From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Tue, 8 Oct 2019 17:02:32 +0200
Subject: s390/uaccess: avoid (false positive) compiler warnings
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: 062795fcdcb2d22822fb42644b1d76a8ad8439b3
Patch-mainline: v5.4-rc3
References: git-fixes bsc#1215041

Depending on inlining decisions by the compiler, __get/put_user_fn
might become out of line. Then the compiler is no longer able to tell
that size can only be 1,2,4 or 8 due to the check in __get/put_user
resulting in false positives like

./arch/s390/include/asm/uaccess.h: In function ‘__put_user_fn’:
./arch/s390/include/asm/uaccess.h:113:9: warning: ‘rc’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  113 |  return rc;
      |         ^~
./arch/s390/include/asm/uaccess.h: In function ‘__get_user_fn’:
./arch/s390/include/asm/uaccess.h:143:9: warning: ‘rc’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  143 |  return rc;
      |         ^~

These functions are supposed to be always inlined. Mark it as such.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Miroslav Franc <mfranc@suse.cz>
---
 arch/s390/include/asm/uaccess.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index bd2fd9a7821d..a470f1fa9f2a 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -83,7 +83,7 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n);
 	__rc;							\
 })
 
-static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
+static __always_inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 {
 	unsigned long spec = 0x810000UL;
 	int rc;
@@ -113,7 +113,7 @@ static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 	return rc;
 }
 
-static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
+static __always_inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 {
 	unsigned long spec = 0x81UL;
 	int rc;