sysfs: sysfs_setattr remove unnecessary permission check.

inode_change_ok already clears the SGID bit when necessary
so there is no reason for sysfs_setattr to carry code to do
the same, and it is good to kill the extra copy because when
I moved the code last in certain corner cases the code will
look at the wrong gid.

Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/sysfs/inode.c

@@ -117,10 +117,6 @@ int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
 		return error;
 
 	iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
-	if (iattr->ia_valid & ATTR_MODE) {
-		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
-			iattr->ia_mode &= ~S_ISGID;
-	}
 
 	error = inode_setattr(inode, iattr);
 	if (error)