Re: [PATCHv4 6/8] crypto: add rocksoft 64b crc guard tag framework

[Keith Busch <kbusch@kernel.org>]

On Wed, Mar 09, 2022 at 07:49:07PM +0000, Eric Biggers wrote:
> The issue is that every other "shash" algorithm besides crct10dif, including
> crc32 and crc32c, follow the convention of treating the digest as bytes.  Doing
> otherwise is unusual for the crypto API.  So I have a slight preference for
> treating it as bytes.  Perhaps see what Herbert Xu (maintainer of the crypto
> API, Cc'ed) recommends?

I'm okay either way, they're both simple enough. Here is an update atop
this series to match the other shash conventions if this is preferred
over my previous fix:

---
diff --git a/block/t10-pi.c b/block/t10-pi.c
index 914d8cddd43a..f9eb45571bc7 100644
--- a/block/t10-pi.c
+++ b/block/t10-pi.c
@@ -282,7 +282,7 @@ EXPORT_SYMBOL(t10_pi_type3_ip);
 
 static __be64 ext_pi_crc64(void *data, unsigned int len)
 {
-	return cpu_to_be64(crc64_rocksoft(data, len));
+	return cpu_to_be64(le64_to_cpu(crc64_rocksoft(data, len)));
 }
 
 static blk_status_t ext_pi_crc64_generate(struct blk_integrity_iter *iter,
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index f1a22794c404..f9e5f601c657 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -3686,11 +3686,11 @@ static const struct hash_testvec crc64_rocksoft_tv_template[] = {
 	{
 		.plaintext	= zeroes,
 		.psize		= 4096,
-		.digest		= (u8 *)(u64[]){ 0x6482d367eb22b64eull },
+		.digest		= "\x4e\xb6\x22\xeb\x67\xd3\x82\x64",
 	}, {
 		.plaintext	= ones,
 		.psize		= 4096,
-		.digest		= (u8 *)(u64[]){ 0xc0ddba7302eca3acull },
+		.digest		= "\xac\xa3\xec\x02\x73\xba\xdd\xc0",
 	}
 };
 
diff --git a/include/linux/crc64.h b/include/linux/crc64.h
index e044c60d1e61..5319f9a9fc19 100644
--- a/include/linux/crc64.h
+++ b/include/linux/crc64.h
@@ -12,7 +12,7 @@
 u64 __pure crc64_be(u64 crc, const void *p, size_t len);
 u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len);
 
-u64 crc64_rocksoft(const unsigned char *buffer, size_t len);
-u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len);
+__le64 crc64_rocksoft(const unsigned char *buffer, size_t len);
+__le64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len);
 
 #endif /* _LINUX_CRC64_H */
diff --git a/lib/crc64-rocksoft.c b/lib/crc64-rocksoft.c
index fc9ae0da5df7..215acb79a15d 100644
--- a/lib/crc64-rocksoft.c
+++ b/lib/crc64-rocksoft.c
@@ -54,16 +54,16 @@ static struct notifier_block crc64_rocksoft_nb = {
 	.notifier_call = crc64_rocksoft_notify,
 };
 
-u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len)
+__le64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len)
 {
 	struct {
 		struct shash_desc shash;
-		u64 crc;
+		__le64 crc;
 	} desc;
 	int err;
 
 	if (static_branch_unlikely(&crc64_rocksoft_fallback))
-		return crc64_rocksoft_generic(crc, buffer, len);
+		return cpu_to_le64(crc64_rocksoft_generic(crc, buffer, len));
 
 	rcu_read_lock();
 	desc.shash.tfm = rcu_dereference(crc64_rocksoft_tfm);
@@ -77,7 +77,7 @@ u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len)
 }
 EXPORT_SYMBOL_GPL(crc64_rocksoft_update);
 
-u64 crc64_rocksoft(const unsigned char *buffer, size_t len)
+__le64 crc64_rocksoft(const unsigned char *buffer, size_t len)
 {
 	return crc64_rocksoft_update(0, buffer, len);
 }
--