| Message ID | 20170524010430.1371-1-o-takashi@sakamocchi.jp (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 24 May 2017 03:04:30 +0200, Takashi Sakamoto wrote: > > In current implementation of ALSA control core, list operation has > a limitation to handle 16384 entries at once. This seems due to > allocation in kernel space to copy data from user space. > > With a commit 53e7bf452584 ("ALSA: control: Simplify snd_ctl_elem_list() > implementation"), for the operation, ALSA control core copies data > into user space directly. No need to care of kernel spaces anymore. > > This commit purges the limitation. > --- You forgot your sign-off. thanks, Takashi
On 2017年05月24日 15:31, Takashi Iwai wrote: > On Wed, 24 May 2017 03:04:30 +0200, > Takashi Sakamoto wrote: >> >> In current implementation of ALSA control core, list operation has >> a limitation to handle 16384 entries at once. This seems due to >> allocation in kernel space to copy data from user space. >> >> With a commit 53e7bf452584 ("ALSA: control: Simplify snd_ctl_elem_list() >> implementation"), for the operation, ALSA control core copies data >> into user space directly. No need to care of kernel spaces anymore. >> >> This commit purges the limitation. >> --- > > You forgot your sign-off. Oops. I might be tired in this morning... Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Thanks Takashi Sakamoto
On Wed, 24 May 2017 10:16:47 +0200, Takashi Sakamoto wrote: > > On 2017年05月24日 15:31, Takashi Iwai wrote: > > On Wed, 24 May 2017 03:04:30 +0200, > > Takashi Sakamoto wrote: > >> > >> In current implementation of ALSA control core, list operation has > >> a limitation to handle 16384 entries at once. This seems due to > >> allocation in kernel space to copy data from user space. > >> > >> With a commit 53e7bf452584 ("ALSA: control: Simplify snd_ctl_elem_list() > >> implementation"), for the operation, ALSA control core copies data > >> into user space directly. No need to care of kernel spaces anymore. > >> > >> This commit purges the limitation. > >> --- > > > > You forgot your sign-off. > > Oops. I might be tired in this morning... > > Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Applied now. Thanks. Takashi
diff --git a/sound/core/control.c b/sound/core/control.c index 47080da8451a..ecd358213b83 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -757,9 +757,7 @@ static int snd_ctl_elem_list(struct snd_card *card, return -EFAULT; offset = list.offset; space = list.space; - /* try limit maximum space */ - if (space > 16384) - return -ENOMEM; + down_read(&card->controls_rwsem); list.count = card->controls_count; list.used = 0;
In current implementation of ALSA control core, list operation has a limitation to handle 16384 entries at once. This seems due to allocation in kernel space to copy data from user space. With a commit 53e7bf452584 ("ALSA: control: Simplify snd_ctl_elem_list() implementation"), for the operation, ALSA control core copies data into user space directly. No need to care of kernel spaces anymore. This commit purges the limitation. --- sound/core/control.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)