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ALSA: pcm: Convert snd_pcm_sync_ptr() to user_access_begin/user_access_end()

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Now that snd_pcm_sync_ptr_get_user() and snd_pcm_sync_ptr_put_user()
are converted to user_access_begin/user_access_end(),
snd_pcm_sync_ptr_get_user() is more efficient than a raw get_user()
followed by a copy_from_user(). And because copy_{to/from}_user() are
generic functions focussed on transfer of big data blocks to/from user,
snd_pcm_sync_ptr_put_user() is also more efficient for small amont of
data.

So use snd_pcm_sync_ptr_get_user() and snd_pcm_sync_ptr_put_user() in
snd_pcm_sync_ptr() too.

snd_pcm_ioctl_sync_ptr_buggy() is left as it is because the conversion
wouldn't be straigh-forward due to the workaround it provides.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/6ce6bc4da498ea7ea2be5f279b374370b1613b13.1749883041.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2025-06-14 08:43:17 +02:00 committed by Takashi Iwai
parent c72fad73ba
commit 8629eea901
1 changed files with 18 additions and 20 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

38
sound/core/pcm_native.c
View file

@ -3096,45 +3096,43 @@ static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
struct snd_pcm_sync_ptr __user *_sync_ptr) struct snd_pcm_sync_ptr __user *_sync_ptr)
{ {
struct snd_pcm_runtime *runtime = substream->runtime; struct snd_pcm_runtime *runtime = substream->runtime;
struct snd_pcm_sync_ptr sync_ptr;
volatile struct snd_pcm_mmap_status *status; volatile struct snd_pcm_mmap_status *status;
volatile struct snd_pcm_mmap_control *control; volatile struct snd_pcm_mmap_control *control;
u32 sflags;
struct snd_pcm_mmap_control scontrol;
struct snd_pcm_mmap_status sstatus;
int err; int err;
memset(&sync_ptr, 0, sizeof(sync_ptr)); if (snd_pcm_sync_ptr_get_user(sflags, scontrol, _sync_ptr))
if (get_user(sync_ptr.flags, (unsigned __user *)&(_sync_ptr->flags)))
return -EFAULT; return -EFAULT;
if (copy_from_user(&sync_ptr.c.control, &(_sync_ptr->c.control), sizeof(struct snd_pcm_mmap_control)))
return -EFAULT;
status = runtime->status; status = runtime->status;
control = runtime->control; control = runtime->control;
if (sync_ptr.flags & SNDRV_PCM_SYNC_PTR_HWSYNC) { if (sflags & SNDRV_PCM_SYNC_PTR_HWSYNC) {
err = snd_pcm_hwsync(substream); err = snd_pcm_hwsync(substream);
if (err < 0) if (err < 0)
return err; return err;
} }
scoped_guard(pcm_stream_lock_irq, substream) { scoped_guard(pcm_stream_lock_irq, substream) {
if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) { if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL)) {
err = pcm_lib_apply_appl_ptr(substream, err = pcm_lib_apply_appl_ptr(substream, scontrol.appl_ptr);
sync_ptr.c.control.appl_ptr);
if (err < 0) if (err < 0)
return err; return err;
} else { } else {
sync_ptr.c.control.appl_ptr = control->appl_ptr; scontrol.appl_ptr = control->appl_ptr;
} }
if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN)) if (!(sflags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
control->avail_min = sync_ptr.c.control.avail_min; control->avail_min = scontrol.avail_min;
else else
sync_ptr.c.control.avail_min = control->avail_min; scontrol.avail_min = control->avail_min;
sync_ptr.s.status.state = status->state; sstatus.state = status->state;
sync_ptr.s.status.hw_ptr = status->hw_ptr; sstatus.hw_ptr = status->hw_ptr;
sync_ptr.s.status.tstamp = status->tstamp; sstatus.tstamp = status->tstamp;
sync_ptr.s.status.suspended_state = status->suspended_state; sstatus.suspended_state = status->suspended_state;
sync_ptr.s.status.audio_tstamp = status->audio_tstamp; sstatus.audio_tstamp = status->audio_tstamp;
} }
if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE); snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
if (copy_to_user(_sync_ptr, &sync_ptr, sizeof(sync_ptr))) if (snd_pcm_sync_ptr_put_user(sstatus, scontrol, _sync_ptr))
return -EFAULT; return -EFAULT;
return 0; return 0;
} }