ALSA: Introduce snd_card_create()

Introduced snd_card_create() function as a replacement of snd_card_new().
The new function returns a negative error code so that the probe callback
can return the proper error code, while snd_card_new() can give only NULL
check.

The old snd_card_new() is still provided as an inline function but with
__deprecated attribute.  It'll be removed soon later.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

2 files changed, 44 insertions, 17 deletions

diff --git a/include/sound/core.h b/include/sound/core.h
index f632484bc743..25420c3b5513 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -296,8 +296,20 @@ int snd_card_locked(int card);
 extern int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int cmd);
 #endif
 
+int snd_card_create(int idx, const char *id,
+                    struct module *module, int extra_size,
+                    struct snd_card **card_ret);
+
+static inline __deprecated
 struct snd_card *snd_card_new(int idx, const char *id,
-                         struct module *module, int extra_size);
+                              struct module *module, int extra_size)
+{
+        struct snd_card *card;
+        if (snd_card_create(idx, id, module, extra_size, &card) < 0)
+                return NULL;
+        return card;
+}
+
 int snd_card_disconnect(struct snd_card *card);
 int snd_card_free(struct snd_card *card);
 int snd_card_free_when_closed(struct snd_card *card);
diff --git a/sound/core/init.c b/sound/core/init.c
index 0d5520c415d3..dc4b80c7f311 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -121,31 +121,44 @@ static inline int init_info_for_card(struct snd_card *card)
 #endif
 
 /**
- *  snd_card_new - create and initialize a soundcard structure
+ *  snd_card_create - create and initialize a soundcard structure
  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
  *  @xid: card identification (ASCII string)
  *  @module: top level module for locking
  *  @extra_size: allocate this extra size after the main soundcard structure
+ *  @card_ret: the pointer to store the created card instance
  *
  *  Creates and initializes a soundcard structure.
  *
- *  Returns kmallocated snd_card structure. Creates the ALSA control interface
- *  (which is blocked until snd_card_register function is called).
+ *  The function allocates snd_card instance via kzalloc with the given
+ *  space for the driver to use freely.  The allocated struct is stored
+ *  in the given card_ret pointer.
+ *
+ *  Returns zero if successful or a negative error code.
  */
-struct snd_card *snd_card_new(int idx, const char *xid,
-                         struct module *module, int extra_size)
+int snd_card_create(int idx, const char *xid,
+                    struct module *module, int extra_size,
+                    struct snd_card **card_ret)
 {
         struct snd_card *card;
         int err, idx2;
 
+        if (snd_BUG_ON(!card_ret))
+                return -EINVAL;
+        *card_ret = NULL;
+
         if (extra_size < 0)
                 extra_size = 0;
         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
-        if (card == NULL)
-                return NULL;
+        if (!card)
+                return -ENOMEM;
         if (xid) {
-                if (!snd_info_check_reserved_words(xid))
+                if (!snd_info_check_reserved_words(xid)) {
+                        snd_printk(KERN_ERR
+                                   "given id string '%s' is reserved.\n", xid);
+                        err = -EBUSY;
                         goto __error;
+                }
                 strlcpy(card->id, xid, sizeof(card->id));
         }
         err = 0;
@@ -202,26 +215,28 @@ struct snd_card *snd_card_new(int idx, const char *xid,
 #endif
         /* the control interface cannot be accessed from the user space until */
         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
-        if ((err = snd_ctl_create(card)) < 0) {
-                snd_printd("unable to register control minors\n");
+        err = snd_ctl_create(card);
+        if (err < 0) {
+                snd_printk(KERN_ERR "unable to register control minors\n");
                 goto __error;
         }
-        if ((err = snd_info_card_create(card)) < 0) {
-                snd_printd("unable to create card info\n");
+        err = snd_info_card_create(card);
+        if (err < 0) {
+                snd_printk(KERN_ERR "unable to create card info\n");
                 goto __error_ctl;
         }
         if (extra_size > 0)
                 card->private_data = (char *)card + sizeof(struct snd_card);
-        return card;
+        *card_ret = card;
+        return 0;
 
       __error_ctl:
         snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
       __error:
         kfree(card);
-        return NULL;
+        return err;
 }
-
-EXPORT_SYMBOL(snd_card_new);
+EXPORT_SYMBOL(snd_card_create);
 
 /* return non-zero if a card is already locked */
 int snd_card_locked(int card)