mixer: remove alloca() from elem_write_switch_constant()

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 c1f2b295aeed69ccb4c519df8d9f7802179090a7..13666b5089a17de0d0c45892cf92fe40fd287517 100644 (file)
--- a/src/mixer/simple_none.c
+++ b/src/mixer/simple_none.c
@@ -499,16 +499,15 @@ static int elem_write_switch(selem_none_t *s, int dir, selem_ctl_type_t type)
 
 static int elem_write_switch_constant(selem_none_t *s, selem_ctl_type_t type, int val)
 {
-       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, !!val);
-       if ((err = snd_hctl_elem_write(c->elem, ctl)) < 0)
+               snd_ctl_elem_value_set_integer(&ctl, idx, !!val);
+       if ((err = snd_hctl_elem_write(c->elem, &ctl)) < 0)
                return err;
        return 0;
 }