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Subject[PATCH v2 14/20] mips: csum_and_copy_{to,from}_user() are never called under KERNEL_DS
Date
From: Al Viro <viro@zeniv.linux.org.uk>

they are only called for iovec-backed iov_iter and under KERNEL_DS an
attempt to create such a beast will yield a kvec-backed one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/mips/include/asm/checksum.h | 32 +++++++-------------------------
1 file changed, 7 insertions(+), 25 deletions(-)

diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index b882cacea3ee..5cf4ce11c821 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -41,22 +41,6 @@ __wsum __csum_partial_copy_from_user(const void *src, void *dst,
int len, __wsum sum, int *err_ptr);
__wsum __csum_partial_copy_to_user(const void *src, void *dst,
int len, __wsum sum, int *err_ptr);
-/*
- * this is a new version of the above that records errors it finds in *errp,
- * but continues and zeros the rest of the buffer.
- */
-static inline
-__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
- __wsum sum, int *err_ptr)
-{
- might_fault();
- if (uaccess_kernel())
- return __csum_partial_copy_kernel((__force void *)src, dst,
- len, sum, err_ptr);
- else
- return __csum_partial_copy_from_user((__force void *)src, dst,
- len, sum, err_ptr);
-}

#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
static inline
@@ -65,9 +49,12 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
__wsum sum = ~0U;
int err = 0;

+ might_fault();
+
if (!access_ok(src, len))
return 0;
- sum = csum_partial_copy_from_user(src, dst, len, sum, &err);
+ sum = __csum_partial_copy_from_user((__force void *)src, dst,
+ len, sum, &err);
return err ? 0 : sum;
}

@@ -84,14 +71,9 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
might_fault();
if (!access_ok(dst, len))
return 0;
- if (uaccess_kernel())
- sum = __csum_partial_copy_kernel(src,
- (__force void *)dst,
- len, sum, &err);
- else
- sum = __csum_partial_copy_to_user(src,
- (__force void *)dst,
- len, sum, &err);
+ sum = __csum_partial_copy_to_user(src,
+ (__force void *)dst,
+ len, sum, &err);
return err ? 0 : sum;
}

--
2.11.0
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