mixer: remove alloca() from init_db_range()

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 05dde4132e2398b1f75671000118c70f9a493c7b..0799ceb3ee15355cd3ca1deb4e425a5ae60408a7 100644 (file)
--- a/src/mixer/simple_none.c
+++ b/src/mixer/simple_none.c
@@ -1098,7 +1098,7 @@ static int convert_to_dB(snd_hctl_elem_t *ctl, struct selem_str *rec,
  */
 static int init_db_range(snd_hctl_elem_t *ctl, struct selem_str *rec)
 {
-       snd_ctl_elem_info_t *info;
+       snd_ctl_elem_info_t info = {0};
        unsigned int *tlv = NULL;
        const unsigned int tlv_size = 4096;
        unsigned int *dbrec;
@@ -1109,10 +1109,9 @@ static int init_db_range(snd_hctl_elem_t *ctl, struct selem_str *rec)
        if (rec->db_initialized)
                return 0;
 
-       snd_ctl_elem_info_alloca(&info);
-       if (snd_hctl_elem_info(ctl, info) < 0)
+       if (snd_hctl_elem_info(ctl, &info) < 0)
                goto error;
-       if (!snd_ctl_elem_info_is_tlv_readable(info))
+       if (!snd_ctl_elem_info_is_tlv_readable(&info))
                goto error;
        tlv = malloc(tlv_size);
        if (!tlv)