The tasklet is an old API that should be deprecated, usually can be converted to another decent API. In FireWire driver, a tasklet is still used for offloading the AMDTP PCM stream handling. It can be achieved gracefully with a work queued, too.

This patch replaces the tasklet usage in firewire-lib driver with a simple work. The conversion is fairly straightforward but for the in_interrupt() checks that are replaced with the check using the current_work().

Note that in_interrupt() in amdtp_packet tracepoint is still kept as is. This is the place that is probed by both softirq of 1394 OHCI and a user task of a PCM application, and the work handling is already filtered in amdtp_domain_stream_pcm_pointer().

Signed-off-by: Takashi Iwai tiwai@suse.de --- v1->v2: Drop in_interrupt() conversion in tracepoint

sound/firewire/amdtp-stream.c | 25 +++++++++++++------------ sound/firewire/amdtp-stream.h | 2 +- 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index ee1c428b1fd3..4e2f2bb7879f 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -64,7 +64,7 @@ #define IT_PKT_HEADER_SIZE_CIP 8 // For 2 CIP header. #define IT_PKT_HEADER_SIZE_NO_CIP 0 // Nothing.

-static void pcm_period_tasklet(struct tasklet_struct *t); +static void pcm_period_work(struct work_struct *work);

/** * amdtp_stream_init - initialize an AMDTP stream structure @@ -94,7 +94,7 @@ int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit, s->flags = flags; s->context = ERR_PTR(-1); mutex_init(&s->mutex); - tasklet_setup(&s->period_tasklet, pcm_period_tasklet); + INIT_WORK(&s->period_work, pcm_period_work); s->packet_index = 0;

init_waitqueue_head(&s->callback_wait); @@ -203,7 +203,7 @@ int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,

// Linux driver for 1394 OHCI controller voluntarily flushes isoc // context when total size of accumulated context header reaches - // PAGE_SIZE. This kicks tasklet for the isoc context and brings + // PAGE_SIZE. This kicks work for the isoc context and brings // callback in the middle of scheduled interrupts. // Although AMDTP streams in the same domain use the same events per // IRQ, use the largest size of context header between IT/IR contexts. @@ -333,7 +333,7 @@ EXPORT_SYMBOL(amdtp_stream_get_max_payload); */ void amdtp_stream_pcm_prepare(struct amdtp_stream *s) { - tasklet_kill(&s->period_tasklet); + cancel_work_sync(&s->period_work); s->pcm_buffer_pointer = 0; s->pcm_period_pointer = 0; } @@ -437,13 +437,14 @@ static void update_pcm_pointers(struct amdtp_stream *s, s->pcm_period_pointer += frames; if (s->pcm_period_pointer >= pcm->runtime->period_size) { s->pcm_period_pointer -= pcm->runtime->period_size; - tasklet_hi_schedule(&s->period_tasklet); + queue_work(system_highpri_wq, &s->period_work); } }

-static void pcm_period_tasklet(struct tasklet_struct *t) +static void pcm_period_work(struct work_struct *work) { - struct amdtp_stream *s = from_tasklet(s, t, period_tasklet); + struct amdtp_stream *s = container_of(work, struct amdtp_stream, + period_work); struct snd_pcm_substream *pcm = READ_ONCE(s->pcm);

if (pcm) @@ -794,7 +795,7 @@ static void generate_pkt_descs(struct amdtp_stream *s, struct pkt_desc *descs, static inline void cancel_stream(struct amdtp_stream *s) { s->packet_index = -1; - if (in_interrupt()) + if (current_work() == &s->period_work) amdtp_stream_pcm_abort(s); WRITE_ONCE(s->pcm_buffer_pointer, SNDRV_PCM_POS_XRUN); } @@ -1184,7 +1185,7 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d,

if (irq_target && amdtp_stream_running(irq_target)) { // This function is called in software IRQ context of - // period_tasklet or process context. + // period_work or process context. // // When the software IRQ context was scheduled by software IRQ // context of IT contexts, queued packets were already handled. @@ -1195,9 +1196,9 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d, // immediately to keep better granularity of PCM pointer. // // Later, the process context will sometimes schedules software - // IRQ context of the period_tasklet. Then, no need to flush the + // IRQ context of the period_work. Then, no need to flush the // queue by the same reason as described in the above - if (!in_interrupt()) { + if (current_work() != &s->period_work) { // Queued packet should be processed without any kernel // preemption to keep latency against bus cycle. preempt_disable(); @@ -1263,7 +1264,7 @@ static void amdtp_stream_stop(struct amdtp_stream *s) return; }

- tasklet_kill(&s->period_tasklet); + cancel_work_sync(&s->period_work); fw_iso_context_stop(s->context); fw_iso_context_destroy(s->context); s->context = ERR_PTR(-1); diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h index 703b710aaf7f..2ceb57d1d58e 100644 --- a/sound/firewire/amdtp-stream.h +++ b/sound/firewire/amdtp-stream.h @@ -163,7 +163,7 @@ struct amdtp_stream {

/* For a PCM substream processing. */ struct snd_pcm_substream *pcm; - struct tasklet_struct period_tasklet; + struct work_struct period_work; snd_pcm_uframes_t pcm_buffer_pointer; unsigned int pcm_period_pointer;