fs: change return values from -EACCES to -EPERM

According to SUSv3:

[EACCES] Permission denied. An attempt was made to access a file in a way
forbidden by its file access permissions.

[EPERM] Operation not permitted. An attempt was made to perform an operation
limited to processes with appropriate privileges or to the owner of a file
or other resource.

So -EPERM should be returned if capability checks fails.

Strictly speaking this is an API change since the error code user sees is
altered.

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9d96255..f3b133d 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1711,7 +1711,7 @@
 		return -ECHILD;
 
 	if (!capable(CAP_SYS_ADMIN)) {
-		status = -EACCES;
+		status = -EPERM;
 		goto out_notask;
 	}
 
@@ -1844,7 +1844,7 @@
 	struct dentry *result;
 	struct mm_struct *mm;
 
-	result = ERR_PTR(-EACCES);
+	result = ERR_PTR(-EPERM);
 	if (!capable(CAP_SYS_ADMIN))
 		goto out;
 
@@ -1900,7 +1900,7 @@
 	ino_t ino;
 	int ret;
 
-	ret = -EACCES;
+	ret = -EPERM;
 	if (!capable(CAP_SYS_ADMIN))
 		goto out;