ALSA: hda - Revive snd_hda_get_conn_list()

Manage the connection list cache using linked lists instead of
snd_array, and revive snd_hda_get_conn_list() again, so that we don't
have to keep the expanded values locally.
This will reduce the stack usage by recursive call of
snd_hda_get_conn_index() or parse_nid_path() of the generic parser.

The list management doesn't include any mutex protection, thus the
caller needs to take care of race appropriately.

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

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index f4a0f9d..7eab3ae 100644 (file)
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -334,20 +334,51 @@ int snd_hda_get_sub_nodes(struct hda_codec *codec, hda_nid_t nid,
 }
 EXPORT_SYMBOL_HDA(snd_hda_get_sub_nodes);
 
+/* connection list element */
+struct hda_conn_list {
+       struct list_head list;
+       int len;
+       hda_nid_t nid;
+       hda_nid_t conns[0];
+};
+
 /* look up the cached results */
-static hda_nid_t *lookup_conn_list(struct snd_array *array, hda_nid_t nid)
+static struct hda_conn_list *
+lookup_conn_list(struct hda_codec *codec, hda_nid_t nid)
 {
-       int i, len;
-       for (i = 0; i < array->used; ) {
-               hda_nid_t *p = snd_array_elem(array, i);
-               if (nid == *p)
+       struct hda_conn_list *p;
+       list_for_each_entry(p, &codec->conn_list, list) {
+               if (p->nid == nid)
                        return p;
-               len = p[1];
-               i += len + 2;
        }
        return NULL;
 }
 
+static int add_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
+                        const hda_nid_t *list)
+{
+       struct hda_conn_list *p;
+
+       p = kmalloc(sizeof(*p) + len * sizeof(hda_nid_t), GFP_KERNEL);
+       if (!p)
+               return -ENOMEM;
+       p->len = len;
+       p->nid = nid;
+       memcpy(p->conns, list, len * sizeof(hda_nid_t));
+       list_add(&p->list, &codec->conn_list);
+       return 0;
+}
+
+static void remove_conn_list(struct hda_codec *codec)
+{
+       while (!list_empty(&codec->conn_list)) {
+               struct hda_conn_list *p;
+               p = list_first_entry(&codec->conn_list, typeof(*p), list);
+               list_del(&p->list);
+               kfree(p);
+       }
+}
+
 /* read the connection and add to the cache */
 static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
 {
@@ -360,6 +391,49 @@ static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
        return snd_hda_override_conn_list(codec, nid, len, list);
 }
 
+/**
+ * snd_hda_get_conn_list - get connection list
+ * @codec: the HDA codec
+ * @nid: NID to parse
+ * @len: number of connection list entries
+ * @listp: the pointer to store NID list
+ *
+ * Parses the connection list of the given widget and stores the pointer
+ * to the list of NIDs.
+ *
+ * Returns the number of connections, or a negative error code.
+ *
+ * Note that the returned pointer isn't protected against the list
+ * modification.  If snd_hda_override_conn_list() might be called
+ * concurrently, protect with a mutex appropriately.
+ */
+int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
+                         const hda_nid_t **listp)
+{
+       bool added = false;
+
+       for (;;) {
+               int err;
+               const struct hda_conn_list *p;
+
+               /* if the connection-list is already cached, read it */
+               p = lookup_conn_list(codec, nid);
+               if (p) {
+                       if (listp)
+                               *listp = p->conns;
+                       return p->len;
+               }
+               if (snd_BUG_ON(added))
+                       return -EINVAL;
+
+               err = read_and_add_raw_conns(codec, nid);
+               if (err < 0)
+                       return err;
+               added = true;
+       }
+}
+EXPORT_SYMBOL_HDA(snd_hda_get_conn_list);
+
 /**
  * snd_hda_get_connections - copy connection list
  * @codec: the HDA codec
@@ -375,39 +449,20 @@ static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
 int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
                            hda_nid_t *conn_list, int max_conns)
 {
-       struct snd_array *array = &codec->conn_lists;
-       int len;
-       hda_nid_t *p;
-       bool added = false;
+       const hda_nid_t *list;
+       int len = snd_hda_get_conn_list(codec, nid, &list);
 
- again:
-       mutex_lock(&codec->hash_mutex);
-       len = -1;
-       /* if the connection-list is already cached, read it */
-       p = lookup_conn_list(array, nid);
-       if (p) {
-               len = p[1];
-               if (conn_list && len > max_conns) {
+       if (len > 0 && conn_list) {
+               if (len > max_conns) {
                        snd_printk(KERN_ERR "hda_codec: "
                                   "Too many connections %d for NID 0x%x\n",
                                   len, nid);
-                       mutex_unlock(&codec->hash_mutex);
                        return -EINVAL;
                }
-               if (conn_list && len)
-                       memcpy(conn_list, p + 2, len * sizeof(hda_nid_t));
+               memcpy(conn_list, list, len * sizeof(hda_nid_t));
        }
-       mutex_unlock(&codec->hash_mutex);
-       if (len >= 0)
-               return len;
-       if (snd_BUG_ON(added))
-               return -EINVAL;
 
-       len = read_and_add_raw_conns(codec, nid);
-       if (len < 0)
-               return len;
-       added = true;
-       goto again;
+       return len;
 }
 EXPORT_SYMBOL_HDA(snd_hda_get_connections);
 
@@ -519,15 +574,6 @@ int snd_hda_get_raw_connections(struct hda_codec *codec, hda_nid_t nid,
        return conns;
 }
 
-static bool add_conn_list(struct snd_array *array, hda_nid_t nid)
-{
-       hda_nid_t *p = snd_array_new(array);
-       if (!p)
-               return false;
-       *p = nid;
-       return true;
-}
-
 /**
  * snd_hda_override_conn_list - add/modify the connection-list to cache
  * @codec: the HDA codec
@@ -543,28 +589,15 @@ static bool add_conn_list(struct snd_array *array, hda_nid_t nid)
 int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
                               const hda_nid_t *list)
 {
-       struct snd_array *array = &codec->conn_lists;
-       hda_nid_t *p;
-       int i, old_used;
+       struct hda_conn_list *p;
 
-       mutex_lock(&codec->hash_mutex);
-       p = lookup_conn_list(array, nid);
-       if (p)
-               *p = -1; /* invalidate the old entry */
-
-       old_used = array->used;
-       if (!add_conn_list(array, nid) || !add_conn_list(array, len))
-               goto error_add;
-       for (i = 0; i < len; i++)
-               if (!add_conn_list(array, list[i]))
-                       goto error_add;
-       mutex_unlock(&codec->hash_mutex);
-       return 0;
+       p = lookup_conn_list(codec, nid);
+       if (p) {
+               list_del(&p->list);
+               kfree(p);
+       }
 
- error_add:
-       array->used = old_used;
-       mutex_unlock(&codec->hash_mutex);
-       return -ENOMEM;
+       return add_conn_list(codec, nid, len, list);
 }
 EXPORT_SYMBOL_HDA(snd_hda_override_conn_list);
 
@@ -582,10 +615,10 @@ EXPORT_SYMBOL_HDA(snd_hda_override_conn_list);
 int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux,
                           hda_nid_t nid, int recursive)
 {
-       hda_nid_t conn[HDA_MAX_NUM_INPUTS];
+       const hda_nid_t *conn;
        int i, nums;
 
-       nums = snd_hda_get_connections(codec, mux, conn, ARRAY_SIZE(conn));
+       nums = snd_hda_get_conn_list(codec, mux, &conn);
        for (i = 0; i < nums; i++)
                if (conn[i] == nid)
                        return i;
@@ -1186,8 +1219,8 @@ static void snd_hda_codec_free(struct hda_codec *codec)
        snd_array_free(&codec->mixers);
        snd_array_free(&codec->nids);
        snd_array_free(&codec->cvt_setups);
-       snd_array_free(&codec->conn_lists);
        snd_array_free(&codec->spdif_out);
+       remove_conn_list(codec);
        codec->bus->caddr_tbl[codec->addr] = NULL;
        if (codec->patch_ops.free)
                codec->patch_ops.free(codec);
@@ -1257,10 +1290,11 @@ int snd_hda_codec_new(struct hda_bus *bus,
        snd_array_init(&codec->init_pins, sizeof(struct hda_pincfg), 16);
        snd_array_init(&codec->driver_pins, sizeof(struct hda_pincfg), 16);
        snd_array_init(&codec->cvt_setups, sizeof(struct hda_cvt_setup), 8);
-       snd_array_init(&codec->conn_lists, sizeof(hda_nid_t), 64);
        snd_array_init(&codec->spdif_out, sizeof(struct hda_spdif_out), 16);
        snd_array_init(&codec->jacktbl, sizeof(struct hda_jack_tbl), 16);
        snd_array_init(&codec->verbs, sizeof(struct hda_verb *), 8);
+       INIT_LIST_HEAD(&codec->conn_list);
+
        INIT_DELAYED_WORK(&codec->jackpoll_work, hda_jackpoll_work);
 
 #ifdef CONFIG_PM

diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index 9f241d1..93ec747 100644 (file)
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -831,7 +831,7 @@ struct hda_codec {
        struct hda_cache_rec amp_cache; /* cache for amp access */
        struct hda_cache_rec cmd_cache; /* cache for other commands */
 
-       struct snd_array conn_lists;    /* connection-list array */
+       struct list_head conn_list;     /* linked-list of connection-list */
 
        struct mutex spdif_mutex;
        struct mutex control_mutex;
@@ -944,6 +944,8 @@ snd_hda_get_num_conns(struct hda_codec *codec, hda_nid_t nid)
 }
 int snd_hda_get_raw_connections(struct hda_codec *codec, hda_nid_t nid,
                            hda_nid_t *conn_list, int max_conns);
+int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
+                         const hda_nid_t **listp);
 int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int nums,
                          const hda_nid_t *list);
 int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux,

diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
index f5bc185..88f166e 100644 (file)
--- a/sound/pci/hda/hda_generic.c
+++ b/sound/pci/hda/hda_generic.c
@@ -208,7 +208,7 @@ static bool __parse_nid_path(struct hda_codec *codec,
                             int with_aa_mix, struct nid_path *path, int depth)
 {
        struct hda_gen_spec *spec = codec->spec;
-       hda_nid_t conn[16];
+       const hda_nid_t *conn;
        int i, nums;
 
        if (to_nid == spec->mixer_nid) {
@@ -217,7 +217,7 @@ static bool __parse_nid_path(struct hda_codec *codec,
                with_aa_mix = HDA_PARSE_ALL; /* mark aa-mix is included */
        }
 
-       nums = snd_hda_get_connections(codec, to_nid, conn, ARRAY_SIZE(conn));
+       nums = snd_hda_get_conn_list(codec, to_nid, &conn);
        for (i = 0; i < nums; i++) {
                if (conn[i] != from_nid) {
                        /* special case: when from_nid is 0,
@@ -481,12 +481,12 @@ static void activate_amp_in(struct hda_codec *codec, struct nid_path *path,
                            int i, bool enable, bool add_aamix)
 {
        struct hda_gen_spec *spec = codec->spec;
-       hda_nid_t conn[16];
+       const hda_nid_t *conn;
        int n, nums, idx;
        int type;
        hda_nid_t nid = path->path[i];
 
-       nums = snd_hda_get_connections(codec, nid, conn, ARRAY_SIZE(conn));
+       nums = snd_hda_get_conn_list(codec, nid, &conn);
        type = get_wcaps_type(get_wcaps(codec, nid));
        if (type == AC_WID_PIN ||
            (type == AC_WID_AUD_IN && codec->single_adc_amp)) {