WSL2-Linux-Kernel/drivers/net/can/vcan.c

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Исходник Обычный вид История

/* vcan.c - Virtual CAN interface
*
* Copyright (c) 2002-2017 Volkswagen Group Electronic Research
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Volkswagen nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* Alternatively, provided that this notice is retained in full, this
* software may be distributed under the terms of the GNU General
* Public License ("GPL") version 2, in which case the provisions of the
* GPL apply INSTEAD OF those given above.
*
* The provided data structures and external interfaces from this code
* are not restricted to be used by modules with a GPL compatible license.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/can.h>
#include <linux/can/can-ml.h>
#include <linux/can/dev.h>
#include <linux/can/skb.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 11:04:11 +03:00
#include <linux/slab.h>
#include <net/rtnetlink.h>
#define DRV_NAME "vcan"
MODULE_DESCRIPTION("virtual CAN interface");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
MODULE_ALIAS_RTNL_LINK(DRV_NAME);
/* CAN test feature:
* Enable the echo on driver level for testing the CAN core echo modes.
* See Documentation/networking/can.rst for details.
*/
static bool echo; /* echo testing. Default: 0 (Off) */
module_param(echo, bool, 0444);
MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
struct net_device_stats *stats = &dev->stats;
stats->rx_packets++;
stats->rx_bytes += cfd->len;
skb->pkt_type = PACKET_BROADCAST;
skb->dev = dev;
skb->ip_summed = CHECKSUM_UNNECESSARY;
netif_rx_ni(skb);
}
static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
struct net_device_stats *stats = &dev->stats;
int loop;
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
stats->tx_packets++;
stats->tx_bytes += cfd->len;
/* set flag whether this packet has to be looped back */
loop = skb->pkt_type == PACKET_LOOPBACK;
if (!echo) {
/* no echo handling available inside this driver */
if (loop) {
/* only count the packets here, because the
* CAN core already did the echo for us
*/
stats->rx_packets++;
stats->rx_bytes += cfd->len;
}
consume_skb(skb);
return NETDEV_TX_OK;
}
/* perform standard echo handling for CAN network interfaces */
if (loop) {
skb = can_create_echo_skb(skb);
if (!skb)
return NETDEV_TX_OK;
/* receive with packet counting */
vcan_rx(skb, dev);
} else {
/* no looped packets => no counting */
consume_skb(skb);
}
return NETDEV_TX_OK;
}
static int vcan_change_mtu(struct net_device *dev, int new_mtu)
{
/* Do not allow changing the MTU while running */
if (dev->flags & IFF_UP)
return -EBUSY;
if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
return -EINVAL;
dev->mtu = new_mtu;
return 0;
}
static const struct net_device_ops vcan_netdev_ops = {
.ndo_start_xmit = vcan_tx,
.ndo_change_mtu = vcan_change_mtu,
};
static void vcan_setup(struct net_device *dev)
{
dev->type = ARPHRD_CAN;
dev->mtu = CANFD_MTU;
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->tx_queue_len = 0;
dev->flags = IFF_NOARP;
dev->ml_priv = netdev_priv(dev);
/* set flags according to driver capabilities */
if (echo)
dev->flags |= IFF_ECHO;
dev->netdev_ops = &vcan_netdev_ops;
net: Fix inconsistent teardown and release of private netdev state. Network devices can allocate reasources and private memory using netdev_ops->ndo_init(). However, the release of these resources can occur in one of two different places. Either netdev_ops->ndo_uninit() or netdev->destructor(). The decision of which operation frees the resources depends upon whether it is necessary for all netdev refs to be released before it is safe to perform the freeing. netdev_ops->ndo_uninit() presumably can occur right after the NETDEV_UNREGISTER notifier completes and the unicast and multicast address lists are flushed. netdev->destructor(), on the other hand, does not run until the netdev references all go away. Further complicating the situation is that netdev->destructor() almost universally does also a free_netdev(). This creates a problem for the logic in register_netdevice(). Because all callers of register_netdevice() manage the freeing of the netdev, and invoke free_netdev(dev) if register_netdevice() fails. If netdev_ops->ndo_init() succeeds, but something else fails inside of register_netdevice(), it does call ndo_ops->ndo_uninit(). But it is not able to invoke netdev->destructor(). This is because netdev->destructor() will do a free_netdev() and then the caller of register_netdevice() will do the same. However, this means that the resources that would normally be released by netdev->destructor() will not be. Over the years drivers have added local hacks to deal with this, by invoking their destructor parts by hand when register_netdevice() fails. Many drivers do not try to deal with this, and instead we have leaks. Let's close this hole by formalizing the distinction between what private things need to be freed up by netdev->destructor() and whether the driver needs unregister_netdevice() to perform the free_netdev(). netdev->priv_destructor() performs all actions to free up the private resources that used to be freed by netdev->destructor(), except for free_netdev(). netdev->needs_free_netdev is a boolean that indicates whether free_netdev() should be done at the end of unregister_netdevice(). Now, register_netdevice() can sanely release all resources after ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit() and netdev->priv_destructor(). And at the end of unregister_netdevice(), we invoke netdev->priv_destructor() and optionally call free_netdev(). Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-08 19:52:56 +03:00
dev->needs_free_netdev = true;
}
static struct rtnl_link_ops vcan_link_ops __read_mostly = {
.kind = DRV_NAME,
.priv_size = sizeof(struct can_ml_priv),
.setup = vcan_setup,
};
static __init int vcan_init_module(void)
{
pr_info("Virtual CAN interface driver\n");
if (echo)
pr_info("enabled echo on driver level.\n");
return rtnl_link_register(&vcan_link_ops);
}
static __exit void vcan_cleanup_module(void)
{
rtnl_link_unregister(&vcan_link_ops);
}
module_init(vcan_init_module);
module_exit(vcan_cleanup_module);