amd64: switch csum_partial_copy_generic() to new calling conventions

... and fold handling of misaligned case into it.

Implementation note: we stash the "will we need to rol8 the sum in the end"
flag into the MSB of %rcx (the lower 32 bits are used for length); the rest
is pretty straightforward.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 9 insertions, 63 deletions

diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index ae2fb87e2274..189344924a2b 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -21,49 +21,16 @@
  * src and dst are best aligned to 64bits.
  */
 __wsum
-csum_and_copy_from_user(const void __user *src, void *dst,
-			    int len)
+csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	int err = 0;
-	__wsum isum = ~0U;
+	__wsum sum;
 
 	might_sleep();
-
 	if (!user_access_begin(src, len))
 		return 0;
-
-	/*
-	 * Why 6, not 7? To handle odd addresses aligned we
-	 * would need to do considerable complications to fix the
-	 * checksum which is defined as an 16bit accumulator. The
-	 * fix alignment code is primarily for performance
-	 * compatibility with 32bit and that will handle odd
-	 * addresses slowly too.
-	 */
-	if (unlikely((unsigned long)src & 6)) {
-		while (((unsigned long)src & 6) && len >= 2) {
-			__u16 val16;
-
-			unsafe_get_user(val16, (const __u16 __user *)src, out);
-
-			*(__u16 *)dst = val16;
-			isum = (__force __wsum)add32_with_carry(
-					(__force unsigned)isum, val16);
-			src += 2;
-			dst += 2;
-			len -= 2;
-		}
-	}
-	isum = csum_partial_copy_generic((__force const void *)src,
-				dst, len, isum, &err, NULL);
-	user_access_end();
-	if (unlikely(err))
-		isum = 0;
-	return isum;
-
-out:
+	sum = csum_partial_copy_generic((__force const void *)src, dst, len);
 	user_access_end();
-	return 0;
+	return sum;
 }
 EXPORT_SYMBOL(csum_and_copy_from_user);
 
@@ -79,37 +46,16 @@ EXPORT_SYMBOL(csum_and_copy_from_user);
  * src and dst are best aligned to 64bits.
  */
 __wsum
-csum_and_copy_to_user(const void *src, void __user *dst,
-			  int len)
+csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
-	__wsum ret, isum = ~0U;
-	int err = 0;
+	__wsum sum;
 
 	might_sleep();
-
 	if (!user_access_begin(dst, len))
 		return 0;
-
-	if (unlikely((unsigned long)dst & 6)) {
-		while (((unsigned long)dst & 6) && len >= 2) {
-			__u16 val16 = *(__u16 *)src;
-
-			isum = (__force __wsum)add32_with_carry(
-					(__force unsigned)isum, val16);
-			unsafe_put_user(val16, (__u16 __user *)dst, out);
-			src += 2;
-			dst += 2;
-			len -= 2;
-		}
-	}
-
-	ret = csum_partial_copy_generic(src, (void __force *)dst,
-					len, isum, NULL, &err);
-	user_access_end();
-	return err ? 0 : ret;
-out:
+	sum = csum_partial_copy_generic(src, (void __force *)dst, len);
 	user_access_end();
-	return 0;
+	return sum;
 }
 EXPORT_SYMBOL(csum_and_copy_to_user);
 
@@ -125,7 +71,7 @@ EXPORT_SYMBOL(csum_and_copy_to_user);
 __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len);
 }
 EXPORT_SYMBOL(csum_partial_copy_nocheck);