Linux 3.14

[~andy/linux] / lib / strncpy_from_user.c

diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index c4c09b0e96bac19ad91cf6dae91d2785af901801..bb2b201d6ad0397a77df53d1841f148af4465170 100644 (file)
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -4,37 +4,7 @@
 #include <linux/errno.h>
 
 #include <asm/byteorder.h>
-
-static inline long find_zero(unsigned long mask)
-{
-       long byte = 0;
-
-#ifdef __BIG_ENDIAN
-#ifdef CONFIG_64BIT
-       if (mask >> 32)
-               mask >>= 32;
-       else
-               byte = 4;
-#endif
-       if (mask >> 16)
-               mask >>= 16;
-       else
-               byte += 2;
-       return (mask >> 8) ? byte : byte + 1;
-#else
-#ifdef CONFIG_64BIT
-       if (!((unsigned int) mask)) {
-               mask >>= 32;
-               byte = 4;
-       }
-#endif
-       if (!(mask & 0xffff)) {
-               mask >>= 16;
-               byte += 2;
-       }
-       return (mask & 0xff) ? byte : byte + 1;
-#endif
-}
+#include <asm/word-at-a-time.h>
 
 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 #define IS_UNALIGNED(src, dst) 0
@@ -51,8 +21,7 @@ static inline long find_zero(unsigned long mask)
  */
 static inline long do_strncpy_from_user(char *dst, const char __user *src, long count, unsigned long max)
 {
-       const unsigned long high_bits = REPEAT_BYTE(0xfe) + 1;
-       const unsigned long low_bits = REPEAT_BYTE(0x7f);
+       const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
        long res = 0;
 
        /*
@@ -66,18 +35,16 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long
                goto byte_at_a_time;
 
        while (max >= sizeof(unsigned long)) {
-               unsigned long c, v, rhs;
+               unsigned long c, data;
 
                /* Fall back to byte-at-a-time if we get a page fault */
                if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
                        break;
-               rhs = c | low_bits;
-               v = (c + high_bits) & ~rhs;
                *(unsigned long *)(dst+res) = c;
-               if (v) {
-                       v = (c & low_bits) + low_bits;
-                       v = ~(v | rhs);
-                       return res + find_zero(v);
+               if (has_zero(c, &data, &constants)) {
+                       data = prep_zero_mask(c, data, &constants);
+                       data = create_zero_mask(data);
+                       return res + find_zero(data);
                }
                res += sizeof(unsigned long);
                max -= sizeof(unsigned long);