linux-kernel - [RFC][PATCH 10/14] xtensa: switch to providing csum_and_copy_from

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Date:   Fri, 27 Mar 2020 23:31:13 +0000
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC][PATCH 10/14] xtensa: switch to providing csum_and_copy_from_user()

From: Al Viro <viro@...iv.linux.org.uk>

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 arch/xtensa/include/asm/checksum.h | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/xtensa/include/asm/checksum.h b/arch/xtensa/include/asm/checksum.h
index 8b687176ad72..d8292cc9ebdf 100644
--- a/arch/xtensa/include/asm/checksum.h
+++ b/arch/xtensa/include/asm/checksum.h
@@ -44,8 +44,6 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 /*
  *	Note: when you get a NULL pointer exception here this means someone
  *	passed in an incorrect kernel address to one of these functions.
- *
- *	If you use these functions directly please don't forget the access_ok().
  */
 static inline
 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
@@ -54,12 +52,17 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
 }
 
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
-__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
+__wsum csum_and_copy_from_user(const void __user *src, void *dst,
 				   int len, __wsum sum, int *err_ptr)
 {
-	return csum_partial_copy_generic((__force const void *)src, dst,
+	if (access_ok(dst, len))
+		return csum_partial_copy_generic((__force const void *)src, dst,
 					len, sum, err_ptr, NULL);
+	if (len)
+		*err_ptr = -EFAULT;
+	return sum;
 }
 
 /*
-- 
2.11.0