/*
* bebob_yamaha.c - a part of driver for BeBoB based devices
*
* Copyright (c) 2013-2014 Takashi Sakamoto
*
* Licensed under the terms of the GNU General Public License, version 2.
*/
#include "./bebob.h"
/*
* NOTE:
* Yamaha GO44 is not designed to be used as stand-alone mixer. So any streams
* must be accompanied. If changing the state, a LED on the device starts to
* blink and its sync status is false. In this state, the device sounds nothing
* even if streaming. To start streaming at the current sampling rate is only
* way to recover this state. GO46 is better for stand-alone mixer.
*
* Both of them have a capability to change its sampling rate up to 192.0kHz.
* At 192.0kHz, the device reports 4 PCM-in, 1 MIDI-in, 6 PCM-out, 1 MIDI-out.
* But Yamaha's driver reduce 2 PCM-in, 1 MIDI-in, 2 PCM-out, 1 MIDI-out to use
* 'Extended Stream Format Information Command - Single Request' in 'Additional
* AVC commands' defined by BridgeCo.
* This ALSA driver don't do this because a bit tiresome. Then isochronous
* streaming with many asynchronous transactions brings sounds with noises.
* Unfortunately current 'ffado-mixer' generated many asynchronous transaction
* to observe device's state, mainly check cmp connection and signal format. I
* recommend users to close ffado-mixer at 192.0kHz if mixer is needless.
*
* Terratec PHASE 24 FW and PHASE X24 FW are internally the same as
* Yamaha GO 44 and GO 46. Yamaha and Terratec had cooperated for these models.
*/
static enum snd_bebob_clock_type clk_src_types[] = {
SND_BEBOB_CLOCK_TYPE_INTERNAL,
SND_BEBOB_CLOCK_TYPE_EXTERNAL, /* S/PDIF */
};
static int
clk_src_get(struct snd_bebob *bebob, unsigned int *id)
{
int err;
err = avc_audio_get_selector(bebob->unit, 0, 4, id);
if (err < 0)
return err;
if (*id >= ARRAY_SIZE(clk_src_types))
return -EIO;
return 0;
}
static const struct snd_bebob_clock_spec clock_spec = {
.num = ARRAY_SIZE(clk_src_types),
.types = clk_src_types,
.get = &clk_src_get,
};
static const struct snd_bebob_rate_spec rate_spec = {
.get = &snd_bebob_stream_get_rate,
.set = &snd_bebob_stream_set_rate,
};
const struct snd_bebob_spec yamaha_terratec_spec = {
.clock = &clock_spec,
.rate = &rate_spec,
.meter = NULL
};
x/net-next.git/diff/include/dt-bindings/power/mt2701-power.h?h=nds-private-remove&id=3895dbf8985f656675b5bde610723a29cbce3fa7'>diff
|
mnt: Protect the mountpoint hashtable with mount_lock
Protecting the mountpoint hashtable with namespace_sem was sufficient
until a call to umount_mnt was added to mntput_no_expire. At which
point it became possible for multiple calls of put_mountpoint on
the same hash chain to happen on the same time.
Kristen Johansen <kjlx@templeofstupid.com> reported:
> This can cause a panic when simultaneous callers of put_mountpoint
> attempt to free the same mountpoint. This occurs because some callers
> hold the mount_hash_lock, while others hold the namespace lock. Some
> even hold both.
>
> In this submitter's case, the panic manifested itself as a GP fault in
> put_mountpoint() when it called hlist_del() and attempted to dereference
> a m_hash.pprev that had been poisioned by another thread.
Al Viro observed that the simple fix is to switch from using the namespace_sem
to the mount_lock to protect the mountpoint hash table.
I have taken Al's suggested patch moved put_mountpoint in pivot_root
(instead of taking mount_lock an additional time), and have replaced
new_mountpoint with get_mountpoint a function that does the hash table
lookup and addition under the mount_lock. The introduction of get_mounptoint
ensures that only the mount_lock is needed to manipulate the mountpoint
hashtable.
d_set_mounted is modified to only set DCACHE_MOUNTED if it is not
already set. This allows get_mountpoint to use the setting of
DCACHE_MOUNTED to ensure adding a struct mountpoint for a dentry
happens exactly once.
Cc: stable@vger.kernel.org
Fixes: ce07d891a089 ("mnt: Honor MNT_LOCKED when detaching mounts")
Reported-by: Krister Johansen <kjlx@templeofstupid.com>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>