conf: remove alloca() from snd_func_pcm_id()

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@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/confmisc.c b/src/confmisc.c
index fd10b34149026a3dfb8788228552193fbef8ce0f..2275ccdcf4a6297ff7ce539e47d1d0b13e7187c8 100644 (file)
--- a/src/confmisc.c
+++ b/src/confmisc.c
@@ -969,7 +969,7 @@ int snd_func_pcm_id(snd_config_t **dst, snd_config_t *root, snd_config_t *src, v
 {
        snd_config_t *n;
        snd_ctl_t *ctl = NULL;
-       snd_pcm_info_t *info;
+       snd_pcm_info_t info = {0};
        const char *id;
        long card, device, subdevice = 0;
        int err;
@@ -1009,17 +1009,17 @@ int snd_func_pcm_id(snd_config_t **dst, snd_config_t *root, snd_config_t *src, v
                SNDERR("could not open control for card %li", card);
                goto __error;
        }
-       snd_pcm_info_alloca(&info);
-       snd_pcm_info_set_device(info, device);
-       snd_pcm_info_set_subdevice(info, subdevice);
-       err = snd_ctl_pcm_info(ctl, info);
+       snd_pcm_info_set_device(&info, device);
+       snd_pcm_info_set_subdevice(&info, subdevice);
+       err = snd_ctl_pcm_info(ctl, &info);
        if (err < 0) {
                SNDERR("snd_ctl_pcm_info error: %s", snd_strerror(err));
                goto __error;
        }
        err = snd_config_get_id(src, &id);
        if (err >= 0)
-               err = snd_config_imake_string(dst, id, snd_pcm_info_get_id(info));
+               err = snd_config_imake_string(dst, id,
+                                               snd_pcm_info_get_id(&info));
       __error:
        if (ctl)
                snd_ctl_close(ctl);