ALSA: line6: Fix the error recovery in line6_pcm_acquire()

line6_pcm_acquire() tries to restore the newly obtained resources at
the error path.  But some flags aren't recorded and released properly
when the corresponding buffer is already present.  These bits have to
be cleared in the error recovery, too.

Also, "flags_final" can be initialized to zero since we pass only the
subset of "channels" bits.

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

diff --git a/sound/usb/line6/pcm.c b/sound/usb/line6/pcm.c
index f740b4490d75798fc89077801e37730746fa3605..9a2a15f4c4e42a38ea96062711c97659b0844a7b 100644 (file)
--- a/sound/usb/line6/pcm.c
+++ b/sound/usb/line6/pcm.c
@@ -106,7 +106,7 @@ int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
                flags_new = flags_old | channels;
        } while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);
 
-       flags_final = flags_old;
+       flags_final = 0;
 
        line6pcm->prev_fbuf = NULL;
 
@@ -120,9 +120,9 @@ int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
                                err = -ENOMEM;
                                goto pcm_acquire_error;
                        }
-
-                       flags_final |= channels & LINE6_BITS_CAPTURE_BUFFER;
                }
+
+               flags_final |= channels & LINE6_BITS_CAPTURE_BUFFER;
        }
 
        if (test_flags(flags_old, flags_new, LINE6_BITS_CAPTURE_STREAM)) {
@@ -157,9 +157,9 @@ int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
                                err = -ENOMEM;
                                goto pcm_acquire_error;
                        }
-
-                       flags_final |= channels & LINE6_BITS_PLAYBACK_BUFFER;
                }
+
+               flags_final |= channels & LINE6_BITS_PLAYBACK_BUFFER;
        }
 
        if (test_flags(flags_old, flags_new, LINE6_BITS_PLAYBACK_STREAM)) {
@@ -187,7 +187,7 @@ pcm_acquire_error:
           If not all requested resources/streams could be obtained, release
           those which were successfully obtained (if any).
        */
-       line6_pcm_release(line6pcm, flags_final & channels);
+       line6_pcm_release(line6pcm, flags_final);
        return err;
 }
 EXPORT_SYMBOL_GPL(line6_pcm_acquire);