ALSA: line6: Clear prev_fbuf and prev_fsize properly

Clearing prev_fsize in line6_pcm_acquire() is pretty racy.
This can be called at any time while the stream is being played.
Rather better to clear prev_fbuf and prev_fsize at the proper place
like the stream stop for capture, and just after copying the monitor /
impulse data inside the spinlock.

Tested-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

2 files changed, 7 insertions, 7 deletions

diff --git a/sound/usb/line6/pcm.c b/sound/usb/line6/pcm.c
index f75825995e24..dedbe24cbf60 100644
--- a/sound/usb/line6/pcm.c
+++ b/sound/usb/line6/pcm.c
@@ -171,8 +171,6 @@ int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
 
         flags_final = 0;
 
-        line6pcm->prev_fbuf = NULL;
-
         if (test_flags(flags_old, flags_new, LINE6_BITS_CAPTURE_BUFFER)) {
                 err = line6_alloc_stream_buffer(line6pcm, &line6pcm->in);
                 if (err < 0)
@@ -193,7 +191,6 @@ int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
                 }
 
                 line6pcm->in.count = 0;
-                line6pcm->prev_fsize = 0;
                 err = line6_submit_audio_in_all_urbs(line6pcm);
 
                 if (err < 0)
@@ -248,8 +245,11 @@ int line6_pcm_release(struct snd_line6_pcm *line6pcm, int channels)
                 flags_new = flags_old & ~channels;
         } while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);
 
-        if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_STREAM))
+        if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_STREAM)) {
                 line6_unlink_audio_urbs(line6pcm, &line6pcm->in);
+                line6pcm->prev_fbuf = NULL;
+                line6pcm->prev_fsize = 0;
+        }
 
         if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_BUFFER)) {
                 line6_wait_clear_audio_urbs(line6pcm, &line6pcm->in);
diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c
index b4a26d0c8267..242265929145 100644
--- a/sound/usb/line6/playback.c
+++ b/sound/usb/line6/playback.c
@@ -166,9 +166,7 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm)
                 struct usb_iso_packet_descriptor *fout =
                     &urb_out->iso_frame_desc[i];
 
-                if (line6pcm->flags & LINE6_BITS_CAPTURE_STREAM)
-                        fsize = line6pcm->prev_fsize;
-
+                fsize = line6pcm->prev_fsize;
                 if (fsize == 0) {
                         int n;
 
@@ -263,6 +261,8 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm)
                                                    line6pcm->volume_monitor,
                                                    bytes_per_frame);
                 }
+                line6pcm->prev_fbuf = NULL;
+                line6pcm->prev_fsize = 0;
         }
         spin_unlock(&line6pcm->in.lock);