powerpc: uaccess s/might_sleep/might_fault/

The only reason uaccess routines might sleep
is if they fault. Make this explicit.

Arnd Bergmann suggested that the following code
	if (!is_kernel_addr((unsigned long)__pu_addr))
		might_fault();
can be further simplified by adding a version of might_fault
that includes the kernel addr check.

Will be considered as a further optimization in future.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1369577426-26721-7-git-send-email-mst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 4db4959..9485b43 100644 (file)
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -178,7 +178,7 @@ do {                                                                \
        long __pu_err;                                          \
        __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
        if (!is_kernel_addr((unsigned long)__pu_addr))          \
-               might_sleep();                                  \
+               might_fault();                                  \
        __chk_user_ptr(ptr);                                    \
        __put_user_size((x), __pu_addr, (size), __pu_err);      \
        __pu_err;                                               \
@@ -188,7 +188,7 @@ do {                                                                \
 ({                                                                     \
        long __pu_err = -EFAULT;                                        \
        __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
-       might_sleep();                                                  \
+       might_fault();                                                  \
        if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
                __put_user_size((x), __pu_addr, (size), __pu_err);      \
        __pu_err;                                                       \
@@ -268,7 +268,7 @@ do {                                                                \
        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
        __chk_user_ptr(ptr);                                    \
        if (!is_kernel_addr((unsigned long)__gu_addr))          \
-               might_sleep();                                  \
+               might_fault();                                  \
        __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
        (x) = (__typeof__(*(ptr)))__gu_val;                     \
        __gu_err;                                               \
@@ -282,7 +282,7 @@ do {                                                                \
        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
        __chk_user_ptr(ptr);                                    \
        if (!is_kernel_addr((unsigned long)__gu_addr))          \
-               might_sleep();                                  \
+               might_fault();                                  \
        __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
        (x) = (__typeof__(*(ptr)))__gu_val;                     \
        __gu_err;                                               \
@@ -294,7 +294,7 @@ do {                                                                \
        long __gu_err = -EFAULT;                                        \
        unsigned long  __gu_val = 0;                                    \
        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
-       might_sleep();                                                  \
+       might_fault();                                                  \
        if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
                __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
        (x) = (__typeof__(*(ptr)))__gu_val;                             \
@@ -419,14 +419,14 @@ static inline unsigned long __copy_to_user_inatomic(void __user *to,
 static inline unsigned long __copy_from_user(void *to,
                const void __user *from, unsigned long size)
 {
-       might_sleep();
+       might_fault();
        return __copy_from_user_inatomic(to, from, size);
 }
 
 static inline unsigned long __copy_to_user(void __user *to,
                const void *from, unsigned long size)
 {
-       might_sleep();
+       might_fault();
        return __copy_to_user_inatomic(to, from, size);
 }
 
@@ -434,7 +434,7 @@ extern unsigned long __clear_user(void __user *addr, unsigned long size);
 
 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 {
-       might_sleep();
+       might_fault();
        if (likely(access_ok(VERIFY_WRITE, addr, size)))
                return __clear_user(addr, size);
        if ((unsigned long)addr < TASK_SIZE) {