[PATCH 5.10 114/167] ALSA: pcm: Call substream ack() method upon compat mmap commit

[Greg Kroah-Hartman]

From: Alan Young <consult.awy@xxxxxxxxx>

commit 2e2832562c877e6530b8480982d99a4ff90c6777 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 sound/core/pcm_native.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3062,9 +3062,14 @@ static int snd_pcm_ioctl_sync_ptr_compat
 		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;