mixer: remove alloca() from elem_write_switch()

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 d0e800e60d42cf722a51d3b4f940e77f547db246..c1f2b295aeed69ccb4c519df8d9f7802179090a7 100644 (file)
--- a/src/mixer/simple_none.c
+++ b/src/mixer/simple_none.c
@@ -483,17 +483,16 @@ static int elem_write_volume(selem_none_t *s, int dir, selem_ctl_type_t type)
 
 static int elem_write_switch(selem_none_t *s, int dir, selem_ctl_type_t type)
 {
-       snd_ctl_elem_value_t *ctl;
+       snd_ctl_elem_value_t ctl = {0};
        unsigned int idx;
        int err;
        selem_ctl_t *c = &s->ctls[type];
-       snd_ctl_elem_value_alloca(&ctl);
-       if ((err = snd_hctl_elem_read(c->elem, ctl)) < 0)
+       if ((err = snd_hctl_elem_read(c->elem, &ctl)) < 0)
                return err;
        for (idx = 0; idx < c->values; idx++)
-               snd_ctl_elem_value_set_integer(ctl, idx,
+               snd_ctl_elem_value_set_integer(&ctl, idx,
                                        !!(s->str[dir].sw & (1 << idx)));
-       if ((err = snd_hctl_elem_write(c->elem, ctl)) < 0)
+       if ((err = snd_hctl_elem_write(c->elem, &ctl)) < 0)
                return err;
        return 0;
 }