The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2e2832562c877e6530b8480982d99a4ff90c6777 Mon Sep 17 00:00:00 2001
From: Alan Young <consult.awy@xxxxxxxxx>
Date: Fri, 9 Jul 2021 09:48:54 +0100
Subject: [PATCH] ALSA: pcm: Call substream ack() method upon compat mmap
commit
If a 32-bit application is being used with a 64-bit kernel and is using
the mmap mechanism to write data, then the SNDRV_PCM_IOCTL_SYNC_PTR
ioctl results in calling snd_pcm_ioctl_sync_ptr_compat(). Make this use
pcm_lib_apply_appl_ptr() so that the substream's ack() method, if
defined, is called.
The snd_pcm_sync_ptr() function, used in the 64-bit ioctl case, already
uses snd_pcm_ioctl_sync_ptr_compat().
Fixes: 9027c4639ef1 ("ALSA: pcm: Call ack() whenever appl_ptr is updated")
Signed-off-by: Alan Young <consult.awy@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/c441f18c-eb2a-3bdd-299a-696ccca2de9c@xxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 14e32825c339..c88c4316c417 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3063,9 +3063,14 @@ static int snd_pcm_ioctl_sync_ptr_compat(struct snd_pcm_substream *substream,
boundary = 0x7fffffff;
snd_pcm_stream_lock_irq(substream);
/* FIXME: we should consider the boundary for the sync from app */
- if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
- control->appl_ptr = scontrol.appl_ptr;
- else
+ if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL)) {
+ err = pcm_lib_apply_appl_ptr(substream,
+ scontrol.appl_ptr);
+ if (err < 0) {
+ snd_pcm_stream_unlock_irq(substream);
+ return err;
+ }
+ } else
scontrol.appl_ptr = control->appl_ptr % boundary;
if (!(sflags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
control->avail_min = scontrol.avail_min;
