linux-stable/net/wireless/sysfs.c
Johannes Berg a05829a722 cfg80211: avoid holding the RTNL when calling the driver
Currently, _everything_ in cfg80211 holds the RTNL, and if you
have a slow USB device (or a few) you can get some bad lock
contention on that.

Fix that by re-adding a mutex to each wiphy/rdev as we had at
some point, so we have locking for the wireless_dev lists and
all the other things in there, and also so that drivers still
don't have to worry too much about it (they still won't get
parallel calls for a single device).

Then, we can restrict the RTNL to a few cases where we add or
remove interfaces and really need the added protection. Some
of the global list management still also uses the RTNL, since
we need to have it anyway for netdev management, but we only
hold the RTNL for very short periods of time here.

Link: https://lore.kernel.org/r/20210122161942.81df9f5e047a.I4a8e1a60b18863ea8c5e6d3a0faeafb2d45b2f40@changeid
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> [marvell driver issues]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-01-26 11:55:50 +01:00

179 lines
4.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* This file provides /sys/class/ieee80211/<wiphy name>/
* and some default attributes.
*
* Copyright 2005-2006 Jiri Benc <jbenc@suse.cz>
* Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
* Copyright (C) 2020-2021 Intel Corporation
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/nl80211.h>
#include <linux/rtnetlink.h>
#include <net/cfg80211.h>
#include "sysfs.h"
#include "core.h"
#include "rdev-ops.h"
static inline struct cfg80211_registered_device *dev_to_rdev(
struct device *dev)
{
return container_of(dev, struct cfg80211_registered_device, wiphy.dev);
}
#define SHOW_FMT(name, fmt, member) \
static ssize_t name ## _show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
return sprintf(buf, fmt "\n", dev_to_rdev(dev)->member); \
} \
static DEVICE_ATTR_RO(name)
SHOW_FMT(index, "%d", wiphy_idx);
SHOW_FMT(macaddress, "%pM", wiphy.perm_addr);
SHOW_FMT(address_mask, "%pM", wiphy.addr_mask);
static ssize_t name_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct wiphy *wiphy = &dev_to_rdev(dev)->wiphy;
return sprintf(buf, "%s\n", wiphy_name(wiphy));
}
static DEVICE_ATTR_RO(name);
static ssize_t addresses_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct wiphy *wiphy = &dev_to_rdev(dev)->wiphy;
char *start = buf;
int i;
if (!wiphy->addresses)
return sprintf(buf, "%pM\n", wiphy->perm_addr);
for (i = 0; i < wiphy->n_addresses; i++)
buf += sprintf(buf, "%pM\n", wiphy->addresses[i].addr);
return buf - start;
}
static DEVICE_ATTR_RO(addresses);
static struct attribute *ieee80211_attrs[] = {
&dev_attr_index.attr,
&dev_attr_macaddress.attr,
&dev_attr_address_mask.attr,
&dev_attr_addresses.attr,
&dev_attr_name.attr,
NULL,
};
ATTRIBUTE_GROUPS(ieee80211);
static void wiphy_dev_release(struct device *dev)
{
struct cfg80211_registered_device *rdev = dev_to_rdev(dev);
cfg80211_dev_free(rdev);
}
static int wiphy_uevent(struct device *dev, struct kobj_uevent_env *env)
{
/* TODO, we probably need stuff here */
return 0;
}
#ifdef CONFIG_PM_SLEEP
static void cfg80211_leave_all(struct cfg80211_registered_device *rdev)
{
struct wireless_dev *wdev;
list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list)
cfg80211_leave(rdev, wdev);
}
static int wiphy_suspend(struct device *dev)
{
struct cfg80211_registered_device *rdev = dev_to_rdev(dev);
int ret = 0;
rdev->suspend_at = ktime_get_boottime_seconds();
rtnl_lock();
wiphy_lock(&rdev->wiphy);
if (rdev->wiphy.registered) {
if (!rdev->wiphy.wowlan_config) {
cfg80211_leave_all(rdev);
cfg80211_process_rdev_events(rdev);
}
if (rdev->ops->suspend)
ret = rdev_suspend(rdev, rdev->wiphy.wowlan_config);
if (ret == 1) {
/* Driver refuse to configure wowlan */
cfg80211_leave_all(rdev);
cfg80211_process_rdev_events(rdev);
ret = rdev_suspend(rdev, NULL);
}
}
wiphy_unlock(&rdev->wiphy);
rtnl_unlock();
return ret;
}
static int wiphy_resume(struct device *dev)
{
struct cfg80211_registered_device *rdev = dev_to_rdev(dev);
int ret = 0;
/* Age scan results with time spent in suspend */
cfg80211_bss_age(rdev, ktime_get_boottime_seconds() - rdev->suspend_at);
rtnl_lock();
wiphy_lock(&rdev->wiphy);
if (rdev->wiphy.registered && rdev->ops->resume)
ret = rdev_resume(rdev);
wiphy_unlock(&rdev->wiphy);
rtnl_unlock();
return ret;
}
static SIMPLE_DEV_PM_OPS(wiphy_pm_ops, wiphy_suspend, wiphy_resume);
#define WIPHY_PM_OPS (&wiphy_pm_ops)
#else
#define WIPHY_PM_OPS NULL
#endif
static const void *wiphy_namespace(struct device *d)
{
struct wiphy *wiphy = container_of(d, struct wiphy, dev);
return wiphy_net(wiphy);
}
struct class ieee80211_class = {
.name = "ieee80211",
.owner = THIS_MODULE,
.dev_release = wiphy_dev_release,
.dev_groups = ieee80211_groups,
.dev_uevent = wiphy_uevent,
.pm = WIPHY_PM_OPS,
.ns_type = &net_ns_type_operations,
.namespace = wiphy_namespace,
};
int wiphy_sysfs_init(void)
{
return class_register(&ieee80211_class);
}
void wiphy_sysfs_exit(void)
{
class_unregister(&ieee80211_class);
}