On Fri, 2018-11-23 at 15:29 -0800, Andrew Morton wrote: > On Fri, 23 Nov 2018 18:41:50 +0800 Ian Kent <raven@xxxxxxxxxx> wrote: > > > Al Viro made some suggestions to improve the implementation > > of commit 0633da48f0 "fix autofs_sbi() does not check super > > block type". > > > > The check is unnessesary in all cases except for ioctl usage > > so placing the check in the super block accessor function > > adds a small overhead to the common case where it isn't > > needed. > > > > So it's sufficient to do this in the ioctl code only. > > > > Also the check in the ioctl code is needlessly complex. > > > > ... > > > > --- a/fs/autofs/dev-ioctl.c > > +++ b/fs/autofs/dev-ioctl.c > > @@ -14,6 +14,8 @@ > > > > #include "autofs_i.h" > > > > +extern struct file_system_type autofs_fs_type; > > + > > /* > > * This module implements an interface for routing autofs ioctl control > > * commands via a miscellaneous device file. > > It's naughty to declare externs in C files, for various reasons. Is > this OK? OK, I understand the reasoning I guess. The change below is fine. Thanks, Ian. > > --- a/fs/autofs/autofs_i.h~autofs-improve-ioctl-sbi-checks-fix > +++ a/fs/autofs/autofs_i.h > @@ -42,6 +42,8 @@ > #endif > #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__ > > +extern struct file_system_type autofs_fs_type; > + > /* > * Unified info structure. This is pointed to by both the dentry and > * inode structures. Each file in the filesystem has an instance of this > --- a/fs/autofs/dev-ioctl.c~autofs-improve-ioctl-sbi-checks-fix > +++ a/fs/autofs/dev-ioctl.c > @@ -14,8 +14,6 @@ > > #include "autofs_i.h" > > -extern struct file_system_type autofs_fs_type; > - > /* > * This module implements an interface for routing autofs ioctl control > * commands via a miscellaneous device file. > _ >
