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, 15 deletions

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index bee203055b30..1a6040998227 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -917,7 +917,6 @@ cifs_alloc_hash(const char *name,
 	}
 
 	(*sdesc)->shash.tfm = *shash;
-	(*sdesc)->shash.flags = 0x0;
 	return 0;
 }
 
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 322ce9686bdb..2cb4956f8511 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -402,7 +402,6 @@ static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
 	{
 		SHASH_DESC_ON_STACK(desc, tfm);
 		desc->tfm = tfm;
-		desc->flags = 0;
 
 		return crypto_shash_digest(desc, key, keysize, salt);
 	}
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index f664da55234e..491cf5baa8c2 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -68,7 +68,6 @@ static int ecryptfs_hash_digest(struct crypto_shash *tfm,
 	int err;
 
 	desc->tfm = tfm;
-	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 	err = crypto_shash_digest(desc, src, len, dst);
 	shash_desc_zero(desc);
 	return err;
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index e74fe84d0886..90fbac5d485b 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -769,7 +769,6 @@ ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
 	}
 
 	s->hash_desc->tfm = s->hash_tfm;
-	s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	rc = crypto_shash_digest(s->hash_desc,
 				 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 82ffdacdc7fa..0833b5fc0668 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2024,7 +2024,6 @@ static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc,
 	BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver)!=sizeof(desc.ctx));
 
 	desc.shash.tfm = sbi->s_chksum_driver;
-	desc.shash.flags = 0;
 	*(u32 *)desc.ctx = crc;
 
 	BUG_ON(crypto_shash_update(&desc.shash, address, length));
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 87f75ebd2fd6..21b0ab6bd15a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1422,7 +1422,6 @@ static inline u32 __f2fs_crc32(struct f2fs_sb_info *sbi, u32 crc,
 	BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver) != sizeof(desc.ctx));
 
 	desc.shash.tfm = sbi->s_chksum_driver;
-	desc.shash.flags = 0;
 	*(u32 *)desc.ctx = crc;
 
 	err = crypto_shash_update(&desc.shash, address, length);
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 5188f9f70c78..8c8563441208 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -126,7 +126,6 @@ nfs4_make_rec_clidname(char *dname, const struct xdr_netobj *clname)
 		SHASH_DESC_ON_STACK(desc, tfm);
 
 		desc->tfm = tfm;
-		desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 		status = crypto_shash_digest(desc, clname->data, clname->len,
 					     cksum.data);
diff --git a/fs/ubifs/auth.c b/fs/ubifs/auth.c
index 5bf5fd08879e..b758004085c4 100644
--- a/fs/ubifs/auth.c
+++ b/fs/ubifs/auth.c
@@ -33,7 +33,6 @@ int __ubifs_node_calc_hash(const struct ubifs_info *c, const void *node,
 	int err;
 
 	shash->tfm = c->hash_tfm;
-	shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	err = crypto_shash_digest(shash, node, le32_to_cpu(ch->len), hash);
 	if (err < 0)
@@ -56,7 +55,6 @@ static int ubifs_hash_calc_hmac(const struct ubifs_info *c, const u8 *hash,
 	int err;
 
 	shash->tfm = c->hmac_tfm;
-	shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	err = crypto_shash_digest(shash, hash, c->hash_len, hmac);
 	if (err < 0)
@@ -88,7 +86,6 @@ int ubifs_prepare_auth_node(struct ubifs_info *c, void *node,
 		return -ENOMEM;
 
 	hash_desc->tfm = c->hash_tfm;
-	hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 	ubifs_shash_copy_state(c, inhash, hash_desc);
 
 	err = crypto_shash_final(hash_desc, hash);
@@ -123,7 +120,6 @@ static struct shash_desc *ubifs_get_desc(const struct ubifs_info *c,
 		return ERR_PTR(-ENOMEM);
 
 	desc->tfm = tfm;
-	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	err = crypto_shash_init(desc);
 	if (err) {
@@ -364,7 +360,6 @@ static int ubifs_node_calc_hmac(const struct ubifs_info *c, const void *node,
 	ubifs_assert(c, ofs_hmac + hmac_len < len);
 
 	shash->tfm = c->hmac_tfm;
-	shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	err = crypto_shash_init(shash);
 	if (err)
@@ -483,7 +478,6 @@ int ubifs_hmac_wkm(struct ubifs_info *c, u8 *hmac)
 		return 0;
 
 	shash->tfm = c->hmac_tfm;
-	shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	err = crypto_shash_init(shash);
 	if (err)
diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c
index 0a0e65c07c6d..5c8a81a019a4 100644
--- a/fs/ubifs/replay.c
+++ b/fs/ubifs/replay.c
@@ -576,7 +576,6 @@ static int authenticate_sleb_hash(struct ubifs_info *c, struct shash_desc *log_h
 	SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm);
 
 	hash_desc->tfm = c->hash_tfm;
-	hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	ubifs_shash_copy_state(c, log_hash, hash_desc);
 	return crypto_shash_final(hash_desc, hash);
@@ -587,7 +586,6 @@ static int authenticate_sleb_hmac(struct ubifs_info *c, u8 *hash, u8 *hmac)
 	SHASH_DESC_ON_STACK(hmac_desc, c->hmac_tfm);
 
 	hmac_desc->tfm = c->hmac_tfm;
-	hmac_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	return crypto_shash_digest(hmac_desc, hash, c->hash_len, hmac);
 }