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From:   Eric Biggers <ebiggers@kernel.org>
To:     linux-crypto@vger.kernel.org
Cc:     Nikolay Borisov <nborisov@suse.com>
Subject: [PATCH] lib/xxhash: make xxh{32,64}_update() return void
Date:   Fri,  1 May 2020 23:34:23 -0700
Message-Id: <20200502063423.1052614-1-ebiggers@kernel.org>
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From: Eric Biggers <ebiggers@google.com>

The return value of xxh64_update() is pointless and confusing, since an
error is only returned for input==NULL.  But the callers must ignore
this error because they might pass input=NULL, length=0.

Likewise for xxh32_update().

Just make these functions return void.

Cc: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---

lib/xxhash.c doesn't actually have a maintainer, but probably it makes
sense to take this through the crypto tree, alongside the other patch I
sent to return void in lib/crypto/sha256.c.

 include/linux/xxhash.h |  8 ++------
 lib/xxhash.c           | 20 ++++++--------------
 2 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/include/linux/xxhash.h b/include/linux/xxhash.h
index 52b073fea17fe4..e1c469802ebdba 100644
--- a/include/linux/xxhash.h
+++ b/include/linux/xxhash.h
@@ -185,10 +185,8 @@ void xxh32_reset(struct xxh32_state *state, uint32_t seed);
  * @length: The length of the data to hash.
  *
  * After calling xxh32_reset() call xxh32_update() as many times as necessary.
- *
- * Return:  Zero on success, otherwise an error code.
  */
-int xxh32_update(struct xxh32_state *state, const void *input, size_t length);
+void xxh32_update(struct xxh32_state *state, const void *input, size_t length);
 
 /**
  * xxh32_digest() - produce the current xxh32 hash
@@ -218,10 +216,8 @@ void xxh64_reset(struct xxh64_state *state, uint64_t seed);
  * @length: The length of the data to hash.
  *
  * After calling xxh64_reset() call xxh64_update() as many times as necessary.
- *
- * Return:  Zero on success, otherwise an error code.
  */
-int xxh64_update(struct xxh64_state *state, const void *input, size_t length);
+void xxh64_update(struct xxh64_state *state, const void *input, size_t length);
 
 /**
  * xxh64_digest() - produce the current xxh64 hash
diff --git a/lib/xxhash.c b/lib/xxhash.c
index aa61e2a3802f0a..64bb68a9621ed1 100644
--- a/lib/xxhash.c
+++ b/lib/xxhash.c
@@ -267,21 +267,19 @@ void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
 }
 EXPORT_SYMBOL(xxh64_reset);
 
-int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)
+void xxh32_update(struct xxh32_state *state, const void *input,
+		  const size_t len)
 {
 	const uint8_t *p = (const uint8_t *)input;
 	const uint8_t *const b_end = p + len;
 
-	if (input == NULL)
-		return -EINVAL;
-
 	state->total_len_32 += (uint32_t)len;
 	state->large_len |= (len >= 16) | (state->total_len_32 >= 16);
 
 	if (state->memsize + len < 16) { /* fill in tmp buffer */
 		memcpy((uint8_t *)(state->mem32) + state->memsize, input, len);
 		state->memsize += (uint32_t)len;
-		return 0;
+		return;
 	}
 
 	if (state->memsize) { /* some data left from previous update */
@@ -331,8 +329,6 @@ int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)
 		memcpy(state->mem32, p, (size_t)(b_end-p));
 		state->memsize = (uint32_t)(b_end-p);
 	}
-
-	return 0;
 }
 EXPORT_SYMBOL(xxh32_update);
 
@@ -374,20 +370,18 @@ uint32_t xxh32_digest(const struct xxh32_state *state)
 }
 EXPORT_SYMBOL(xxh32_digest);
 
-int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)
+void xxh64_update(struct xxh64_state *state, const void *input,
+		  const size_t len)
 {
 	const uint8_t *p = (const uint8_t *)input;
 	const uint8_t *const b_end = p + len;
 
-	if (input == NULL)
-		return -EINVAL;
-
 	state->total_len += len;
 
 	if (state->memsize + len < 32) { /* fill in tmp buffer */
 		memcpy(((uint8_t *)state->mem64) + state->memsize, input, len);
 		state->memsize += (uint32_t)len;
-		return 0;
+		return;
 	}
 
 	if (state->memsize) { /* tmp buffer is full */
@@ -436,8 +430,6 @@ int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)
 		memcpy(state->mem64, p, (size_t)(b_end-p));
 		state->memsize = (uint32_t)(b_end - p);
 	}
-
-	return 0;
 }
 EXPORT_SYMBOL(xxh64_update);
 
-- 
2.26.2