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authorAl Viro <viro@zeniv.linux.org.uk>2018-09-13 22:12:15 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2018-10-13 00:50:53 -0400
commitf0193d3ea73b966b5dbfa272c8228d743b8856ef (patch)
treec882a171c8706f274a7e09d8f7297c36ed750e34 /drivers/tty/tty_io.c
parent7ee329655189f32f0c17e0bad60c23a69b003e9e (diff)
change semantics of ldisc ->compat_ioctl()
First of all, make it return int. Returning long when native method had never allowed that is ridiculous and inconvenient. More importantly, change the caller; if ldisc ->compat_ioctl() is NULL or returns -ENOIOCTLCMD, tty_compat_ioctl() will try to feed cmd and compat_ptr(arg) to ldisc's native ->ioctl(). That simplifies ->compat_ioctl() instances quite a bit - they only need to deal with ioctls that are neither generic tty ones (those would get shunted off to tty_ioctl()) nor simple compat pointer ones. Note that something like TCFLSH won't reach ->compat_ioctl(), even if ldisc ->ioctl() does handle it - it will be recognized earlier and passed to tty_ioctl() (and ultimately - ldisc ->ioctl()). For many ldiscs it means that NULL ->compat_ioctl() does the right thing. Those where it won't serve (see e.g. n_r3964.c) are also easily dealt with - we need to handle the numeric-argument ioctls (calling the native instance) and, if such would exist, the ioctls that need layout conversion, etc. All in-tree ldiscs dealt with. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r--drivers/tty/tty_io.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 1a55c3e20299..cd8df45f09d9 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2824,6 +2824,9 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
return hung_up_tty_compat_ioctl(file, cmd, arg);
if (ld->ops->compat_ioctl)
retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
+ if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
+ retval = ld->ops->ioctl(tty, file,
+ (unsigned long)compat_ptr(cmd), arg);
tty_ldisc_deref(ld);
return retval;