In all of drivers of ALSA firewire stack, the callback of .pointer and .ack in snd_pcm_ops structure is done in acquired spin_lock of PCM substream, therefore already under disabled kernel preemption.

Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/firewire/amdtp-stream.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 945597ffacc2..1c566ddf0776 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -1751,13 +1751,8 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d, // Later, the process context will sometimes schedules software // IRQ context of the period_work. Then, no need to flush the // queue by the same reason as described in the above - if (current_work() != &s->period_work) { - // Queued packet should be processed without any kernel - // preemption to keep latency against bus cycle. - preempt_disable(); + if (current_work() != &s->period_work) fw_iso_context_flush_completions(irq_target->context); - preempt_enable(); - } }

return READ_ONCE(s->pcm_buffer_pointer); @@ -1777,13 +1772,8 @@ int amdtp_domain_stream_pcm_ack(struct amdtp_domain *d, struct amdtp_stream *s)

// Process isochronous packets for recent isochronous cycle to handle // queued PCM frames. - if (irq_target && amdtp_stream_running(irq_target)) { - // Queued packet should be processed without any kernel - // preemption to keep latency against bus cycle. - preempt_disable(); + if (irq_target && amdtp_stream_running(irq_target)) fw_iso_context_flush_completions(irq_target->context); - preempt_enable(); - }

return 0; }