[alsa-devel] [PATCH 13/34] pcm: remove alloca() from snd_pcm_hw_change_timer()

[Takashi Sakamoto]

Both of alloca() and automatic variables keeps storages on stack, while
the former generates more instructions than the latter. It's better to use
the latter if the size of storage is computable at pre-compile or compile
time; i.e. just for structures.

This commit obsolete usages of alloca() with automatic variables.

Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 src/pcm/pcm_hw.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c
index 0daaccc..864d5fa 100644
--- a/src/pcm/pcm_hw.c
+++ b/src/pcm/pcm_hw.c
@@ -351,12 +351,11 @@ static void snd_pcm_hw_close_timer(snd_pcm_hw_t *hw)
 static int snd_pcm_hw_change_timer(snd_pcm_t *pcm, int enable)
 {
 	snd_pcm_hw_t *hw = pcm->private_data;
-	snd_timer_params_t *params;
+	snd_timer_params_t params = {0};
 	unsigned int suspend, resume;
 	int err;
 	
 	if (enable) {
-		snd_timer_params_alloca(&params);
 		err = snd_timer_hw_open(&hw->period_timer,
 				"hw-pcm-period-event",
 				SND_TIMER_CLASS_PCM, SND_TIMER_SCLASS_NONE,
@@ -406,11 +405,11 @@ static int snd_pcm_hw_change_timer(snd_pcm_t *pcm, int enable)
 				resume = 1<<SND_TIMER_EVENT_MCONTINUE;
 			}
 		}
-		snd_timer_params_set_auto_start(params, 1);
-		snd_timer_params_set_ticks(params, 1);
-		snd_timer_params_set_filter(params, (1<<SND_TIMER_EVENT_TICK) |
+		snd_timer_params_set_auto_start(&params, 1);
+		snd_timer_params_set_ticks(&params, 1);
+		snd_timer_params_set_filter(&params, (1<<SND_TIMER_EVENT_TICK) |
 					    suspend | resume);
-		err = snd_timer_params(hw->period_timer, params);
+		err = snd_timer_params(hw->period_timer, &params);
 		if (err < 0) {
 			snd_pcm_hw_close_timer(hw);
 			return err;
-- 
2.7.4