Merge tag 'firewire-updates-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394

Pull firewire updates from Takashi Sakamoto:
 "In the FireWire subsystem, tasklets have been used as the bottom half
  of 1394 OHCi hardIRQ. In recent kernel updates, BH workqueues have
  become available, and some developers have proposed replacing the
  tasklet with a BH workqueue.

  As a first step towards dropping tasklet use, the 1394 OHCI
  isochronous context can use regular workqueues. In this context, the
  batch of packets is processed in the specific queue, thus the timing
  jitter caused by task scheduling is not so critical.

  Additionally, DMA transmission can be scheduled per-packet basis,
  therefore the context can be sleep between the operation of
  transmissions. Furthermore, in-kernel protocol implementation involves
  some CPU-bound tasks, which can sometimes consumes CPU time so long.
  These characteristics suggest that normal workqueues are suitable,
  through BH workqueues are not.

  The replacement with a workqueue allows unit drivers to process the
  content of packets in non-atomic context. It brings some reliefs to
  some drivers in sound subsystem that spin-lock is not mandatory
  anymore during isochronous packet processing.

  Summary:

   - Replace tasklet with workqueue for isochronous context

   - Replace IDR with XArray

   - Utilize guard macro where possible

   - Print deprecation warning when enabling debug parameter of
     firewire-ohci module

   - Switch to nonatomic PCM operation"

* tag 'firewire-updates-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394: (55 commits)
  firewire: core: rename cause flag of tracepoints event
  firewire: core: update documentation of kernel APIs for flushing completions
  firewire: core: add helper function to retire descriptors
  Revert "firewire: core: move workqueue handler from 1394 OHCI driver to core function"
  Revert "firewire: core: use mutex to coordinate concurrent calls to flush completions"
  firewire: core: use mutex to coordinate concurrent calls to flush completions
  firewire: core: move workqueue handler from 1394 OHCI driver to core function
  firewire: core: fulfill documentation of fw_iso_context_flush_completions()
  firewire: core: expose kernel API to schedule work item to process isochronous context
  firewire: core: use WARN_ON_ONCE() to avoid superfluous dumps
  ALSA: firewire: use nonatomic PCM operation
  firewire: core: non-atomic memory allocation for isochronous event to user client
  firewire: ohci: operate IT/IR events in sleepable work process instead of tasklet softIRQ
  firewire: core: add local API to queue work item to workqueue specific to isochronous contexts
  firewire: core: allocate workqueue to handle isochronous contexts in card
  firewire: ohci: obsolete direct usage of printk_ratelimit()
  firewire: ohci: deprecate debug parameter
  firewire: core: update fw_device outside of device_find_child()
  firewire: ohci: fix error path to detect initiated reset in TI TSB41BA3D phy
  firewire: core/ohci: minor refactoring for computation of configuration ROM size
  ...

10 files changed, 36 insertions, 7 deletions

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index c827d7d8d800..c72b2a754775 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -615,6 +615,22 @@ static void update_pcm_pointers(struct amdtp_stream *s,
 		// The program in user process should periodically check the status of intermediate
 		// buffer associated to PCM substream to process PCM frames in the buffer, instead
 		// of receiving notification of period elapsed by poll wait.
+		//
+		// Use another work item for period elapsed event to prevent the following AB/BA
+		// deadlock:
+		//
+		//             thread 1                            thread 2
+		// =================================   =================================
+		//       A.work item (process)                pcm ioctl (process)
+		//                 v                                   v
+		//       process_rx_packets()                  B.PCM stream lock
+		//       process_tx_packets()                          v
+		//                 v                        callbacks in snd_pcm_ops
+		//       update_pcm_pointers()                         v
+		//         snd_pcm_elapsed()           fw_iso_context_flush_completions()
+		//  snd_pcm_stream_lock_irqsave()             disable_work_sync()
+		//                 v                                   v
+		//     wait until release of B                wait until A exits
 		if (!pcm->runtime->no_period_wakeup)
 			queue_work(system_highpri_wq, &s->period_work);
 	}
@@ -1055,8 +1071,15 @@ static void generate_rx_packet_descs(struct amdtp_stream *s, struct pkt_desc *de
 
 static inline void cancel_stream(struct amdtp_stream *s)
 {
+	struct work_struct *work = current_work();
+
 	s->packet_index = -1;
-	if (in_softirq())
+
+	// Detect work items for any isochronous context. The work item for pcm_period_work()
+	// should be avoided since the call of snd_pcm_period_elapsed() can reach via
+	// snd_pcm_ops.pointer() under acquiring PCM stream(group) lock and causes dead lock at
+	// snd_pcm_stop_xrun().
+	if (work && work != &s->period_work)
 		amdtp_stream_pcm_abort(s);
 	WRITE_ONCE(s->pcm_buffer_pointer, SNDRV_PCM_POS_XRUN);
 }
@@ -1856,12 +1879,9 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d,
 	struct amdtp_stream *irq_target = d->irq_target;
 
 	if (irq_target && amdtp_stream_running(irq_target)) {
-		// use wq to prevent AB/BA deadlock competition for
-		// substream lock:
-		// fw_iso_context_flush_completions() acquires
-		// lock by ohci_flush_iso_completions(),
-		// amdtp-stream process_rx_packets() attempts to
-		// acquire same lock by snd_pcm_elapsed()
+		// The work item to call snd_pcm_period_elapsed() can reach here by the call of
+		// snd_pcm_ops.pointer(), however less packets would be available then. Therefore
+		// the following call is just for user process contexts.
 		if (current_work() != &s->period_work)
 			fw_iso_context_flush_completions(irq_target->context);
 	}
diff --git a/sound/firewire/bebob/bebob_pcm.c b/sound/firewire/bebob/bebob_pcm.c
index ce49eef0fcba..360ebf3c4ca2 100644
--- a/sound/firewire/bebob/bebob_pcm.c
+++ b/sound/firewire/bebob/bebob_pcm.c
@@ -367,6 +367,7 @@ int snd_bebob_create_pcm_devices(struct snd_bebob *bebob)
 		goto end;
 
 	pcm->private_data = bebob;
+	pcm->nonatomic = true;
 	snprintf(pcm->name, sizeof(pcm->name),
 		 "%s PCM", bebob->card->shortname);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
diff --git a/sound/firewire/dice/dice-pcm.c b/sound/firewire/dice/dice-pcm.c
index d64366217d57..2cf2adb48f2a 100644
--- a/sound/firewire/dice/dice-pcm.c
+++ b/sound/firewire/dice/dice-pcm.c
@@ -441,6 +441,7 @@ int snd_dice_create_pcm(struct snd_dice *dice)
 		if (err < 0)
 			return err;
 		pcm->private_data = dice;
+		pcm->nonatomic = true;
 		strcpy(pcm->name, dice->card->shortname);
 
 		if (capture > 0)
diff --git a/sound/firewire/digi00x/digi00x-pcm.c b/sound/firewire/digi00x/digi00x-pcm.c
index 3bd1575c9d9c..85e65cbc00c4 100644
--- a/sound/firewire/digi00x/digi00x-pcm.c
+++ b/sound/firewire/digi00x/digi00x-pcm.c
@@ -350,6 +350,7 @@ int snd_dg00x_create_pcm_devices(struct snd_dg00x *dg00x)
 		return err;
 
 	pcm->private_data = dg00x;
+	pcm->nonatomic = true;
 	snprintf(pcm->name, sizeof(pcm->name),
 		 "%s PCM", dg00x->card->shortname);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
diff --git a/sound/firewire/fireface/ff-pcm.c b/sound/firewire/fireface/ff-pcm.c
index ec915671a79b..63457d24a288 100644
--- a/sound/firewire/fireface/ff-pcm.c
+++ b/sound/firewire/fireface/ff-pcm.c
@@ -390,6 +390,7 @@ int snd_ff_create_pcm_devices(struct snd_ff *ff)
 		return err;
 
 	pcm->private_data = ff;
+	pcm->nonatomic = true;
 	snprintf(pcm->name, sizeof(pcm->name),
 		 "%s PCM", ff->card->shortname);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_playback_ops);
diff --git a/sound/firewire/fireworks/fireworks_pcm.c b/sound/firewire/fireworks/fireworks_pcm.c
index c3c21860b245..eaf7778211de 100644
--- a/sound/firewire/fireworks/fireworks_pcm.c
+++ b/sound/firewire/fireworks/fireworks_pcm.c
@@ -397,6 +397,7 @@ int snd_efw_create_pcm_devices(struct snd_efw *efw)
 		goto end;
 
 	pcm->private_data = efw;
+	pcm->nonatomic = true;
 	snprintf(pcm->name, sizeof(pcm->name), "%s PCM", efw->card->shortname);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);
diff --git a/sound/firewire/isight.c b/sound/firewire/isight.c
index 806f82c9ceee..b1e059f0d473 100644
--- a/sound/firewire/isight.c
+++ b/sound/firewire/isight.c
@@ -454,6 +454,7 @@ static int isight_create_pcm(struct isight *isight)
 	if (err < 0)
 		return err;
 	pcm->private_data = isight;
+	pcm->nonatomic = true;
 	strcpy(pcm->name, "iSight");
 	isight->pcm = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
 	isight->pcm->ops = &ops;
diff --git a/sound/firewire/motu/motu-pcm.c b/sound/firewire/motu/motu-pcm.c
index d410c2efbde5..f3b48495acae 100644
--- a/sound/firewire/motu/motu-pcm.c
+++ b/sound/firewire/motu/motu-pcm.c
@@ -360,6 +360,7 @@ int snd_motu_create_pcm_devices(struct snd_motu *motu)
 	if (err < 0)
 		return err;
 	pcm->private_data = motu;
+	pcm->nonatomic = true;
 	strcpy(pcm->name, motu->card->shortname);
 
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);
diff --git a/sound/firewire/oxfw/oxfw-pcm.c b/sound/firewire/oxfw/oxfw-pcm.c
index 5f43a0b826d2..8ca9dde54ec6 100644
--- a/sound/firewire/oxfw/oxfw-pcm.c
+++ b/sound/firewire/oxfw/oxfw-pcm.c
@@ -440,6 +440,7 @@ int snd_oxfw_create_pcm(struct snd_oxfw *oxfw)
 		return err;
 
 	pcm->private_data = oxfw;
+	pcm->nonatomic = true;
 	strcpy(pcm->name, oxfw->card->shortname);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
 	if (cap > 0)
diff --git a/sound/firewire/tascam/tascam-pcm.c b/sound/firewire/tascam/tascam-pcm.c
index f6da571707ac..a73003ac11e6 100644
--- a/sound/firewire/tascam/tascam-pcm.c
+++ b/sound/firewire/tascam/tascam-pcm.c
@@ -279,6 +279,7 @@ int snd_tscm_create_pcm_devices(struct snd_tscm *tscm)
 		return err;
 
 	pcm->private_data = tscm;
+	pcm->nonatomic = true;
 	snprintf(pcm->name, sizeof(pcm->name),
 		 "%s PCM", tscm->card->shortname);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);