UPSTREAM: PCI: rockchip: Mark RC as common clock architecture

[firefly-linux-kernel-4.4.55.git] / lib / strnlen_user.c

diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
index 11649615c50504cb5976d58c8bf012d563bf2bbc..8e105ed4df12bb6bb0a170afff54d979c15d73c0 100644 (file)
--- a/lib/strnlen_user.c
+++ b/lib/strnlen_user.c
@@ -45,8 +45,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
        src -= align;
        max += align;
 
-       if (unlikely(__get_user(c,(unsigned long __user *)src)))
-               return 0;
+       unsafe_get_user(c, (unsigned long __user *)src, efault);
        c |= aligned_byte_mask(align);
 
        for (;;) {
@@ -61,8 +60,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
                if (unlikely(max <= sizeof(unsigned long)))
                        break;
                max -= sizeof(unsigned long);
-               if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
-                       return 0;
+               unsafe_get_user(c, (unsigned long __user *)(src+res), efault);
        }
        res -= align;
 
@@ -77,6 +75,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
         * Nope: we hit the address space limit, and we still had more
         * characters the caller would have wanted. That's 0.
         */
+efault:
        return 0;
 }
 
@@ -85,13 +84,21 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
  * @str: The string to measure.
  * @count: Maximum count (including NUL character)
  *
- * Context: User context only.  This function may sleep.
+ * Context: User context only. This function may sleep if pagefaults are
+ *          enabled.
  *
  * Get the size of a NUL-terminated string in user space.
  *
  * Returns the size of the string INCLUDING the terminating NUL.
- * If the string is too long, returns 'count+1'.
+ * If the string is too long, returns a number larger than @count. User
+ * has to check the return value against "> count".
  * On exception (or invalid count), returns 0.
+ *
+ * NOTE! You should basically never use this function. There is
+ * almost never any valid case for using the length of a user space
+ * string, since the string can be changed at any time by other
+ * threads. Use "strncpy_from_user()" instead to get a stable copy
+ * of the string.
  */
 long strnlen_user(const char __user *str, long count)
 {
@@ -104,7 +111,12 @@ long strnlen_user(const char __user *str, long count)
        src_addr = (unsigned long)str;
        if (likely(src_addr < max_addr)) {
                unsigned long max = max_addr - src_addr;
-               return do_strnlen_user(str, count, max);
+               long retval;
+
+               user_access_begin();
+               retval = do_strnlen_user(str, count, max);
+               user_access_end();
+               return retval;
        }
        return 0;
 }
@@ -114,7 +126,8 @@ EXPORT_SYMBOL(strnlen_user);
  * strlen_user: - Get the size of a user string INCLUDING final NUL.
  * @str: The string to measure.
  *
- * Context: User context only.  This function may sleep.
+ * Context: User context only. This function may sleep if pagefaults are
+ *          enabled.
  *
  * Get the size of a NUL-terminated string in user space.
  *
@@ -132,7 +145,12 @@ long strlen_user(const char __user *str)
        src_addr = (unsigned long)str;
        if (likely(src_addr < max_addr)) {
                unsigned long max = max_addr - src_addr;
-               return do_strnlen_user(str, ~0ul, max);
+               long retval;
+
+               user_access_begin();
+               retval = do_strnlen_user(str, ~0ul, max);
+               user_access_end();
+               return retval;
        }
        return 0;
 }