/*
 * PCI Backend - Handle special overlays for broken devices.
 *
 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
 * Author: Chris Bookholt <hap10@epoch.ncsc.mil>
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include "pciback.h"
#include "conf_space.h"
#include "conf_space_quirks.h"

LIST_HEAD(xen_pcibk_quirks);
static inline const struct pci_device_id *
match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
{
	if ((id->vendor == PCI_ANY_ID || id->vendor == dev->vendor) &&
	    (id->device == PCI_ANY_ID || id->device == dev->device) &&
	    (id->subvendor == PCI_ANY_ID ||
				id->subvendor == dev->subsystem_vendor) &&
	    (id->subdevice == PCI_ANY_ID ||
				id->subdevice == dev->subsystem_device) &&
	    !((id->class ^ dev->class) & id->class_mask))
		return id;
	return NULL;
}

static struct xen_pcibk_config_quirk *xen_pcibk_find_quirk(struct pci_dev *dev)
{
	struct xen_pcibk_config_quirk *tmp_quirk;

	list_for_each_entry(tmp_quirk, &xen_pcibk_quirks, quirks_list)
		if (match_one_device(&tmp_quirk->devid, dev) != NULL)
			goto out;
	tmp_quirk = NULL;
	printk(KERN_DEBUG DRV_NAME
	       ": quirk didn't match any device known\n");
out:
	return tmp_quirk;
}

static inline void register_quirk(struct xen_pcibk_config_quirk *quirk)
{
	list_add_tail(&quirk->quirks_list, &xen_pcibk_quirks);
}

int xen_pcibk_field_is_dup(struct pci_dev *dev, unsigned int reg)
{
	int ret = 0;
	struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
	struct config_field_entry *cfg_entry;

	list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
		if (OFFSET(cfg_entry) == reg) {
			ret = 1;
			break;
		}
	}
	return ret;
}

int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field
				    *field)
{
	int err = 0;

	switch (field->size) {
	case 1:
		field->u.b.read = xen_pcibk_read_config_byte;
		field->u.b.write = xen_pcibk_write_config_byte;
		break;
	case 2:
		field->u.w.read = xen_pcibk_read_config_word;
		field->u.w.write = xen_pcibk_write_config_word;
		break;
	case 4:
		field->u.dw.read = xen_pcibk_read_config_dword;
		field->u.dw.write = xen_pcibk_write_config_dword;
		break;
	default:
		err = -EINVAL;
		goto out;
	}

	xen_pcibk_config_add_field(dev, field);

out:
	return err;
}

int xen_pcibk_config_quirks_init(struct pci_dev *dev)
{
	struct xen_pcibk_config_quirk *quirk;
	int ret = 0;

	quirk = kzalloc(sizeof(*quirk), GFP_ATOMIC);
	if (!quirk) {
		ret = -ENOMEM;
		goto out;
	}

	quirk->devid.vendor = dev->vendor;
	quirk->devid.device = dev->device;
	quirk->devid.subvendor = dev->subsystem_vendor;
	quirk->devid.subdevice = dev->subsystem_device;
	quirk->devid.class = 0;
	quirk->devid.class_mask = 0;
	quirk->devid.driver_data = 0UL;

	quirk->pdev = dev;

	register_quirk(quirk);
out:
	return ret;
}

void xen_pcibk_config_field_free(struct config_field *field)
{
	kfree(field);
}

int xen_pcibk_config_quirk_release(struct pci_dev *dev)
{
	struct xen_pcibk_config_quirk *quirk;
	int ret = 0;

	quirk = xen_pcibk_find_quirk(dev);
	if (!quirk) {
		ret = -ENXIO;
		goto out;
	}

	list_del(&quirk->quirks_list);
	kfree(quirk);

out:
	return ret;
}
ecb268e30242b1e&amp;id2=bed69721b67aeb3616e983ed32acc131968188f5'>root</a>/<a href='/cgit.cgi/linux/net-next.git/diff/include?id=56e3d92ddb97d9584622b29d4ecb268e30242b1e&amp;id2=bed69721b67aeb3616e983ed32acc131968188f5'>include</a>/<a href='/cgit.cgi/linux/net-next.git/diff/include/dt-bindings?id=56e3d92ddb97d9584622b29d4ecb268e30242b1e&amp;id2=bed69721b67aeb3616e983ed32acc131968188f5'>dt-bindings</a>/<a href='/cgit.cgi/linux/net-next.git/diff/include/dt-bindings/interrupt-controller?id=56e3d92ddb97d9584622b29d4ecb268e30242b1e&amp;id2=bed69721b67aeb3616e983ed32acc131968188f5'>interrupt-controller</a>/<a href='/cgit.cgi/linux/net-next.git/diff/include/dt-bindings/interrupt-controller/mips-gic.h?id=56e3d92ddb97d9584622b29d4ecb268e30242b1e&amp;id2=bed69721b67aeb3616e983ed32acc131968188f5'>mips-gic.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='56e3d92ddb97d9584622b29d4ecb268e30242b1e'/><input type='hidden' name='id2' value='bed69721b67aeb3616e983ed32acc131968188f5'/><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><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=56e3d92ddb97d9584622b29d4ecb268e30242b1e&amp;id2=bed69721b67aeb3616e983ed32acc131968188f5'>Diffstat</a> (limited to 'include/dt-bindings/interrupt-controller/mips-gic.h')</div><table summary='diffstat' class='diffstat'>f='/cgit.cgi/linux/net-next.git/tree/net/ipv4/tcp_lp.c?h=nds-private-remove&amp;id=966d2b04e070bc040319aaebfec09e0144dc3341'>net/ipv4/tcp_lp.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv4/tcp_lp.c?h=nds-private-remove&amp;id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/ipv4/tcp_lp.c?h=nds-private-remove&amp;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/?h=nds-private-remove&amp;id=966d2b04e070bc040319aaebfec09e0144dc3341'>Diffstat</a> (limited to 'net/ipv4/tcp_lp.c')</div><table summary='diffstat' class='diffstat'>