mixer: remove alloca() from elem_write_route()

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 0ebaf5e823cc8fb9a1f0e1e96727f269f25e9f07..d0e89632c123dcbab738b08a8355151713857000 100644 (file)
--- a/src/mixer/simple_none.c
+++ b/src/mixer/simple_none.c
@@ -514,19 +514,18 @@ static int elem_write_switch_constant(selem_none_t *s, selem_ctl_type_t type, in
 
 static int elem_write_route(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 * c->values; idx++)
-               snd_ctl_elem_value_set_integer(ctl, idx, 0);
+               snd_ctl_elem_value_set_integer(&ctl, idx, 0);
        for (idx = 0; idx < c->values; idx++)
-               snd_ctl_elem_value_set_integer(ctl, idx * c->values + idx,
+               snd_ctl_elem_value_set_integer(&ctl, idx * c->values + 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;
 }