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Subject[PATCH 08/18] m68k: get rid of zeroing destination on error in csum_and_copy_from_user()
Date
From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/m68k/lib/checksum.c | 79 +++++++++---------------------------------------
1 file changed, 15 insertions(+), 64 deletions(-)

diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c
index 3aeca261f622..7e6afeae6217 100644
--- a/arch/m68k/lib/checksum.c
+++ b/arch/m68k/lib/checksum.c
@@ -236,82 +236,33 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len)
"clrl %5\n\t"
"addxl %5,%0\n\t" /* add X bit */
"7:\t"
- "clrl %5\n" /* no error - clear return value */
- "8:\n"
".section .fixup,\"ax\"\n"
".even\n"
- /* If any exception occurs zero out the rest.
- Similarities with the code above are intentional :-) */
+ /* If any exception occurs, return 0 */
"90:\t"
- "clrw %3@+\n\t"
- "movel %1,%4\n\t"
- "lsrl #5,%1\n\t"
- "jeq 1f\n\t"
- "subql #1,%1\n"
- "91:\t"
- "clrl %3@+\n"
- "92:\t"
- "clrl %3@+\n"
- "93:\t"
- "clrl %3@+\n"
- "94:\t"
- "clrl %3@+\n"
- "95:\t"
- "clrl %3@+\n"
- "96:\t"
- "clrl %3@+\n"
- "97:\t"
- "clrl %3@+\n"
- "98:\t"
- "clrl %3@+\n\t"
- "dbra %1,91b\n\t"
- "clrw %1\n\t"
- "subql #1,%1\n\t"
- "jcc 91b\n"
- "1:\t"
- "movel %4,%1\n\t"
- "andw #0x1c,%4\n\t"
- "jeq 1f\n\t"
- "lsrw #2,%4\n\t"
- "subqw #1,%4\n"
- "99:\t"
- "clrl %3@+\n\t"
- "dbra %4,99b\n\t"
- "1:\t"
- "andw #3,%1\n\t"
- "jeq 9f\n"
- "100:\t"
- "clrw %3@+\n\t"
- "tstw %1\n\t"
- "jeq 9f\n"
- "101:\t"
- "clrb %3@+\n"
- "9:\t"
-#define STR(X) STR1(X)
-#define STR1(X) #X
- "moveq #-" STR(EFAULT) ",%5\n\t"
- "jra 8b\n"
+ "clrl %0\n"
+ "jra 7b\n"
".previous\n"
".section __ex_table,\"a\"\n"
".long 10b,90b\n"
- ".long 11b,91b\n"
- ".long 12b,92b\n"
- ".long 13b,93b\n"
- ".long 14b,94b\n"
- ".long 15b,95b\n"
- ".long 16b,96b\n"
- ".long 17b,97b\n"
- ".long 18b,98b\n"
- ".long 19b,99b\n"
- ".long 20b,100b\n"
- ".long 21b,101b\n"
+ ".long 11b,90b\n"
+ ".long 12b,90b\n"
+ ".long 13b,90b\n"
+ ".long 14b,90b\n"
+ ".long 15b,90b\n"
+ ".long 16b,90b\n"
+ ".long 17b,90b\n"
+ ".long 18b,90b\n"
+ ".long 19b,90b\n"
+ ".long 20b,90b\n"
+ ".long 21b,90b\n"
".previous"
: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
"=&d" (tmp1), "=d" (tmp2)
: "0" (sum), "1" (len), "2" (src), "3" (dst)
);

- return tmp2 ? 0 : sum;
+ return sum;
}

EXPORT_SYMBOL(csum_and_copy_from_user);
--
2.11.0
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