crypto: mips/crc32 - Clean up useless assignment operations

When entering the "len & sizeof(u32)" branch, len must be less than 8.
So after one operation, len must be less than 4.
At this time, "len -= sizeof(u32)" is not necessary for 64-bit CPUs.

After that, replace `while' loops with equivalent `for' to make the
code structure a little bit better by the way.

Suggested-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/all/alpine.DEB.2.21.2406281713040.43454@angie.orcam.me.uk/
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://lore.kernel.org/all/ZtqZpzMH_qMQqzyc@gondor.apana.org.au/
Signed-off-by: Guan Wentao <guanwentao@uniontech.com>
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/mips/crypto/crc32-mips.c b/arch/mips/crypto/crc32-mips.c
index ec6d58008f8e10ad3df8256404f1ba17dc8cc9d9..2a59b85f88aacea20d11e6e8ddcb2b6c8006ebe4 100644 (file)
--- a/arch/mips/crypto/crc32-mips.c
+++ b/arch/mips/crypto/crc32-mips.c
@@ -77,24 +77,26 @@ static u32 crc32_mips_le_hw(u32 crc_, const u8 *p, unsigned int len)
 {
        u32 crc = crc_;
 
-#ifdef CONFIG_64BIT
-       while (len >= sizeof(u64)) {
-               u64 value = get_unaligned_le64(p);
-
-               CRC32(crc, value, d);
-               p += sizeof(u64);
-               len -= sizeof(u64);
-       }
-
-       if (len & sizeof(u32)) {
-#else /* !CONFIG_64BIT */
-       while (len >= sizeof(u32)) {
-#endif
-               u32 value = get_unaligned_le32(p);
-
-               CRC32(crc, value, w);
-               p += sizeof(u32);
-               len -= sizeof(u32);
+       if (IS_ENABLED(CONFIG_64BIT)) {
+               for (; len >= sizeof(u64); p += sizeof(u64), len -= sizeof(u64)) {
+                       u64 value = get_unaligned_le64(p);
+
+                       CRC32(crc, value, d);
+               }
+
+               if (len & sizeof(u32)) {
+                       u32 value = get_unaligned_le32(p);
+
+                       CRC32(crc, value, w);
+                       p += sizeof(u32);
+               }
+       } else {
+               for (; len >= sizeof(u32); len -= sizeof(u32)) {
+                       u32 value = get_unaligned_le32(p);
+
+                       CRC32(crc, value, w);
+                       p += sizeof(u32);
+               }
        }
 
        if (len & sizeof(u16)) {
@@ -117,24 +119,26 @@ static u32 crc32c_mips_le_hw(u32 crc_, const u8 *p, unsigned int len)
 {
        u32 crc = crc_;
 
-#ifdef CONFIG_64BIT
-       while (len >= sizeof(u64)) {
-               u64 value = get_unaligned_le64(p);
+       if (IS_ENABLED(CONFIG_64BIT)) {
+               for (; len >= sizeof(u64); p += sizeof(u64), len -= sizeof(u64)) {
+                       u64 value = get_unaligned_le64(p);
 
-               CRC32C(crc, value, d);
-               p += sizeof(u64);
-               len -= sizeof(u64);
-       }
+                       CRC32(crc, value, d);
+               }
 
-       if (len & sizeof(u32)) {
-#else /* !CONFIG_64BIT */
-       while (len >= sizeof(u32)) {
-#endif
-               u32 value = get_unaligned_le32(p);
+               if (len & sizeof(u32)) {
+                       u32 value = get_unaligned_le32(p);
+
+                       CRC32(crc, value, w);
+                       p += sizeof(u32);
+               }
+       } else {
+               for (; len >= sizeof(u32); len -= sizeof(u32)) {
+                       u32 value = get_unaligned_le32(p);
 
-               CRC32C(crc, value, w);
-               p += sizeof(u32);
-               len -= sizeof(u32);
+                       CRC32(crc, value, w);
+                       p += sizeof(u32);
+               }
        }
 
        if (len & sizeof(u16)) {