Commit 877b5691 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

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: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 75f22228

Documentation/crypto/api-samples.rst

+0 −1
Original line number Diff line number Diff line
@@ -133,7 +133,6 @@ Code Example For Use of Operational State Memory With SHASH 
        if (!sdesc)

            return ERR_PTR(-ENOMEM);

        sdesc->shash.tfm = alg;

        sdesc->shash.flags = 0x0;

        return sdesc;

    }

arch/arm/crypto/ghash-ce-glue.c

+0 −3
Original line number Diff line number Diff line
@@ -186,7 +186,6 @@ static int ghash_async_init(struct ahash_request *req) 
	struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);



	desc->tfm = child;

	desc->flags = req->base.flags;

	return crypto_shash_init(desc);

}
@@ -243,7 +242,6 @@ static int ghash_async_digest(struct ahash_request *req) 
		struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);



		desc->tfm = child;

		desc->flags = req->base.flags;

		return shash_ahash_digest(req, desc);

	}

}
@@ -256,7 +254,6 @@ static int ghash_async_import(struct ahash_request *req, const void *in) 
	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);



	desc->tfm = cryptd_ahash_child(ctx->cryptd_tfm);

	desc->flags = req->base.flags;



	return crypto_shash_import(desc, in);

}

arch/x86/crypto/ghash-clmulni-intel_glue.c

+0 −2
Original line number Diff line number Diff line
@@ -172,7 +172,6 @@ static int ghash_async_init(struct ahash_request *req) 
	struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);



	desc->tfm = child;

	desc->flags = req->base.flags;

	return crypto_shash_init(desc);

}
@@ -252,7 +251,6 @@ static int ghash_async_digest(struct ahash_request *req) 
		struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);



		desc->tfm = child;

		desc->flags = req->base.flags;

		return shash_ahash_digest(req, desc);

	}

}

arch/x86/power/hibernate.c

+0 −1
Original line number Diff line number Diff line
@@ -90,7 +90,6 @@ static int get_e820_md5(struct e820_table *table, void *buf) 
	}



	desc->tfm = tfm;

	desc->flags = 0;



	size = offsetof(struct e820_table, entries) +

		sizeof(struct e820_entry) * table->nr_entries;

crypto/adiantum.c

+0 −1
Original line number Diff line number Diff line
@@ -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)

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