![Neil Horman](/assets/img/avatar_default.png)
A deadlock was reported to me recently that occured when netconsole was being used in a virtual guest. If the virtio_net driver was removed while netconsole was setup to use an interface that was driven by that driver, the guest deadlocked. No backtrace was provided because netconsole was the only console configured, but it became clear pretty quickly what the problem was. In netconsole_netdev_event, if we get an unregister event, we call __netpoll_cleanup with the target_list_lock held and irqs disabled. __netpoll_cleanup can, if pending netpoll packets are waiting call cancel_delayed_work_sync, which is a sleeping path. the might_sleep call in that path gets triggered, causing a console warning to be issued. The netconsole write handler of course tries to take the target_list_lock again, which we already hold, causing deadlock. The fix is pretty striaghtforward. Simply drop the target_list_lock and re-enable irqs prior to calling __netpoll_cleanup, the re-acquire the lock, and restart the loop. Confirmed by myself to fix the problem reported. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: "David S. Miller" <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
842 lines
21 KiB
C
842 lines
21 KiB
C
/*
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* linux/drivers/net/netconsole.c
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*
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* Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
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*
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* This file contains the implementation of an IRQ-safe, crash-safe
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* kernel console implementation that outputs kernel messages to the
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* network.
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*
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* Modification history:
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*
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* 2001-09-17 started by Ingo Molnar.
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* 2003-08-11 2.6 port by Matt Mackall
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* simplified options
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* generic card hooks
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* works non-modular
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* 2003-09-07 rewritten with netpoll api
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*/
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/****************************************************************
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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****************************************************************/
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/console.h>
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#include <linux/moduleparam.h>
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#include <linux/string.h>
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#include <linux/netpoll.h>
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#include <linux/inet.h>
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#include <linux/configfs.h>
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MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
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MODULE_DESCRIPTION("Console driver for network interfaces");
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MODULE_LICENSE("GPL");
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#define MAX_PARAM_LENGTH 256
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#define MAX_PRINT_CHUNK 1000
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static char config[MAX_PARAM_LENGTH];
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module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
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MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
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#ifndef MODULE
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static int __init option_setup(char *opt)
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{
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strlcpy(config, opt, MAX_PARAM_LENGTH);
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return 1;
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}
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__setup("netconsole=", option_setup);
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#endif /* MODULE */
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/* Linked list of all configured targets */
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static LIST_HEAD(target_list);
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/* This needs to be a spinlock because write_msg() cannot sleep */
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static DEFINE_SPINLOCK(target_list_lock);
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/**
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* struct netconsole_target - Represents a configured netconsole target.
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* @list: Links this target into the target_list.
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* @item: Links us into the configfs subsystem hierarchy.
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* @enabled: On / off knob to enable / disable target.
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* Visible from userspace (read-write).
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* We maintain a strict 1:1 correspondence between this and
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* whether the corresponding netpoll is active or inactive.
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* Also, other parameters of a target may be modified at
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* runtime only when it is disabled (enabled == 0).
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* @np: The netpoll structure for this target.
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* Contains the other userspace visible parameters:
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* dev_name (read-write)
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* local_port (read-write)
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* remote_port (read-write)
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* local_ip (read-write)
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* remote_ip (read-write)
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* local_mac (read-only)
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* remote_mac (read-write)
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*/
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struct netconsole_target {
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struct list_head list;
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#ifdef CONFIG_NETCONSOLE_DYNAMIC
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struct config_item item;
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#endif
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int enabled;
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struct netpoll np;
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};
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#ifdef CONFIG_NETCONSOLE_DYNAMIC
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static struct configfs_subsystem netconsole_subsys;
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static int __init dynamic_netconsole_init(void)
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{
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config_group_init(&netconsole_subsys.su_group);
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mutex_init(&netconsole_subsys.su_mutex);
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return configfs_register_subsystem(&netconsole_subsys);
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}
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static void __exit dynamic_netconsole_exit(void)
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{
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configfs_unregister_subsystem(&netconsole_subsys);
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}
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/*
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* Targets that were created by parsing the boot/module option string
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* do not exist in the configfs hierarchy (and have NULL names) and will
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* never go away, so make these a no-op for them.
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*/
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static void netconsole_target_get(struct netconsole_target *nt)
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{
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if (config_item_name(&nt->item))
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config_item_get(&nt->item);
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}
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static void netconsole_target_put(struct netconsole_target *nt)
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{
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if (config_item_name(&nt->item))
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config_item_put(&nt->item);
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}
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#else /* !CONFIG_NETCONSOLE_DYNAMIC */
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static int __init dynamic_netconsole_init(void)
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{
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return 0;
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}
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static void __exit dynamic_netconsole_exit(void)
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{
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}
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/*
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* No danger of targets going away from under us when dynamic
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* reconfigurability is off.
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*/
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static void netconsole_target_get(struct netconsole_target *nt)
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{
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}
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static void netconsole_target_put(struct netconsole_target *nt)
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{
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}
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#endif /* CONFIG_NETCONSOLE_DYNAMIC */
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/* Allocate new target (from boot/module param) and setup netpoll for it */
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static struct netconsole_target *alloc_param_target(char *target_config)
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{
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int err = -ENOMEM;
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struct netconsole_target *nt;
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/*
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* Allocate and initialize with defaults.
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* Note that these targets get their config_item fields zeroed-out.
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*/
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nt = kzalloc(sizeof(*nt), GFP_KERNEL);
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if (!nt) {
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printk(KERN_ERR "netconsole: failed to allocate memory\n");
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goto fail;
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}
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nt->np.name = "netconsole";
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strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
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nt->np.local_port = 6665;
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nt->np.remote_port = 6666;
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memset(nt->np.remote_mac, 0xff, ETH_ALEN);
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/* Parse parameters and setup netpoll */
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err = netpoll_parse_options(&nt->np, target_config);
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if (err)
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goto fail;
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err = netpoll_setup(&nt->np);
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if (err)
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goto fail;
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nt->enabled = 1;
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return nt;
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fail:
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kfree(nt);
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return ERR_PTR(err);
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}
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/* Cleanup netpoll for given target (from boot/module param) and free it */
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static void free_param_target(struct netconsole_target *nt)
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{
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netpoll_cleanup(&nt->np);
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kfree(nt);
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}
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#ifdef CONFIG_NETCONSOLE_DYNAMIC
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/*
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* Our subsystem hierarchy is:
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*
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* /sys/kernel/config/netconsole/
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* |
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* <target>/
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* | enabled
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* | dev_name
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* | local_port
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* | remote_port
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* | local_ip
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* | remote_ip
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* | local_mac
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* | remote_mac
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* |
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* <target>/...
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*/
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struct netconsole_target_attr {
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struct configfs_attribute attr;
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ssize_t (*show)(struct netconsole_target *nt,
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char *buf);
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ssize_t (*store)(struct netconsole_target *nt,
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const char *buf,
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size_t count);
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};
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static struct netconsole_target *to_target(struct config_item *item)
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{
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return item ?
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container_of(item, struct netconsole_target, item) :
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NULL;
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}
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/*
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* Wrapper over simple_strtol (base 10) with sanity and range checking.
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* We return (signed) long only because we may want to return errors.
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* Do not use this to convert numbers that are allowed to be negative.
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*/
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static long strtol10_check_range(const char *cp, long min, long max)
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{
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long ret;
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char *p = (char *) cp;
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WARN_ON(min < 0);
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WARN_ON(max < min);
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ret = simple_strtol(p, &p, 10);
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if (*p && (*p != '\n')) {
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printk(KERN_ERR "netconsole: invalid input\n");
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return -EINVAL;
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}
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if ((ret < min) || (ret > max)) {
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printk(KERN_ERR "netconsole: input %ld must be between "
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"%ld and %ld\n", ret, min, max);
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return -EINVAL;
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}
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return ret;
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}
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/*
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* Attribute operations for netconsole_target.
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*/
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static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
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}
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static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
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}
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static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
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}
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static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
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}
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static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
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}
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static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
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}
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static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
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{
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struct net_device *dev = nt->np.dev;
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static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
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return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
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}
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static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
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}
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/*
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* This one is special -- targets created through the configfs interface
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* are not enabled (and the corresponding netpoll activated) by default.
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* The user is expected to set the desired parameters first (which
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* would enable him to dynamically add new netpoll targets for new
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* network interfaces as and when they come up).
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*/
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static ssize_t store_enabled(struct netconsole_target *nt,
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const char *buf,
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size_t count)
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{
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int err;
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long enabled;
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enabled = strtol10_check_range(buf, 0, 1);
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if (enabled < 0)
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return enabled;
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if (enabled) { /* 1 */
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/*
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* Skip netpoll_parse_options() -- all the attributes are
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* already configured via configfs. Just print them out.
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*/
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netpoll_print_options(&nt->np);
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err = netpoll_setup(&nt->np);
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if (err)
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return err;
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printk(KERN_INFO "netconsole: network logging started\n");
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} else { /* 0 */
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netpoll_cleanup(&nt->np);
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}
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nt->enabled = enabled;
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return strnlen(buf, count);
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}
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static ssize_t store_dev_name(struct netconsole_target *nt,
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const char *buf,
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size_t count)
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{
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size_t len;
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if (nt->enabled) {
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printk(KERN_ERR "netconsole: target (%s) is enabled, "
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"disable to update parameters\n",
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config_item_name(&nt->item));
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return -EINVAL;
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}
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strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
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/* Get rid of possible trailing newline from echo(1) */
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len = strnlen(nt->np.dev_name, IFNAMSIZ);
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if (nt->np.dev_name[len - 1] == '\n')
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nt->np.dev_name[len - 1] = '\0';
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return strnlen(buf, count);
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}
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static ssize_t store_local_port(struct netconsole_target *nt,
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const char *buf,
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size_t count)
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{
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long local_port;
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#define __U16_MAX ((__u16) ~0U)
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if (nt->enabled) {
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printk(KERN_ERR "netconsole: target (%s) is enabled, "
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"disable to update parameters\n",
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config_item_name(&nt->item));
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return -EINVAL;
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}
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local_port = strtol10_check_range(buf, 0, __U16_MAX);
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if (local_port < 0)
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return local_port;
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nt->np.local_port = local_port;
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return strnlen(buf, count);
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}
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static ssize_t store_remote_port(struct netconsole_target *nt,
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const char *buf,
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size_t count)
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{
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long remote_port;
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#define __U16_MAX ((__u16) ~0U)
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if (nt->enabled) {
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printk(KERN_ERR "netconsole: target (%s) is enabled, "
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"disable to update parameters\n",
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config_item_name(&nt->item));
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return -EINVAL;
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}
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remote_port = strtol10_check_range(buf, 0, __U16_MAX);
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if (remote_port < 0)
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return remote_port;
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nt->np.remote_port = remote_port;
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return strnlen(buf, count);
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}
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static ssize_t store_local_ip(struct netconsole_target *nt,
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const char *buf,
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size_t count)
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{
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if (nt->enabled) {
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printk(KERN_ERR "netconsole: target (%s) is enabled, "
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"disable to update parameters\n",
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config_item_name(&nt->item));
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return -EINVAL;
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}
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nt->np.local_ip = in_aton(buf);
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return strnlen(buf, count);
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}
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static ssize_t store_remote_ip(struct netconsole_target *nt,
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const char *buf,
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size_t count)
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{
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if (nt->enabled) {
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printk(KERN_ERR "netconsole: target (%s) is enabled, "
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"disable to update parameters\n",
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config_item_name(&nt->item));
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return -EINVAL;
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}
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nt->np.remote_ip = in_aton(buf);
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return strnlen(buf, count);
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}
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static ssize_t store_remote_mac(struct netconsole_target *nt,
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const char *buf,
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size_t count)
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{
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u8 remote_mac[ETH_ALEN];
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char *p = (char *) buf;
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int i;
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if (nt->enabled) {
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printk(KERN_ERR "netconsole: target (%s) is enabled, "
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"disable to update parameters\n",
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config_item_name(&nt->item));
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return -EINVAL;
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}
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for (i = 0; i < ETH_ALEN - 1; i++) {
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remote_mac[i] = simple_strtoul(p, &p, 16);
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if (*p != ':')
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goto invalid;
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p++;
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}
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remote_mac[ETH_ALEN - 1] = simple_strtoul(p, &p, 16);
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if (*p && (*p != '\n'))
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goto invalid;
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memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
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return strnlen(buf, count);
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invalid:
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printk(KERN_ERR "netconsole: invalid input\n");
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return -EINVAL;
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}
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/*
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* Attribute definitions for netconsole_target.
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*/
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#define NETCONSOLE_TARGET_ATTR_RO(_name) \
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static struct netconsole_target_attr netconsole_target_##_name = \
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__CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
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#define NETCONSOLE_TARGET_ATTR_RW(_name) \
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static struct netconsole_target_attr netconsole_target_##_name = \
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__CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
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NETCONSOLE_TARGET_ATTR_RW(enabled);
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NETCONSOLE_TARGET_ATTR_RW(dev_name);
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NETCONSOLE_TARGET_ATTR_RW(local_port);
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NETCONSOLE_TARGET_ATTR_RW(remote_port);
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NETCONSOLE_TARGET_ATTR_RW(local_ip);
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NETCONSOLE_TARGET_ATTR_RW(remote_ip);
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NETCONSOLE_TARGET_ATTR_RO(local_mac);
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NETCONSOLE_TARGET_ATTR_RW(remote_mac);
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static struct configfs_attribute *netconsole_target_attrs[] = {
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&netconsole_target_enabled.attr,
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&netconsole_target_dev_name.attr,
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&netconsole_target_local_port.attr,
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&netconsole_target_remote_port.attr,
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&netconsole_target_local_ip.attr,
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|
&netconsole_target_remote_ip.attr,
|
|
&netconsole_target_local_mac.attr,
|
|
&netconsole_target_remote_mac.attr,
|
|
NULL,
|
|
};
|
|
|
|
/*
|
|
* Item operations and type for netconsole_target.
|
|
*/
|
|
|
|
static void netconsole_target_release(struct config_item *item)
|
|
{
|
|
kfree(to_target(item));
|
|
}
|
|
|
|
static ssize_t netconsole_target_attr_show(struct config_item *item,
|
|
struct configfs_attribute *attr,
|
|
char *buf)
|
|
{
|
|
ssize_t ret = -EINVAL;
|
|
struct netconsole_target *nt = to_target(item);
|
|
struct netconsole_target_attr *na =
|
|
container_of(attr, struct netconsole_target_attr, attr);
|
|
|
|
if (na->show)
|
|
ret = na->show(nt, buf);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t netconsole_target_attr_store(struct config_item *item,
|
|
struct configfs_attribute *attr,
|
|
const char *buf,
|
|
size_t count)
|
|
{
|
|
ssize_t ret = -EINVAL;
|
|
struct netconsole_target *nt = to_target(item);
|
|
struct netconsole_target_attr *na =
|
|
container_of(attr, struct netconsole_target_attr, attr);
|
|
|
|
if (na->store)
|
|
ret = na->store(nt, buf, count);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct configfs_item_operations netconsole_target_item_ops = {
|
|
.release = netconsole_target_release,
|
|
.show_attribute = netconsole_target_attr_show,
|
|
.store_attribute = netconsole_target_attr_store,
|
|
};
|
|
|
|
static struct config_item_type netconsole_target_type = {
|
|
.ct_attrs = netconsole_target_attrs,
|
|
.ct_item_ops = &netconsole_target_item_ops,
|
|
.ct_owner = THIS_MODULE,
|
|
};
|
|
|
|
/*
|
|
* Group operations and type for netconsole_subsys.
|
|
*/
|
|
|
|
static struct config_item *make_netconsole_target(struct config_group *group,
|
|
const char *name)
|
|
{
|
|
unsigned long flags;
|
|
struct netconsole_target *nt;
|
|
|
|
/*
|
|
* Allocate and initialize with defaults.
|
|
* Target is disabled at creation (enabled == 0).
|
|
*/
|
|
nt = kzalloc(sizeof(*nt), GFP_KERNEL);
|
|
if (!nt) {
|
|
printk(KERN_ERR "netconsole: failed to allocate memory\n");
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
nt->np.name = "netconsole";
|
|
strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
|
|
nt->np.local_port = 6665;
|
|
nt->np.remote_port = 6666;
|
|
memset(nt->np.remote_mac, 0xff, ETH_ALEN);
|
|
|
|
/* Initialize the config_item member */
|
|
config_item_init_type_name(&nt->item, name, &netconsole_target_type);
|
|
|
|
/* Adding, but it is disabled */
|
|
spin_lock_irqsave(&target_list_lock, flags);
|
|
list_add(&nt->list, &target_list);
|
|
spin_unlock_irqrestore(&target_list_lock, flags);
|
|
|
|
return &nt->item;
|
|
}
|
|
|
|
static void drop_netconsole_target(struct config_group *group,
|
|
struct config_item *item)
|
|
{
|
|
unsigned long flags;
|
|
struct netconsole_target *nt = to_target(item);
|
|
|
|
spin_lock_irqsave(&target_list_lock, flags);
|
|
list_del(&nt->list);
|
|
spin_unlock_irqrestore(&target_list_lock, flags);
|
|
|
|
/*
|
|
* The target may have never been enabled, or was manually disabled
|
|
* before being removed so netpoll may have already been cleaned up.
|
|
*/
|
|
if (nt->enabled)
|
|
netpoll_cleanup(&nt->np);
|
|
|
|
config_item_put(&nt->item);
|
|
}
|
|
|
|
static struct configfs_group_operations netconsole_subsys_group_ops = {
|
|
.make_item = make_netconsole_target,
|
|
.drop_item = drop_netconsole_target,
|
|
};
|
|
|
|
static struct config_item_type netconsole_subsys_type = {
|
|
.ct_group_ops = &netconsole_subsys_group_ops,
|
|
.ct_owner = THIS_MODULE,
|
|
};
|
|
|
|
/* The netconsole configfs subsystem */
|
|
static struct configfs_subsystem netconsole_subsys = {
|
|
.su_group = {
|
|
.cg_item = {
|
|
.ci_namebuf = "netconsole",
|
|
.ci_type = &netconsole_subsys_type,
|
|
},
|
|
},
|
|
};
|
|
|
|
#endif /* CONFIG_NETCONSOLE_DYNAMIC */
|
|
|
|
/* Handle network interface device notifications */
|
|
static int netconsole_netdev_event(struct notifier_block *this,
|
|
unsigned long event,
|
|
void *ptr)
|
|
{
|
|
unsigned long flags;
|
|
struct netconsole_target *nt;
|
|
struct net_device *dev = ptr;
|
|
bool stopped = false;
|
|
|
|
if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
|
|
event == NETDEV_BONDING_DESLAVE || event == NETDEV_GOING_DOWN))
|
|
goto done;
|
|
|
|
spin_lock_irqsave(&target_list_lock, flags);
|
|
restart:
|
|
list_for_each_entry(nt, &target_list, list) {
|
|
netconsole_target_get(nt);
|
|
if (nt->np.dev == dev) {
|
|
switch (event) {
|
|
case NETDEV_CHANGENAME:
|
|
strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
|
|
break;
|
|
case NETDEV_UNREGISTER:
|
|
/*
|
|
* rtnl_lock already held
|
|
*/
|
|
if (nt->np.dev) {
|
|
spin_unlock_irqrestore(
|
|
&target_list_lock,
|
|
flags);
|
|
__netpoll_cleanup(&nt->np);
|
|
spin_lock_irqsave(&target_list_lock,
|
|
flags);
|
|
dev_put(nt->np.dev);
|
|
nt->np.dev = NULL;
|
|
netconsole_target_put(nt);
|
|
goto restart;
|
|
}
|
|
/* Fall through */
|
|
case NETDEV_GOING_DOWN:
|
|
case NETDEV_BONDING_DESLAVE:
|
|
nt->enabled = 0;
|
|
stopped = true;
|
|
break;
|
|
}
|
|
}
|
|
netconsole_target_put(nt);
|
|
}
|
|
spin_unlock_irqrestore(&target_list_lock, flags);
|
|
if (stopped && (event == NETDEV_UNREGISTER || event == NETDEV_BONDING_DESLAVE))
|
|
printk(KERN_INFO "netconsole: network logging stopped on "
|
|
"interface %s as it %s\n", dev->name,
|
|
event == NETDEV_UNREGISTER ? "unregistered" : "released slaves");
|
|
|
|
done:
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block netconsole_netdev_notifier = {
|
|
.notifier_call = netconsole_netdev_event,
|
|
};
|
|
|
|
static void write_msg(struct console *con, const char *msg, unsigned int len)
|
|
{
|
|
int frag, left;
|
|
unsigned long flags;
|
|
struct netconsole_target *nt;
|
|
const char *tmp;
|
|
|
|
/* Avoid taking lock and disabling interrupts unnecessarily */
|
|
if (list_empty(&target_list))
|
|
return;
|
|
|
|
spin_lock_irqsave(&target_list_lock, flags);
|
|
list_for_each_entry(nt, &target_list, list) {
|
|
netconsole_target_get(nt);
|
|
if (nt->enabled && netif_running(nt->np.dev)) {
|
|
/*
|
|
* We nest this inside the for-each-target loop above
|
|
* so that we're able to get as much logging out to
|
|
* at least one target if we die inside here, instead
|
|
* of unnecessarily keeping all targets in lock-step.
|
|
*/
|
|
tmp = msg;
|
|
for (left = len; left;) {
|
|
frag = min(left, MAX_PRINT_CHUNK);
|
|
netpoll_send_udp(&nt->np, tmp, frag);
|
|
tmp += frag;
|
|
left -= frag;
|
|
}
|
|
}
|
|
netconsole_target_put(nt);
|
|
}
|
|
spin_unlock_irqrestore(&target_list_lock, flags);
|
|
}
|
|
|
|
static struct console netconsole = {
|
|
.name = "netcon",
|
|
.flags = CON_ENABLED,
|
|
.write = write_msg,
|
|
};
|
|
|
|
static int __init init_netconsole(void)
|
|
{
|
|
int err;
|
|
struct netconsole_target *nt, *tmp;
|
|
unsigned long flags;
|
|
char *target_config;
|
|
char *input = config;
|
|
|
|
if (strnlen(input, MAX_PARAM_LENGTH)) {
|
|
while ((target_config = strsep(&input, ";"))) {
|
|
nt = alloc_param_target(target_config);
|
|
if (IS_ERR(nt)) {
|
|
err = PTR_ERR(nt);
|
|
goto fail;
|
|
}
|
|
/* Dump existing printks when we register */
|
|
netconsole.flags |= CON_PRINTBUFFER;
|
|
|
|
spin_lock_irqsave(&target_list_lock, flags);
|
|
list_add(&nt->list, &target_list);
|
|
spin_unlock_irqrestore(&target_list_lock, flags);
|
|
}
|
|
}
|
|
|
|
err = register_netdevice_notifier(&netconsole_netdev_notifier);
|
|
if (err)
|
|
goto fail;
|
|
|
|
err = dynamic_netconsole_init();
|
|
if (err)
|
|
goto undonotifier;
|
|
|
|
register_console(&netconsole);
|
|
printk(KERN_INFO "netconsole: network logging started\n");
|
|
|
|
return err;
|
|
|
|
undonotifier:
|
|
unregister_netdevice_notifier(&netconsole_netdev_notifier);
|
|
|
|
fail:
|
|
printk(KERN_ERR "netconsole: cleaning up\n");
|
|
|
|
/*
|
|
* Remove all targets and destroy them (only targets created
|
|
* from the boot/module option exist here). Skipping the list
|
|
* lock is safe here, and netpoll_cleanup() will sleep.
|
|
*/
|
|
list_for_each_entry_safe(nt, tmp, &target_list, list) {
|
|
list_del(&nt->list);
|
|
free_param_target(nt);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static void __exit cleanup_netconsole(void)
|
|
{
|
|
struct netconsole_target *nt, *tmp;
|
|
|
|
unregister_console(&netconsole);
|
|
dynamic_netconsole_exit();
|
|
unregister_netdevice_notifier(&netconsole_netdev_notifier);
|
|
|
|
/*
|
|
* Targets created via configfs pin references on our module
|
|
* and would first be rmdir(2)'ed from userspace. We reach
|
|
* here only when they are already destroyed, and only those
|
|
* created from the boot/module option are left, so remove and
|
|
* destroy them. Skipping the list lock is safe here, and
|
|
* netpoll_cleanup() will sleep.
|
|
*/
|
|
list_for_each_entry_safe(nt, tmp, &target_list, list) {
|
|
list_del(&nt->list);
|
|
free_param_target(nt);
|
|
}
|
|
}
|
|
|
|
module_init(init_netconsole);
|
|
module_exit(cleanup_netconsole);
|