autofs: improve ioctl sbi checks
authorIan Kent <raven@themaw.net>
Thu, 3 Jan 2019 23:27:33 +0000 (15:27 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 4 Jan 2019 21:13:46 +0000 (13:13 -0800)
commit55f0d8205dc6399826332c21bc56626868cd453d
tree9a15cf912445e21d9ad3fb87f087a89185313191
parent7c8f71935a65a584c48cbe478aaffc52292d6e00
autofs: improve ioctl sbi checks

Al Viro made some suggestions to improve the implementation of commit
0633da48f0 ("fix autofs_sbi() does not check super block type").

The check is unnecessary 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.

[akpm@linux-foundation.org: declare autofs_fs_type in .h, not .c]
Link: http://lkml.kernel.org/r/154296970987.9889.1597442413573683096.stgit@pluto-themaw-net
Signed-off-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: Linus Torvalds <torvalds@linux-foundation.org>
fs/autofs/autofs_i.h
fs/autofs/dev-ioctl.c
fs/autofs/init.c