/*
 * ALSA SoC SPDIF DIT driver
 *
 *  This driver is used by controllers which can operate in DIT (SPDI/F) where
 *  no codec is needed.  This file provides stub codec that can be used
 *  in these configurations. TI DaVinci Audio controller uses this driver.
 *
 * Author:      Steve Chen,  <schen@mvista.com>
 * Copyright:   (C) 2009 MontaVista Software, Inc., <source@mvista.com>
 * Copyright:   (C) 2009  Texas Instruments, India
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <sound/soc.h>
#include <sound/pcm.h>
#include <sound/initval.h>
#include <linux/of.h>

#define DRV_NAME "spdif-dit"

#define STUB_RATES	SNDRV_PCM_RATE_8000_192000
#define STUB_FORMATS	(SNDRV_PCM_FMTBIT_S16_LE | \
			SNDRV_PCM_FMTBIT_S20_3LE | \
			SNDRV_PCM_FMTBIT_S24_LE)

static const struct snd_soc_dapm_widget dit_widgets[] = {
	SND_SOC_DAPM_OUTPUT("spdif-out"),
};

static const struct snd_soc_dapm_route dit_routes[] = {
	{ "spdif-out", NULL, "Playback" },
};

static struct snd_soc_codec_driver soc_codec_spdif_dit = {
	.component_driver = {
		.dapm_widgets		= dit_widgets,
		.num_dapm_widgets	= ARRAY_SIZE(dit_widgets),
		.dapm_routes		= dit_routes,
		.num_dapm_routes	= ARRAY_SIZE(dit_routes),
	},
};

static struct snd_soc_dai_driver dit_stub_dai = {
	.name		= "dit-hifi",
	.playback 	= {
		.stream_name	= "Playback",
		.channels_min	= 1,
		.channels_max	= 384,
		.rates		= STUB_RATES,
		.formats	= STUB_FORMATS,
	},
};

static int spdif_dit_probe(struct platform_device *pdev)
{
	return snd_soc_register_codec(&pdev->dev, &soc_codec_spdif_dit,
			&dit_stub_dai, 1);
}

static int spdif_dit_remove(struct platform_device *pdev)
{
	snd_soc_unregister_codec(&pdev->dev);
	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id spdif_dit_dt_ids[] = {
	{ .compatible = "linux,spdif-dit", },
	{ }
};
MODULE_DEVICE_TABLE(of, spdif_dit_dt_ids);
#endif

static struct platform_driver spdif_dit_driver = {
	.probe		= spdif_dit_probe,
	.remove		= spdif_dit_remove,
	.driver		= {
		.name	= DRV_NAME,
		.of_match_table = of_match_ptr(spdif_dit_dt_ids),
	},
};

module_platform_driver(spdif_dit_driver);

MODULE_AUTHOR("Steve Chen <schen@mvista.com>");
MODULE_DESCRIPTION("SPDIF dummy codec driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
ut class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/?id=69973b830859bc6529a7a0468ba0d80ee5117826'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/include?id=69973b830859bc6529a7a0468ba0d80ee5117826'>include</a>/<a href='/cgit.cgi/linux/net-next.git/log/include/trace?id=69973b830859bc6529a7a0468ba0d80ee5117826'>trace</a>/<a href='/cgit.cgi/linux/net-next.git/log/include/trace/events?id=69973b830859bc6529a7a0468ba0d80ee5117826'>events</a>/<a href='/cgit.cgi/linux/net-next.git/log/include/trace/events/ipi.h?id=69973b830859bc6529a7a0468ba0d80ee5117826'>ipi.h</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/include/trace/events/ipi.h?id=69973b830859bc6529a7a0468ba0d80ee5117826&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
='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/net/sched/sch_generic.c?id=966d2b04e070bc040319aaebfec09e0144dc3341'>966d2b04e070bc040319aaebfec09e0144dc3341</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/sched/sch_generic.c?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/net/sched/sch_generic.c?id=966d2b04e070bc040319aaebfec09e0144dc3341'>net/sched/sch_generic.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/sched/sch_generic.c?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/sched/sch_generic.c?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 'net/sched/sch_generic.c')</div><table summary='diffstat' class='diffstat'>