[PATCH] i386: pte xchg optimization

[powerpc.git] / include / asm-i386 / uaccess.h

diff --git a/include/asm-i386/uaccess.h b/include/asm-i386/uaccess.h
index 54d905e..e2aa5e0 100644 (file)
--- a/include/asm-i386/uaccess.h
+++ b/include/asm-i386/uaccess.h
@@ -54,10 +54,10 @@ extern struct movsl_mask {
  * This needs 33-bit arithmetic. We have a carry...
  */
 #define __range_ok(addr,size) ({ \
-       unsigned long flag,sum; \
+       unsigned long flag,roksum; \
        __chk_user_ptr(addr); \
        asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \
-               :"=&r" (flag), "=r" (sum) \
+               :"=&r" (flag), "=r" (roksum) \
                :"1" (addr),"g" ((int)(size)),"rm" (current_thread_info()->addr_limit.seg)); \
        flag; })
 
@@ -397,27 +397,25 @@ unsigned long __must_check __copy_from_user_ll_nocache(void *to,
 unsigned long __must_check __copy_from_user_ll_nocache_nozero(void *to,
                                const void __user *from, unsigned long n);
 
-/*
- * Here we special-case 1, 2 and 4-byte copy_*_user invocations.  On a fault
- * we return the initial request size (1, 2 or 4), as copy_*_user should do.
- * If a store crosses a page boundary and gets a fault, the x86 will not write
- * anything, so this is accurate.
- */
-
 /**
- * __copy_to_user: - Copy a block of data into user space, with less checking.
+ * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking.
  * @to:   Destination address, in user space.
  * @from: Source address, in kernel space.
  * @n:    Number of bytes to copy.
  *
- * Context: User context only.  This function may sleep.
+ * Context: User context only.
  *
  * Copy data from kernel space to user space.  Caller must check
  * the specified block with access_ok() before calling this function.
+ * The caller should also make sure he pins the user space address
+ * so that the we don't result in page fault and sleep.
  *
- * Returns number of bytes that could not be copied.
- * On success, this will be zero.
+ * Here we special-case 1, 2 and 4-byte copy_*_user invocations.  On a fault
+ * we return the initial request size (1, 2 or 4), as copy_*_user should do.
+ * If a store crosses a page boundary and gets a fault, the x86 will not write
+ * anything, so this is accurate.
  */
+
 static __always_inline unsigned long __must_check
 __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
 {
@@ -439,35 +437,27 @@ __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
        return __copy_to_user_ll(to, from, n);
 }
 
-static __always_inline unsigned long __must_check
-__copy_to_user(void __user *to, const void *from, unsigned long n)
-{
-       might_sleep();
-       return __copy_to_user_inatomic(to, from, n);
-}
-
 /**
- * __copy_from_user: - Copy a block of data from user space, with less checking.
- * @to:   Destination address, in kernel space.
- * @from: Source address, in user space.
+ * __copy_to_user: - Copy a block of data into user space, with less checking.
+ * @to:   Destination address, in user space.
+ * @from: Source address, in kernel space.
  * @n:    Number of bytes to copy.
  *
  * Context: User context only.  This function may sleep.
  *
- * Copy data from user space to kernel space.  Caller must check
+ * Copy data from kernel space to user space.  Caller must check
  * the specified block with access_ok() before calling this function.
  *
  * Returns number of bytes that could not be copied.
  * On success, this will be zero.
- *
- * If some data could not be copied, this function will pad the copied
- * data to the requested size using zero bytes.
- *
- * An alternate version - __copy_from_user_inatomic() - may be called from
- * atomic context and will fail rather than sleep.  In this case the
- * uncopied bytes will *NOT* be padded with zeros.  See fs/filemap.h
- * for explanation of why this is needed.
  */
+static __always_inline unsigned long __must_check
+__copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+       might_sleep();
+       return __copy_to_user_inatomic(to, from, n);
+}
+
 static __always_inline unsigned long
 __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
 {
@@ -493,6 +483,29 @@ __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
        }
        return __copy_from_user_ll_nozero(to, from, n);
 }
+
+/**
+ * __copy_from_user: - Copy a block of data from user space, with less checking.
+ * @to:   Destination address, in kernel space.
+ * @from: Source address, in user space.
+ * @n:    Number of bytes to copy.
+ *
+ * Context: User context only.  This function may sleep.
+ *
+ * Copy data from user space to kernel space.  Caller must check
+ * the specified block with access_ok() before calling this function.
+ *
+ * Returns number of bytes that could not be copied.
+ * On success, this will be zero.
+ *
+ * If some data could not be copied, this function will pad the copied
+ * data to the requested size using zero bytes.
+ *
+ * An alternate version - __copy_from_user_inatomic() - may be called from
+ * atomic context and will fail rather than sleep.  In this case the
+ * uncopied bytes will *NOT* be padded with zeros.  See fs/filemap.h
+ * for explanation of why this is needed.
+ */
 static __always_inline unsigned long
 __copy_from_user(void *to, const void __user *from, unsigned long n)
 {