/* This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Authors:
 * Alexander Aring <aar@pengutronix.de>
 *
 * Based on: net/wireless/sysfs.c
 */

#include <linux/device.h>
#include <linux/rtnetlink.h>

#include <net/cfg802154.h>

#include "core.h"
#include "sysfs.h"
#include "rdev-ops.h"

static inline struct cfg802154_registered_device *
dev_to_rdev(struct device *dev)
{
	return container_of(dev, struct cfg802154_registered_device,
			    wpan_phy.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", wpan_phy_idx);

static ssize_t name_show(struct device *dev,
			 struct device_attribute *attr,
			 char *buf)
{
	struct wpan_phy *wpan_phy = &dev_to_rdev(dev)->wpan_phy;

	return sprintf(buf, "%s\n", dev_name(&wpan_phy->dev));
}
static DEVICE_ATTR_RO(name);

static void wpan_phy_release(struct device *dev)
{
	struct cfg802154_registered_device *rdev = dev_to_rdev(dev);

	cfg802154_dev_free(rdev);
}

static struct attribute *pmib_attrs[] = {
	&dev_attr_index.attr,
	&dev_attr_name.attr,
	NULL,
};
ATTRIBUTE_GROUPS(pmib);

#ifdef CONFIG_PM_SLEEP
static int wpan_phy_suspend(struct device *dev)
{
	struct cfg802154_registered_device *rdev = dev_to_rdev(dev);
	int ret = 0;

	if (rdev->ops->suspend) {
		rtnl_lock();
		ret = rdev_suspend(rdev);
		rtnl_unlock();
	}

	return ret;
}

static int wpan_phy_resume(struct device *dev)
{
	struct cfg802154_registered_device *rdev = dev_to_rdev(dev);
	int ret = 0;

	if (rdev->ops->resume) {
		rtnl_lock();
		ret = rdev_resume(rdev);
		rtnl_unlock();
	}

	return ret;
}

static SIMPLE_DEV_PM_OPS(wpan_phy_pm_ops, wpan_phy_suspend, wpan_phy_resume);
#define WPAN_PHY_PM_OPS (&wpan_phy_pm_ops)
#else
#define WPAN_PHY_PM_OPS NULL
#endif

struct class wpan_phy_class = {
	.name = "ieee802154",
	.dev_release = wpan_phy_release,
	.dev_groups = pmib_groups,
	.pm = WPAN_PHY_PM_OPS,
};

int wpan_phy_sysfs_init(void)
{
	return class_register(&wpan_phy_class);
}

void wpan_phy_sysfs_exit(void)
{
	class_unregister(&wpan_phy_class);
}
ch' size='10' name='q' value=''/>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=966d2b04e070bc040319aaebfec09e0144dc3341'>drivers</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb?id=966d2b04e070bc040319aaebfec09e0144dc3341'>usb</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget?id=966d2b04e070bc040319aaebfec09e0144dc3341'>gadget</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/udc?id=966d2b04e070bc040319aaebfec09e0144dc3341'>udc</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/udc/trace.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>trace.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='966d2b04e070bc040319aaebfec09e0144dc3341'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Douglas Miller &lt;dougmill@linux.vnet.ibm.com&gt;</td><td class='right'>2017-01-28 06:42:20 -0600</td></tr>
<tr><th>committer</th><td>Tejun Heo &lt;tj@kernel.org&gt;</td><td class='right'>2017-01-28 07:49:42 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/udc/trace.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>966d2b04e070bc040319aaebfec09e0144dc3341</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/gadget/udc/trace.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>4b96156e3d1dd4dfd6039b7c219c9dc4616da52d</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/gadget/udc/trace.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>drivers/usb/gadget/udc/trace.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/udc/trace.h?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/gadget/udc/trace.h?id=966d2b04e070bc040319aaebfec09e0144dc3341&amp;id2=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>diff</a>)</td></tr></table>
<div class='commit-subject'>percpu-refcount: fix reference leak during percpu-atomic transition</div><div class='commit-msg'>percpu_ref_tryget() and percpu_ref_tryget_live() should return
"true" IFF they acquire a reference. But the return value from
atomic_long_inc_not_zero() is a long and may have high bits set,
e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines
is bool so the reference may actually be acquired but the routines
return "false" which results in a reference leak since the caller
assumes it does not need to do a corresponding percpu_ref_put().

This was seen when performing CPU hotplug during I/O, as hangs in
blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start)
raced with percpu_ref_tryget (blk_mq_timeout_work).
Sample stack trace:

__switch_to+0x2c0/0x450
__schedule+0x2f8/0x970
schedule+0x48/0xc0
blk_mq_freeze_queue_wait+0x94/0x120
blk_mq_queue_reinit_work+0xb8/0x180
blk_mq_queue_reinit_prepare+0x84/0xa0
cpuhp_invoke_callback+0x17c/0x600
cpuhp_up_callbacks+0x58/0x150
_cpu_up+0xf0/0x1c0
do_cpu_up+0x120/0x150
cpu_subsys_online+0x64/0xe0
device_online+0xb4/0x120
online_store+0xb4/0xc0
dev_attr_store+0x68/0xa0
sysfs_kf_write+0x80/0xb0
kernfs_fop_write+0x17c/0x250
__vfs_write+0x6c/0x1e0
vfs_write+0xd0/0x270
SyS_write+0x6c/0x110
system_call+0x38/0xe0

Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS,
and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests.
However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0
and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set.

The fix is to make the tryget routines use an actual boolean internally instead
of the atomic long result truncated to a int.

Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints
Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751
Signed-off-by: Douglas Miller &lt;dougmill@linux.vnet.ibm.com&gt;
Reviewed-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints")
Cc: stable@vger.kernel.org # v3.18+
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>Diffstat</a> (limited to 'drivers/usb/gadget/udc/trace.h')</div><table summary='diffstat' class='diffstat'>