linux.git/sound/core/timer.c, branch for-next

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43+00:00

no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")

To quote that commit,

  At -rc1 we'll need do a mechanical removal of no_llseek -

  git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\/d' $i
  done

  would do it.

Unfortunately, that hadn't been done.  Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
	.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro 
Signed-off-by: Linus Torvalds

ALSA: core: Drop superfluous no_free_ptr() for memdup_user() errors

2024-09-02T08:21:41+00:00

We used to wrap with no_free_ptr() for the return value from
memdup_user() with errors where the auto cleanup is applied.  This was
a workaround because the initial implementation of kfree auto-cleanup
checked only NULL pointers.

Since recently, though, the kfree auto-cleanup checks with
IS_ERR_OR_NULL() (by the commit cd7eb8f83fcf ("mm/slab: make
__free(kfree) accept error pointers")), hence those workarounds became
superfluous.  Let's drop them now.

Link: https://patch.msgid.link/20240902075246.3743-1-tiwai@suse.de
Signed-off-by: Takashi Iwai

ALSA: core: timer: Use NSEC_PER_SEC macro

2024-09-02T08:18:11+00:00

1000000000L is number of ns per second, use NSEC_PER_SEC macro to replace
it to make it more readable

Signed-off-by: Jinjie Ruan 
Link: https://patch.msgid.link/20240902071622.3519787-1-ruanjinjie@huawei.com
Signed-off-by: Takashi Iwai

ALSA: timer: Introduce virtual userspace-driven timers

2024-08-18T07:55:54+00:00

Implement two ioctl calls in order to support virtual userspace-driven
ALSA timers.

The first ioctl is SNDRV_TIMER_IOCTL_CREATE, which gets the
snd_timer_uinfo struct as a parameter and puts a file descriptor of a
virtual timer into the `fd` field of the snd_timer_unfo structure. It
also updates the `id` field of the snd_timer_uinfo struct, which
provides a unique identifier for the timer (basically, the subdevice
number which can be used when creating timer instances).

This patch also introduces a tiny id allocator for the userspace-driven
timers, which guarantees that we don't have more than 128 of them in the
system.

Another ioctl is SNDRV_TIMER_IOCTL_TRIGGER, which allows us to trigger
the virtual timer (and calls snd_timer_interrupt for the timer under
the hood), causing all of the timer instances binded to this timer to
execute their callbacks.

The maximum amount of ticks available for the timer is 1 for the sake of
simplicity of the userspace API. 'start', 'stop', 'open' and 'close'
callbacks for the userspace-driven timers are empty since we don't
really do any hardware initialization here.

Suggested-by: Axel Holzinger 
Signed-off-by: Ivan Orlov 
Signed-off-by: Takashi Iwai 
Link: https://patch.msgid.link/20240813120701.171743-4-ivan.orlov0322@gmail.com

ALSA: timer: Relax start tick time check for slave timer elements

2024-08-10T08:49:14+00:00

The recent addition of a sanity check for a too low start tick time
seems breaking some applications that uses aloop with a certain slave
timer setup.  They may have the initial resolution 0, hence it's
treated as if it were a too low value.

Relax and skip the check for the slave timer instance for addressing
the regression.

Fixes: 4a63bd179fa8 ("ALSA: timer: Set lower bound of start tick time")
Cc: 
Link: https://github.com/raspberrypi/linux/issues/6294
Link: https://patch.msgid.link/20240810084833.10939-1-tiwai@suse.de
Signed-off-by: Takashi Iwai

ALSA: timer: Set lower bound of start tick time

2024-05-16T14:00:08+00:00

Currently ALSA timer doesn't have the lower limit of the start tick
time, and it allows a very small size, e.g. 1 tick with 1ns resolution
for hrtimer.  Such a situation may lead to an unexpected RCU stall,
where  the callback repeatedly queuing the expire update, as reported
by fuzzer.

This patch introduces a sanity check of the timer start tick time, so
that the system returns an error when a too small start size is set.
As of this patch, the lower limit is hard-coded to 100us, which is
small enough but can still work somehow.

Reported-by: syzbot+43120c2af6ca2938cc38@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/000000000000fa00a1061740ab6d@google.com
Cc: 
Link: https://lore.kernel.org/r/20240514182745.4015-1-tiwai@suse.de
Signed-off-by: Takashi Iwai

ALSA: timer: Fix missing irq-disable at closing

2024-03-15T10:16:47+00:00

The conversion to guard macro dropped the irq-disablement at closing
mistakenly, which may lead to a race.  Fix it.

Fixes: beb45974dd49 ("ALSA: timer: Use guard() for locking")
Reported-by: syzbot+28c1a5a5b041a754b947@syzkaller.appspotmail.com
Closes: http://lore.kernel.org/r/0000000000000b9a510613b0145f@google.com
Message-ID: <20240315101447.18395-1-tiwai@suse.de>
Signed-off-by: Takashi Iwai

ALSA: timer: Use guard() for locking

2024-02-28T14:01:20+00:00

We can simplify the code gracefully with new guard() macro and co for
automatic cleanup of locks.

For making changes easier, some functions widen the application of
register_mutex, but those shouldn't influence on any actual
performance.

Also, one code block was factored out as a function so that guard()
can be applied cleanly without much indentation.

There are still a few remaining explicit spin_lock/unlock calls, and
those are for the places where we do temporary unlock/relock, which
doesn't fit well with the guard(), so far.

Only the code refactoring, and no functional changes.

Signed-off-by: Takashi Iwai 
Link: https://lore.kernel.org/r/20240227085306.9764-4-tiwai@suse.de

ALSA: timer: Use automatic cleanup of kfree()

2024-02-23T09:57:30+00:00

There are common patterns where a temporary buffer is allocated and
freed at the exit, and those can be simplified with the recent cleanup
mechanism via __free(kfree).

No functional changes, only code refactoring.

Signed-off-by: Takashi Iwai 
Link: https://lore.kernel.org/r/20240222111509.28390-5-tiwai@suse.de

ALSA: timer: Create device with snd_device_alloc()

2023-08-17T07:24:21+00:00

Align with the other components, and use snd_device_alloc() for the
new sound device for timer, too.  No functional changes.

Reviewed-by: Jaroslav Kysela 
Signed-off-by: Curtis Malainey 
Tested-by: Curtis Malainey 
Link: https://lore.kernel.org/r/20230816160252.23396-8-tiwai@suse.de
Signed-off-by: Takashi Iwai