crypto_shash_finup(desc, out, ds, out);
@@ -147,8 +138,6 @@ static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
         char *opad = crypto_shash_ctx_aligned(parent) + ss;
         struct shash_desc *desc = shash_desc_ctx(pdesc);
 
-        desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
-
         return crypto_shash_finup(desc, data, nbytes, out) ?:
                crypto_shash_import(desc, opad) ?:
                crypto_shash_finup(desc, out, ds, out);
diff --git a/crypto/shash.c b/crypto/shash.c
index 599468478f7b..e55c1f558bc3 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -238,7 +238,6 @@ static int shash_async_init(struct ahash_request *req)
         struct shash_desc *desc = ahash_request_ctx(req);
 
         desc->tfm = *ctx;
-        desc->flags = req->base.flags;
 
         return crypto_shash_init(desc);
 }
@@ -293,7 +292,6 @@ static int shash_async_finup(struct ahash_request *req)
         struct shash_desc *desc = ahash_request_ctx(req);
 
         desc->tfm = *ctx;
-        desc->flags = req->base.flags;
 
         return shash_ahash_finup(req, desc);
 }
@@ -328,7 +326,6 @@ static int shash_async_digest(struct ahash_request *req)
         struct shash_desc *desc = ahash_request_ctx(req);
 
         desc->tfm = *ctx;
-        desc->flags = req->base.flags;
 
         return shash_ahash_digest(req, desc);
 }
@@ -344,7 +341,6 @@ static int shash_async_import(struct ahash_request *req, const void *in)
         struct shash_desc *desc = ahash_request_ctx(req);
 
         desc->tfm = *ctx;
-        desc->flags = req->base.flags;
 
         return crypto_shash_import(desc, in);
 }
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 87abfd1ce232..2bd89a65e9e7 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1328,7 +1328,6 @@ static void generate_random_hash_testvec(struct crypto_shash *tfm,
 
         /* Digest */
         desc->tfm = tfm;
-        desc->flags = 0;
         vec->digest_error = crypto_shash_digest(desc, vec->plaintext,
                                                 vec->psize, (u8 *)vec->digest);
 done:
@@ -3027,7 +3026,6 @@ static int alg_test_crc32c(const struct alg_test_desc *desc,
                 u32 *ctx = (u32 *)shash_desc_ctx(shash);
 
                 shash->tfm = tfm;
-                shash->flags = 0;
 
                 *ctx = 420553207;
                 err = crypto_shash_final(shash, (u8 *)&val);