ALSA: Core - clean up snd_card_set_id* calls and remove possible id collision

Move locking outside snd_card_set_id_internal() function and rename it
to snd_card_set_id_no_lock() for better function description.

User defined id is just copied to card structure at allocation time.
The real unique id procedure is called in snd_card_register() to
ensure real atomicity.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/init.c b/sound/core/init.c
index a578d05..d5d40d7 100644 (file)
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -153,7 +153,7 @@ int snd_card_create(int idx, const char *xid,
        if (!card)
                return -ENOMEM;
        if (xid)
-               snd_card_set_id(card, xid);
+               strlcpy(card->id, xid, sizeof(card->id));
        err = 0;
        mutex_lock(&snd_card_mutex);
        if (idx < 0) {
@@ -476,16 +476,12 @@ int snd_card_free(struct snd_card *card)
 
 EXPORT_SYMBOL(snd_card_free);
 
-static void snd_card_set_id_internal(struct snd_card *card, const char *nid,
-                                    int do_locking)
+static void snd_card_set_id_no_lock(struct snd_card *card, const char *nid)
 {
        int i, len, idx_flag = 0, loops = SNDRV_CARDS;
        const char *spos, *src;
        char *id;
        
-       /* check if user specified own card->id */
-       if (card->id[0] != '\0')
-               return;
        if (nid == NULL) {
                id = card->shortname;
                spos = src = id;
@@ -522,16 +518,10 @@ static void snd_card_set_id_internal(struct snd_card *card, const char *nid,
                }
                if (!snd_info_check_reserved_words(id))
                        goto __change;
-               if (do_locking)
-                       mutex_lock(&snd_card_mutex);
                for (i = 0; i < snd_ecards_limit; i++) {
-                       if (snd_cards[i] && !strcmp(snd_cards[i]->id, id)) {
-                               mutex_unlock(&snd_card_mutex);
+                       if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
                                goto __change;
-                       }
                }
-               if (do_locking)
-                       mutex_unlock(&snd_card_mutex);
                break;
 
              __change:
@@ -566,7 +556,12 @@ static void snd_card_set_id_internal(struct snd_card *card, const char *nid,
  */
 void snd_card_set_id(struct snd_card *card, const char *nid)
 {
-       snd_card_set_id_internal(card, nid, 1);
+       /* check if user specified own card->id */
+       if (card->id[0] != '\0')
+               return;
+       mutex_lock(&snd_card_mutex);
+       snd_card_set_id_no_lock(card, nid);
+       mutex_unlock(&snd_card_mutex);
 }
 EXPORT_SYMBOL(snd_card_set_id);
 
@@ -663,8 +658,7 @@ int snd_card_register(struct snd_card *card)
                mutex_unlock(&snd_card_mutex);
                return 0;
        }
-       if (card->id[0] == '\0')
-               snd_card_set_id_internal(card, NULL, 0);
+       snd_card_set_id_no_lock(card, card->id[0] == '\0' ? NULL : card->id);
        snd_cards[card->number] = card;
        mutex_unlock(&snd_card_mutex);
        init_info_for_card(card);