[PATCH] add likely around access_ok for uaccess

[Manfred Spraul <manfred@colorfullife.com>]

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Hi,

while trying to figure out why sysv msg is around 30% slower than pipes 
for data transfers I noticed that gcc's autodetection (3.2.2) guesses 
the "if(access_ok())" tests in uaccess.h wrong and puts the error memset 
into the direct path and the copy out of line.

The attached patch adds likely to the tests - any objections? What about 
the archs except i386?

--
    Manfred

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--- 2.6/include/asm-i386/uaccess.h	2003-09-12 21:53:58.000000000 +0200
+++ build-2.6/include/asm-i386/uaccess.h	2003-09-14 12:56:19.000000000 +0200
@@ -300,7 +300,7 @@
 	long __pu_err = -EFAULT;					\
 	__typeof__(*(ptr)) *__pu_addr = (ptr);				\
 	might_sleep();						\
-	if (access_ok(VERIFY_WRITE,__pu_addr,size))			\
+	if (likely(access_ok(VERIFY_WRITE,__pu_addr,size)))			\
 		__put_user_size((x),__pu_addr,(size),__pu_err,-EFAULT);	\
 	__pu_err;							\
 })							
@@ -510,7 +510,7 @@
 direct_copy_to_user(void __user *to, const void *from, unsigned long n)
 {
 	might_sleep();
-	if (access_ok(VERIFY_WRITE, to, n))
+	if (likely(access_ok(VERIFY_WRITE, to, n)))
 		n = __direct_copy_to_user(to, from, n);
 	return n;
 }
@@ -535,7 +535,7 @@
 direct_copy_from_user(void *to, const void __user *from, unsigned long n)
 {
 	might_sleep();
-	if (access_ok(VERIFY_READ, from, n))
+	if (likely(access_ok(VERIFY_READ, from, n)))
 		n = __direct_copy_from_user(to, from, n);
 	else
 		memset(to, 0, n);