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From: Arnd Bergmann <arnd@kernel.org>
To: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Arnd Bergmann <arnd@arndb.de>,
	Cong Wang <cong.wang@bytedance.com>
Subject: [PATCH net-next v3 01/31] net: split out SIOCDEVPRIVATE handling from dev_ioctl
Date: Tue, 27 Jul 2021 15:44:47 +0200	[thread overview]
Message-ID: <20210727134517.1384504-2-arnd@kernel.org> (raw)
In-Reply-To: <20210727134517.1384504-1-arnd@kernel.org>

From: Arnd Bergmann <arnd@arndb.de>

SIOCDEVPRIVATE ioctl commands are mainly used in really old
drivers, and they have a number of problems:

- They hide behind the normal .ndo_do_ioctl function that
  is also used for other things in modern drivers, so it's
  hard to spot a driver that actually uses one of these

- Since drivers use a number different calling conventions,
  it is impossible to support compat mode for them in
  a generic way.

- With all drivers using the same 16 commands codes, there
  is no way to introspect the data being passed through
  things like strace.

Add a new net_device_ops callback pointer, to address the
first two of these. Separating them from .ndo_do_ioctl
makes it easy to grep for drivers with a .ndo_siocdevprivate
callback, and the unwieldy name hopefully makes it easier
to spot in code review.

By passing the ifreq structure and the ifr_data pointer
separately, it is no longer necessary to overload these,
and the driver can use either one for a given command.

Cc: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 Documentation/networking/netdevices.rst |  7 +++++++
 include/linux/netdevice.h               |  3 +++
 net/core/dev_ioctl.c                    | 25 ++++++++++++++++++++++---
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst
index 17bdcb746dcf..02f1faac839a 100644
--- a/Documentation/networking/netdevices.rst
+++ b/Documentation/networking/netdevices.rst
@@ -222,6 +222,13 @@ ndo_do_ioctl:
 	Synchronization: rtnl_lock() semaphore.
 	Context: process
 
+ndo_siocdevprivate:
+	Synchronization: rtnl_lock() semaphore.
+	Context: process
+
+	This is used to implement SIOCDEVPRIVATE ioctl helpers.
+	These should not be added to new drivers, so don't use.
+
 ndo_get_stats:
 	Synchronization: rtnl_lock() semaphore, dev_base_lock rwlock, or RCU.
 	Context: atomic (can't sleep under rwlock or RCU)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c871dc223dfa..670e1a8e5928 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1361,6 +1361,9 @@ struct net_device_ops {
 	int			(*ndo_validate_addr)(struct net_device *dev);
 	int			(*ndo_do_ioctl)(struct net_device *dev,
 					        struct ifreq *ifr, int cmd);
+	int			(*ndo_siocdevprivate)(struct net_device *dev,
+						      struct ifreq *ifr,
+						      void __user *data, int cmd);
 	int			(*ndo_set_config)(struct net_device *dev,
 					          struct ifmap *map);
 	int			(*ndo_change_mtu)(struct net_device *dev,
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 950e2fe5d56a..75e3e340d884 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -259,6 +259,23 @@ static int dev_do_ioctl(struct net_device *dev,
 	return err;
 }
 
+static int dev_siocdevprivate(struct net_device *dev,
+			      struct ifreq *ifr, unsigned int cmd)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	void __user *data = ifr->ifr_data;
+
+	if (ops->ndo_siocdevprivate) {
+		if (netif_device_present(dev))
+			return ops->ndo_siocdevprivate(dev, ifr, data, cmd);
+		else
+			return -ENODEV;
+	}
+
+	/* fall back to do_ioctl for drivers not yet converted */
+	return dev_do_ioctl(dev, ifr, cmd);
+}
+
 /*
  *	Perform the SIOCxIFxxx calls, inside rtnl_lock()
  */
@@ -336,9 +353,11 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
 	 *	Unknown or private ioctl
 	 */
 	default:
-		if ((cmd >= SIOCDEVPRIVATE &&
-		    cmd <= SIOCDEVPRIVATE + 15) ||
-		    cmd == SIOCBONDENSLAVE ||
+		if (cmd >= SIOCDEVPRIVATE &&
+		    cmd <= SIOCDEVPRIVATE + 15)
+			return dev_siocdevprivate(dev, ifr, cmd);
+
+		if (cmd == SIOCBONDENSLAVE ||
 		    cmd == SIOCBONDRELEASE ||
 		    cmd == SIOCBONDSETHWADDR ||
 		    cmd == SIOCBONDSLAVEINFOQUERY ||
-- 
2.29.2


  reply	other threads:[~2021-07-27 13:46 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-27 13:44 [PATCH net-next v3 00/31] ndo_ioctl rework Arnd Bergmann
2021-07-27 13:44 ` Arnd Bergmann [this message]
2021-07-27 13:44 ` [PATCH net-next v3 02/31] staging: rtlwifi: use siocdevprivate Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 03/31] staging: wlan-ng: " Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 04/31] hostap: use ndo_siocdevprivate Arnd Bergmann
2021-07-28  7:07   ` Kalle Valo
2021-07-27 13:44 ` [PATCH net-next v3 05/31] bridge: " Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 06/31] phonet: use siocdevprivate Arnd Bergmann
2021-07-27 16:03   ` Rémi Denis-Courmont
2021-07-27 13:44 ` [PATCH net-next v3 07/31] tulip: use ndo_siocdevprivate Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 08/31] bonding: use siocdevprivate Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 09/31] appletalk: use ndo_siocdevprivate Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 10/31] hamachi: " Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 11/31] tehuti: " Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 12/31] eql: " Arnd Bergmann
2021-07-27 13:44 ` [PATCH net-next v3 13/31] fddi: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 14/31] net: usb: " Arnd Bergmann
2021-07-28 13:02   ` Petko Manolov
2021-07-27 13:45 ` [PATCH net-next v3 15/31] slip/plip: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 16/31] qeth: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 17/31] cxgb3: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 18/31] hamradio: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 19/31] airo: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 20/31] ip_tunnel: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 21/31] hippi: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 22/31] sb1000: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 23/31] ppp: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 24/31] wan: " Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 25/31] wan: cosa: remove dead cosa_net_ioctl() function Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 26/31] dev_ioctl: pass SIOCDEVPRIVATE data separately Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 27/31] dev_ioctl: split out ndo_eth_ioctl Arnd Bergmann
2021-07-27 16:30   ` Jason Gunthorpe
2021-07-27 13:45 ` [PATCH net-next v3 28/31] net: split out ndo_siowandev ioctl Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 29/31] net: socket: return changed ifreq from SIOCDEVPRIVATE Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 30/31] net: bridge: move bridge ioctls out of .ndo_do_ioctl Arnd Bergmann
2021-07-27 13:45 ` [PATCH net-next v3 31/31] net: bonding: move ioctl handling to private ndo operation Arnd Bergmann
2021-07-27 20:00 ` [PATCH net-next v3 00/31] ndo_ioctl rework patchwork-bot+netdevbpf

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