/*
 *  PCM DRM helpers
 *
 *   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/export.h>
#include <linux/types.h>
#include <sound/asoundef.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/pcm_iec958.h>

static int create_iec958_consumer(uint rate, uint sample_width,
				  u8 *cs, size_t len)
{
	unsigned int fs, ws;

	if (len < 4)
		return -EINVAL;

	switch (rate) {
	case 32000:
		fs = IEC958_AES3_CON_FS_32000;
		break;
	case 44100:
		fs = IEC958_AES3_CON_FS_44100;
		break;
	case 48000:
		fs = IEC958_AES3_CON_FS_48000;
		break;
	case 88200:
		fs = IEC958_AES3_CON_FS_88200;
		break;
	case 96000:
		fs = IEC958_AES3_CON_FS_96000;
		break;
	case 176400:
		fs = IEC958_AES3_CON_FS_176400;
		break;
	case 192000:
		fs = IEC958_AES3_CON_FS_192000;
		break;
	default:
		return -EINVAL;
	}

	if (len > 4) {
		switch (sample_width) {
		case 16:
			ws = IEC958_AES4_CON_WORDLEN_20_16;
			break;
		case 18:
			ws = IEC958_AES4_CON_WORDLEN_22_18;
			break;
		case 20:
			ws = IEC958_AES4_CON_WORDLEN_20_16 |
			     IEC958_AES4_CON_MAX_WORDLEN_24;
			break;
		case 24:
		case 32: /* Assume 24-bit width for 32-bit samples. */
			ws = IEC958_AES4_CON_WORDLEN_24_20 |
			     IEC958_AES4_CON_MAX_WORDLEN_24;
			break;

		default:
			return -EINVAL;
		}
	}

	memset(cs, 0, len);

	cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
	cs[1] = IEC958_AES1_CON_GENERAL;
	cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
	cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs;

	if (len > 4)
		cs[4] = ws;

	return len;
}

/**
 * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
 * @runtime: pcm runtime structure with ->rate filled in
 * @cs: channel status buffer, at least four bytes
 * @len: length of channel status buffer
 *
 * Create the consumer format channel status data in @cs of maximum size
 * @len corresponding to the parameters of the PCM runtime @runtime.
 *
 * Drivers may wish to tweak the contents of the buffer after creation.
 *
 * Returns: length of buffer, or negative error code if something failed.
 */
int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
	size_t len)
{
	return create_iec958_consumer(runtime->rate,
				      snd_pcm_format_width(runtime->format),
				      cs, len);
}
EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);

/**
 * snd_pcm_create_iec958_consumer_hw_params - create IEC958 channel status
 * @hw_params: the hw_params instance for extracting rate and sample format
 * @cs: channel status buffer, at least four bytes
 * @len: length of channel status buffer
 *
 * Create the consumer format channel status data in @cs of maximum size
 * @len corresponding to the parameters of the PCM runtime @runtime.
 *
 * Drivers may wish to tweak the contents of the buffer after creation.
 *
 * Returns: length of buffer, or negative error code if something failed.
 */
int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params,
					     u8 *cs, size_t len)
{
	return create_iec958_consumer(params_rate(params), params_width(params),
				      cs, len);
}
EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params);
 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/sound/pcmcia/pdaudiocf/pdaudiocf_pcm.c?id=2ef0359031b9ed891ca381b2687186fb52b277f8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
e='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/sound/usb?id=966d2b04e070bc040319aaebfec09e0144dc3341'>966d2b04e070bc040319aaebfec09e0144dc3341</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/usb?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/sound/usb?id=966d2b04e070bc040319aaebfec09e0144dc3341'>sound/usb</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/usb?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/usb?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 'sound/usb')</div><table summary='diffstat' class='diffstat'>