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>

1 files changed, 0 insertions, 19 deletions

diff --git a/drivers/net/wan/x25_asy.c b/drivers/net/wan/x25_asy.c
index 74c06a5f586f..1098263ab862 100644
--- a/drivers/net/wan/x25_asy.c
+++ b/drivers/net/wan/x25_asy.c
@@ -33,7 +33,6 @@
 #include <linux/lapb.h>
 #include <linux/init.h>
 #include <linux/rtnetlink.h>
-#include <linux/compat.h>
 #include <linux/slab.h>
 #include <net/x25device.h>
 #include "x25_asy.h"
@@ -703,21 +702,6 @@ static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
 	}
 }
 
-#ifdef CONFIG_COMPAT
-static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
-			 unsigned int cmd,  unsigned long arg)
-{
-	switch (cmd) {
-	case SIOCGIFNAME:
-	case SIOCSIFHWADDR:
-		return x25_asy_ioctl(tty, file, cmd,
-				     (unsigned long)compat_ptr(arg));
-	}
-
-	return -ENOIOCTLCMD;
-}
-#endif
-
 static int x25_asy_open_dev(struct net_device *dev)
 {
 	struct x25_asy *sl = netdev_priv(dev);
@@ -769,9 +753,6 @@ static struct tty_ldisc_ops x25_ldisc = {
 	.open		= x25_asy_open_tty,
 	.close		= x25_asy_close_tty,
 	.ioctl		= x25_asy_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl	= x25_asy_compat_ioctl,
-#endif
 	.receive_buf	= x25_asy_receive_buf,
 	.write_wakeup	= x25_asy_write_wakeup,
 };