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>

4 files changed, 0 insertions, 86 deletions

diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index d79a69dd2146..17e6dcd2eb42 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -34,7 +34,6 @@
 #include <linux/ip.h>
 #include <linux/tcp.h>
 #include <linux/semaphore.h>
-#include <linux/compat.h>
 #include <linux/refcount.h>
 
 #define SIXPACK_VERSION    "Revision: 0.3.0"
@@ -752,23 +751,6 @@ static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
 	return err;
 }
 
-#ifdef CONFIG_COMPAT
-static long sixpack_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:
-		return sixpack_ioctl(tty, file, cmd,
-				(unsigned long)compat_ptr(arg));
-	}
-
-	return -ENOIOCTLCMD;
-}
-#endif
-
 static struct tty_ldisc_ops sp_ldisc = {
 	.owner		= THIS_MODULE,
 	.magic		= TTY_LDISC_MAGIC,
@@ -776,9 +758,6 @@ static struct tty_ldisc_ops sp_ldisc = {
 	.open		= sixpack_open,
 	.close		= sixpack_close,
 	.ioctl		= sixpack_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl	= sixpack_compat_ioctl,
-#endif
 	.receive_buf	= sixpack_receive_buf,
 	.write_wakeup	= sixpack_write_wakeup,
 };
diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index 13e4c1eff353..802233d41b25 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -35,7 +35,6 @@
 #include <linux/skbuff.h>
 #include <linux/if_arp.h>
 #include <linux/jiffies.h>
-#include <linux/compat.h>
 
 #include <net/ax25.h>
 
@@ -875,23 +874,6 @@ static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
 	return err;
 }
 
-#ifdef CONFIG_COMPAT
-static long mkiss_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:
-		return mkiss_ioctl(tty, file, cmd,
-				   (unsigned long)compat_ptr(arg));
-	}
-
-	return -ENOIOCTLCMD;
-}
-#endif
-
 /*
  * Handle the 'receiver data ready' interrupt.
  * This function is called by the 'tty_io' module in the kernel when
@@ -966,9 +948,6 @@ static struct tty_ldisc_ops ax_ldisc = {
 	.open		= mkiss_open,
 	.close		= mkiss_close,
 	.ioctl		= mkiss_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl	= mkiss_compat_ioctl,
-#endif
 	.receive_buf	= mkiss_receive_buf,
 	.write_wakeup	= mkiss_write_wakeup
 };
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,
 };
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,
 };