mixer: remove alloca() from simple_event_add()

Both of alloca() and automatic variables keep 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/mixer/simple_none.c b/src/mixer/simple_none.c
index 9b0705ccb3cc46c5d78bb5e9bd721582af2be249..e129514c1f9b22f13670e0b26962ed782468fd07 100644 (file)
--- a/src/mixer/simple_none.c
+++ b/src/mixer/simple_none.c
@@ -1610,23 +1610,22 @@ static int simple_event_add(snd_mixer_class_t *class, snd_hctl_elem_t *helem)
        if (snd_hctl_elem_get_interface(helem) != SND_CTL_ELEM_IFACE_MIXER)
                return 0;
        if (strcmp(name, "Capture Source") == 0) {
-               snd_ctl_elem_info_t *info;
+               snd_ctl_elem_info_t info = {0};
                unsigned int k, items;
                int err;
-               snd_ctl_elem_info_alloca(&info);
-               err = snd_hctl_elem_info(helem, info);
+               err = snd_hctl_elem_info(helem, &info);
                assert(err >= 0);
-               if (snd_ctl_elem_info_get_type(info) !=
+               if (snd_ctl_elem_info_get_type(&info) !=
                                                SND_CTL_ELEM_TYPE_ENUMERATED)
                        return 0;
-               items = snd_ctl_elem_info_get_items(info);
+               items = snd_ctl_elem_info_get_items(&info);
                for (k = 0; k < items; ++k) {
                        const char *n;
-                       snd_ctl_elem_info_set_item(info, k);
-                       err = snd_hctl_elem_info(helem, info);
+                       snd_ctl_elem_info_set_item(&info, k);
+                       err = snd_hctl_elem_info(helem, &info);
                        if (err < 0)
                                return err;
-                       n = snd_ctl_elem_info_get_item_name(info);
+                       n = snd_ctl_elem_info_get_item_name(&info);
                        err = simple_add1(class, n, helem, CTL_CAPTURE_SOURCE,
                                          k);
                        if (err < 0)