/*
 *  Copyright (c) by Lee Revell <rlrevell@joe-job.com>
 *                   Clemens Ladisch <clemens@ladisch.de>
 *  Routines for control of EMU10K1 chips
 *
 *  BUGS:
 *    --
 *
 *  TODO:
 *    --
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/time.h>
#include <sound/core.h>
#include <sound/emu10k1.h>

static int snd_emu10k1_timer_start(struct snd_timer *timer)
{
	struct snd_emu10k1 *emu;
	unsigned long flags;
	unsigned int delay;

	emu = snd_timer_chip(timer);
	delay = timer->sticks - 1;
	if (delay < 5 ) /* minimum time is 5 ticks */
		delay = 5;
	spin_lock_irqsave(&emu->reg_lock, flags);
	snd_emu10k1_intr_enable(emu, INTE_INTERVALTIMERENB);
	outw(delay & TIMER_RATE_MASK, emu->port + TIMER);
	spin_unlock_irqrestore(&emu->reg_lock, flags);
	return 0;
}

static int snd_emu10k1_timer_stop(struct snd_timer *timer)
{
	struct snd_emu10k1 *emu;
	unsigned long flags;

	emu = snd_timer_chip(timer);
	spin_lock_irqsave(&emu->reg_lock, flags);
	snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB);
	spin_unlock_irqrestore(&emu->reg_lock, flags);
	return 0;
}

static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer,
					       unsigned long *num, unsigned long *den)
{
	*num = 1;
	*den = 48000;
	return 0;
}

static struct snd_timer_hardware snd_emu10k1_timer_hw = {
	.flags = SNDRV_TIMER_HW_AUTO,
	.resolution = 20833, /* 1 sample @ 48KHZ = 20.833...us */
	.ticks = 1024,
	.start = snd_emu10k1_timer_start,
	.stop = snd_emu10k1_timer_stop,
	.precise_resolution = snd_emu10k1_timer_precise_resolution,
};

int snd_emu10k1_timer(struct snd_emu10k1 *emu, int device)
{
	struct snd_timer *timer = NULL;
	struct snd_timer_id tid;
	int err;

	tid.dev_class = SNDRV_TIMER_CLASS_CARD;
	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
	tid.card = emu->card->number;
	tid.device = device;
	tid.subdevice = 0;
	if ((err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer)) >= 0) {
		strcpy(timer->name, "EMU10K1 timer");
		timer->private_data = emu;
		timer->hw = snd_emu10k1_timer_hw;
	}
	emu->timer = timer;
	return err;
}
>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/mac80211?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>mac80211</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/mac80211/fils_aead.c?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>fils_aead.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='91539eb1fda2d530d3b268eef542c5414e54bf1a'/><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>Iago Abal &lt;mail@iagoabal.eu&gt;</td><td class='right'>2017-01-11 14:00:21 +0100</td></tr>
<tr><th>committer</th><td>Vinod Koul &lt;vinod.koul@intel.com&gt;</td><td class='right'>2017-01-25 15:35:11 +0530</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/mac80211/fils_aead.c?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>91539eb1fda2d530d3b268eef542c5414e54bf1a</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/mac80211/fils_aead.c?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>960f5ca6342ad20837aff18aad6e8ecd7da32fd6</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/mac80211/fils_aead.c?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>net/mac80211/fils_aead.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/mac80211/fils_aead.c?id=6610d0edf6dc7ee97e46ab3a538a565c79d26199'>6610d0edf6dc7ee97e46ab3a538a565c79d26199</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/mac80211/fils_aead.c?id=91539eb1fda2d530d3b268eef542c5414e54bf1a&amp;id2=6610d0edf6dc7ee97e46ab3a538a565c79d26199'>diff</a>)</td></tr></table>
<div class='commit-subject'>dmaengine: pl330: fix double lock</div><div class='commit-msg'>The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the
following double-lock bug:

    Double lock:
    1. spin_lock_irqsave(pch-&gt;lock, flags) at pl330_free_chan_resources:2236;
    2. call to function `pl330_release_channel' immediately after;
    3. call to function `dma_pl330_rqcb' in line 1753;
    4. spin_lock_irqsave(pch-&gt;lock, flags) at dma_pl330_rqcb:1505.

I have fixed it as suggested by Marek Szyprowski.

First, I have replaced `pch-&gt;lock' with `pl330-&gt;lock' in functions
`pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids
the double-lock by acquiring a different lock than `dma_pl330_rqcb'.

NOTE that, as a result, `pl330_free_chan_resources' executes
`list_splice_tail_init' on `pch-&gt;work_list' under lock `pl330-&gt;lock',
whereas in the rest of the code `pch-&gt;work_list' is protected by
`pch-&gt;lock'. I don't know if this may cause race conditions. Similarly
`pch-&gt;cyclic' is written by `pl330_alloc_chan_resources' under
`pl330-&gt;lock' but read by `pl330_tx_submit' under `pch-&gt;lock'.

Second, I have removed locking from `pl330_request_channel' and
`pl330_release_channel' functions. Function `pl330_request_channel' is
only called from `pl330_alloc_chan_resources', so the lock is already
held. Function `pl330_release_channel' is called from
`pl330_free_chan_resources', which already holds the lock, and from
`pl330_del'. Function `pl330_del' is called in an error path of
`pl330_probe' and at the end of `pl330_remove', but I assume that there
cannot be concurrent accesses to the protected data at those points.

Signed-off-by: Iago Abal &lt;mail@iagoabal.eu&gt;
Reviewed-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Signed-off-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>Diffstat</a> (limited to 'net/mac80211/fils_aead.c')</div><table summary='diffstat' class='diffstat'>