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, 25 deletions

diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
index b008266e91ea..9757f1fc104f 100644
--- a/drivers/net/slip/slip.c
+++ b/drivers/net/slip/slip.c
@@ -79,7 +79,6 @@
 #include <linux/rtnetlink.h>
 #include <linux/if_arp.h>
 #include <linux/if_slip.h>
-#include <linux/compat.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/slab.h>
@@ -1167,27 +1166,6 @@ static int slip_ioctl(struct tty_struct *tty, struct file *file,
 	}
 }
 
-#ifdef CONFIG_COMPAT
-static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
-					unsigned int cmd, unsigned long arg)
-{
-	switch (cmd) {
-	case SIOCGIFNAME:
-	case SIOCGIFENCAP:
-	case SIOCSIFENCAP:
-	case SIOCSIFHWADDR:
-	case SIOCSKEEPALIVE:
-	case SIOCGKEEPALIVE:
-	case SIOCSOUTFILL:
-	case SIOCGOUTFILL:
-		return slip_ioctl(tty, file, cmd,
-				  (unsigned long)compat_ptr(arg));
-	}
-
-	return -ENOIOCTLCMD;
-}
-#endif
-
 /* VSV changes start here */
 #ifdef CONFIG_SLIP_SMART
 /* function do_ioctl called from net/core/dev.c
@@ -1280,9 +1258,6 @@ static struct tty_ldisc_ops sl_ldisc = {
 	.close	 	= slip_close,
 	.hangup	 	= slip_hangup,
 	.ioctl		= slip_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl	= slip_compat_ioctl,
-#endif
 	.receive_buf	= slip_receive_buf,
 	.write_wakeup	= slip_write_wakeup,
 };