ALSA: firewire-lib: remove useless operations for kernel preemption

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>
Link: https://lore.kernel.org/r/20210606025651.29970-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index b37cec3..4d78900 100644 (file)
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -1755,13 +1755,8 @@ 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);
@@ -1781,13 +1776,8 @@ 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;
 }