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: NChris Rorvick <chris@rorvick.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

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 @@ int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
 	   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);