From 877b5691f27a1aec0d9b53095a323e45c30069e2 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 14 Apr 2019 17:37:09 -0700 Subject: 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 Signed-off-by: Herbert Xu --- drivers/thunderbolt/domain.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/thunderbolt') diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c index 7416bdbd8576..b7980c856898 100644 --- a/drivers/thunderbolt/domain.c +++ b/drivers/thunderbolt/domain.c @@ -678,7 +678,6 @@ int tb_domain_challenge_switch_key(struct tb *tb, struct tb_switch *sw) } shash->tfm = tfm; - shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP; memset(hmac, 0, sizeof(hmac)); ret = crypto_shash_digest(shash, challenge, sizeof(hmac), hmac); -- cgit v1.2.3