At present, trace events are probed even if corresponding parameter is
not actually changed. This is inconvenient.
This commit improves the behaviour.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
When refining mask/interval parameters, helper functions can return error
code. This error is not handled immediately. This seems to return
parameters to userspace applications in its meddle of processing.
However, in general, when receiving error from system calls, the
application might not handle argument buffer. It's reasonable to
judge the above design as superfluity.
This commit handles the error immediately.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Use the same print format of snd_pcm_debug_name() for userspace tracing
program.
Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Results of ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE and
SNDRV_PCM_IOCTL_HW_PARAMS are different, because the latter has single
value for several parameters; e.g. channels of PCM substream. Selection
of the single value is done independently of application of constraints.
It's helpful for developers to trace the selection process.
This commit adds tracepoints to snd_pcm_hw_params_choose() for the
purpose.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
As of v4.12, snd_pcm_hw_params_choose() is just called in a process
context of ioctl(2) with SNDRV_PCM_IOCTL_HW_PARAMS. The function locates
in a different file, which has no tracepoints.
This commit moves the function to a file with the tracepoints for later
commit.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
When drivers register no flags about information of PCM hardware, ALSA
PCM core fixups it roughly. Currently, this operation places in a
function snd_pcm_hw_refine(). It can be moved to a function
fixup_unreferenced_params() because it doesn't affects operations
between these two functions.
This idea is better to bundle codes with similar purposes and this commit
achieves it.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A structure for parameters of PCM runtime has parameters which are
not classified as mask/interval type. They are decided only when
corresponding normal parameters have unique values.
* struct snd_pcm_hw_params.msbits
* struct snd_pcm_hw_params.rate_num
* struct snd_pcm_hw_params.rate_den
* struct snd_pcm_hw_params.fifo_size
Current implementation of hw_params ioctl sometimes doesn't decide these
parameters even if corresponding parameters are fixed, because these
parameters are evaluated before a call of snd_pcm_hw_params_choose().
This commit adds a helper function to process the parameters and call it
in proper positions.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
To fixup some parameters, ALSA PCM core refers the other parameters as
constants. There're some macros for this purpose.
This commit replaces codes with them.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Drivers add rules of parameters to runtime of PCM substream, when
applications open ALSA PCM character device. When applications call
ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE or SNDRV_PCM_IOCTL_HW_PARAMS, the
rules are applied to the parameters and return the result to user space.
The rule can have dependency between parameters. Additionally, it can have
condition flags about application of rules. Userspace applications can
indicate the flags to suppress change of parameters.
This commit attempts to describe the mechanism.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A commit 8bea869c5e ("ALSA: PCM midlevel: improve fifo_size handling")
allows drivers to implement calculation of fifo size in parameter
structure. This calculation runs only when two of the other parameters
have single value.
In ALSA PCM core, there're some helper functions for the case. This commit
applies the functions instead of value comparison.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit modifies current for readability in below aspects:
- use bool type variable instead of int type variable assigned to 0/1
- move variable definition from loop to top of the function definition
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A local variable is used to judge whether a parameter should be handled
due to reverse dependency of the other rules. However, this can be
obsoleted by check of a sentinel in dependency array.
This commit removes the local variable and check the sentinel to reduce
stack usage.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In a process to calculate parameters of PCM substream, application of all
rules is iterated several times till parameter dependencies are satisfied.
In current implementation, two loops are used for the design, however this
brings two-level indentation and decline readability.
This commit attempts to reduce the indentation by using goto statement,
instead of outer while loop.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Application of rules to parameters of PCM substream is done in a call of
snd_pcm_hw_refine(), while the function includes much codes and is not
enough friendly to readers.
This commit splits the codes to a separated function so that readers can
get it easily. I leave desicion into compilers to merge the function into
its callee.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Application of constraints to interval-type parameters for PCM substream
is done in a call of snd_pcm_hw_refine(), while the function includes
much codes and is not enough friendly to readers.
This commit splits the codes to a separated function so that readers can
get it easily. I leave desicion into compilers to merge the function into
its callee.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Application of constraints to mask-type parameters for PCM substream is
done in a call of snd_pcm_hw_refine(), while the function includes much
codes and is not enough friendly to readers.
This commit splits the codes to a separated function so that readers can
get it easily. I leave desicion into compilers to merge the function into
its callee.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In a previous commit, tracepoints are added for PCM parameter processing.
As long as I know, this implementation increases size of relocatable
object by 35%. For vendors who are conscious of memory footprint, it
brings apparent disadvantage.
This commit utilizes CONFIG_SND_DEBUG configuration to enable/disable the
tracepoints.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
When working for devices which support configurable modes for its data
transmission or which consists of several components, developers are
likely to use rules of parameters of PCM substream. However, there's no
infrastructure to assist their work.
In old days, ALSA PCM core got a local 'RULES_DEBUG' macro to debug
refinement of parameters for PCM substream. Although this is merely a
makeshift. With some modifications, we get the infrastructure.
This commit is for the purpose. Refinement of mask/interval type of
PCM parameters is probed as tracepoint events as 'hw_mask_param' and
'hw_interval_param' on existent 'snd_pcm' subsystem.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
For accessing the snd_timer_user queue indices, we take tu->qlock.
But it's forgotten in a couple of places.
The one in snd_timer_user_params() should be safe without the
spinlock as the timer is already stopped. But it's better for
consistency.
The one in poll is just a read-out, so it's not inevitably needed, but
it'd be good to make the result consistent, too.
Tested-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
ALSA timer may reallocate the user queue upon request, and it happens
at three places for now: at opening, at SNDRV_TIMER_IOCTL_PARAMS, and
at SNDRV_TIMER_IOCTL_SELECT. However, the last one,
snd_timer_user_tselect(), doesn't need to reallocate the buffer since
it doesn't change the queue size. It does just because tu->tread
might have been changed before starting the timer.
Instead of *_SELECT ioctl, we should reallocate the queue at
SNDRV_TIMER_IOCTL_TREAD; then the timer is guaranteed to be stopped,
thus we can reassign the buffer more safely.
This patch implements that with a slight code refactoring.
Essentially, the patch achieves:
- Introduce realloc_user_queue() for (re-)allocating the ring buffer,
and call it from all places. Also, realloc_user_queue() uses
kcalloc() for avoiding possible leaks.
- Add the buffer reallocation at SNDRV_TIMER_IOCTL_TREAD. When it
fails, tu->tread is restored to the old value, too.
- Drop the buffer reallocation at snd_timer_user_tselect().
Tested-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
snd_timer_user_tselect() reallocates the queue buffer dynamically, but
it forgot to reset its indices. Since the read may happen
concurrently with ioctl and snd_timer_user_tselect() allocates the
buffer via kmalloc(), this may lead to the leak of uninitialized
kernel-space data, as spotted via KMSAN:
BUG: KMSAN: use of unitialized memory in snd_timer_user_read+0x6c4/0xa10
CPU: 0 PID: 1037 Comm: probe Not tainted 4.11.0-rc5+ #2739
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:16
dump_stack+0x143/0x1b0 lib/dump_stack.c:52
kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:1007
kmsan_check_memory+0xc2/0x140 mm/kmsan/kmsan.c:1086
copy_to_user ./arch/x86/include/asm/uaccess.h:725
snd_timer_user_read+0x6c4/0xa10 sound/core/timer.c:2004
do_loop_readv_writev fs/read_write.c:716
__do_readv_writev+0x94c/0x1380 fs/read_write.c:864
do_readv_writev fs/read_write.c:894
vfs_readv fs/read_write.c:908
do_readv+0x52a/0x5d0 fs/read_write.c:934
SYSC_readv+0xb6/0xd0 fs/read_write.c:1021
SyS_readv+0x87/0xb0 fs/read_write.c:1018
This patch adds the missing reset of queue indices. Together with the
previous fix for the ioctl/read race, we cover the whole problem.
Reported-by: Alexander Potapenko <glider@google.com>
Tested-by: Alexander Potapenko <glider@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The read from ALSA timer device, the function snd_timer_user_tread(),
may access to an uninitialized struct snd_timer_user fields when the
read is concurrently performed while the ioctl like
snd_timer_user_tselect() is invoked. We have already fixed the races
among ioctls via a mutex, but we seem to have forgotten the race
between read vs ioctl.
This patch simply applies (more exactly extends the already applied
range of) tu->ioctl_lock in snd_timer_user_tread() for closing the
race window.
Reported-by: Alexander Potapenko <glider@google.com>
Tested-by: Alexander Potapenko <glider@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The snd_pcm_oss_writev3() and snd_pcm_oss_readv3() are used only in
io.c with CONFIG_SND_PCM_OSS_PLUGINS=y. Add an ifdef to reduce the
build of these functions.
Along with it, since they are called always for in-kernel copy, reduce
the argument and call snd_pcm_kernel_writev() and *_readv() directly
instead.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Takashi Sakamoto
Takashi Iwai