ALSA: firewire-lib: taskletize the snd_pcm_period_elapsed() call

The following patch might introduce this call chain:
  PCM .pointer callback
  + fw_iso_context_flush_completions
    + packet callback
      + snd_pcm_period_elapsed
        + PCM .pointer callback
Recursive calls to the pointer callback are not possible due to the PCM
group locking, so avoid this by moving the period notification into
a separate tasklet.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 3 insertions, 12 deletions

diff --git a/sound/firewire/amdtp.h b/sound/firewire/amdtp.h
index 537a9cb83581..4987f826f9f3 100644
--- a/sound/firewire/amdtp.h
+++ b/sound/firewire/amdtp.h
@@ -1,6 +1,7 @@
 #ifndef SOUND_FIREWIRE_AMDTP_H_INCLUDED
 #define SOUND_FIREWIRE_AMDTP_H_INCLUDED
 
+#include <linux/interrupt.h>
 #include <linux/mutex.h>
 #include <linux/spinlock.h>
 #include "packets-buffer.h"
@@ -55,6 +56,7 @@ struct amdtp_out_stream {
         struct iso_packets_buffer buffer;
 
         struct snd_pcm_substream *pcm;
+        struct tasklet_struct period_tasklet;
 
         int packet_index;
         unsigned int data_block_counter;
@@ -81,6 +83,7 @@ void amdtp_out_stream_stop(struct amdtp_out_stream *s);
 
 void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
                                      snd_pcm_format_t format);
+void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s);
 void amdtp_out_stream_pcm_abort(struct amdtp_out_stream *s);
 
 /**
@@ -123,18 +126,6 @@ static inline bool amdtp_out_streaming_error(struct amdtp_out_stream *s)
 }
 
 /**
- * amdtp_out_stream_pcm_prepare - prepare PCM device for running
- * @s: the AMDTP output stream
- *
- * This function should be called from the PCM device's .prepare callback.
- */
-static inline void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s)
-{
-        s->pcm_buffer_pointer = 0;
-        s->pcm_period_pointer = 0;
-}
-
-/**
  * amdtp_out_stream_pcm_trigger - start/stop playback from a PCM device
  * @s: the AMDTP output stream
  * @pcm: the PCM device to be started, or %NULL to stop the current device