ALSA: control - introduce snd_ctl_notify_one() helper

This helper is required for the following generic LED mute
patch. The helper also simplifies some other functions.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210317172945.842280-2-perex@perex.cz
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/sound/control.h b/include/sound/control.h
index 77d9fa10812d01dcc35f0b24b6fc5a66cbe9bb94..22f3d48163ff4b8d395546f9e3e442092f4cc36e 100644 (file)
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -115,6 +115,7 @@ typedef int (*snd_kctl_ioctl_func_t) (struct snd_card * card,
                                      unsigned int cmd, unsigned long arg);
 
 void snd_ctl_notify(struct snd_card * card, unsigned int mask, struct snd_ctl_elem_id * id);
+void snd_ctl_notify_one(struct snd_card * card, unsigned int mask, struct snd_kcontrol * kctl, unsigned int ioff);
 
 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new * kcontrolnew, void * private_data);
 void snd_ctl_free_one(struct snd_kcontrol * kcontrol);
@@ -123,8 +124,7 @@ int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);
 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, bool add_on_replace);
 int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);
 int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);
-int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
-                       int active);
+int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id, int active);
 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card * card, unsigned int numid);
 struct snd_kcontrol *snd_ctl_find_id(struct snd_card * card, struct snd_ctl_elem_id *id);
 

diff --git a/sound/core/control.c b/sound/core/control.c
index 5165741a8400f96b502cfa36713b69669dcac96f..8a5cedb0a4bea3ff4d9ba3d43484be19d6ce23d9 100644 (file)
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -181,6 +181,27 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 }
 EXPORT_SYMBOL(snd_ctl_notify);
 
+/**
+ * snd_ctl_notify_one - Send notification to user-space for a control change
+ * @card: the card to send notification
+ * @mask: the event mask, SNDRV_CTL_EVENT_*
+ * @kctl: the pointer with the control instance
+ * @ioff: the additional offset to the control index
+ *
+ * This function calls snd_ctl_notify() and does additional jobs
+ * like LED state changes.
+ */
+void snd_ctl_notify_one(struct snd_card *card, unsigned int mask,
+                       struct snd_kcontrol *kctl, unsigned int ioff)
+{
+       struct snd_ctl_elem_id id = kctl->id;
+
+       id.index += ioff;
+       id.numid += ioff;
+       snd_ctl_notify(card, mask, &id);
+}
+EXPORT_SYMBOL(snd_ctl_notify_one);
+
 /**
  * snd_ctl_new - create a new control instance with some elements
  * @kctl: the pointer to store new control instance
@@ -342,7 +363,6 @@ static int __snd_ctl_add_replace(struct snd_card *card,
 {
        struct snd_ctl_elem_id id;
        unsigned int idx;
-       unsigned int count;
        struct snd_kcontrol *old;
        int err;
 
@@ -376,10 +396,8 @@ static int __snd_ctl_add_replace(struct snd_card *card,
        kcontrol->id.numid = card->last_numid + 1;
        card->last_numid += kcontrol->count;
 
-       id = kcontrol->id;
-       count = kcontrol->count;
-       for (idx = 0; idx < count; idx++, id.index++, id.numid++)
-               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
+       for (idx = 0; idx < kcontrol->count; idx++)
+               snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);
 
        return 0;
 }
@@ -462,16 +480,14 @@ EXPORT_SYMBOL(snd_ctl_replace);
  */
 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 {
-       struct snd_ctl_elem_id id;
        unsigned int idx;
 
        if (snd_BUG_ON(!card || !kcontrol))
                return -EINVAL;
        list_del(&kcontrol->list);
        card->controls_count -= kcontrol->count;
-       id = kcontrol->id;
-       for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
-               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
+       for (idx = 0; idx < kcontrol->count; idx++)
+               snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);
        snd_ctl_free_one(kcontrol);
        return 0;
 }
@@ -584,11 +600,13 @@ int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
                vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
        }
        snd_ctl_build_ioff(id, kctl, index_offset);
-       ret = 1;
+       downgrade_write(&card->controls_rwsem);
+       snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);
+       up_read(&card->controls_rwsem);
+       return 1;
+
  unlock:
        up_write(&card->controls_rwsem);
-       if (ret > 0)
-               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
        return ret;
 }
 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
@@ -1110,25 +1128,34 @@ static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
        unsigned int index_offset;
        int result;
 
+       down_write(&card->controls_rwsem);
        kctl = snd_ctl_find_id(card, &control->id);
-       if (kctl == NULL)
+       if (kctl == NULL) {
+               up_write(&card->controls_rwsem);
                return -ENOENT;
+       }
 
        index_offset = snd_ctl_get_ioff(kctl, &control->id);
        vd = &kctl->vd[index_offset];
        if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
            (file && vd->owner && vd->owner != file)) {
+               up_write(&card->controls_rwsem);
                return -EPERM;
        }
 
        snd_ctl_build_ioff(&control->id, kctl, index_offset);
        result = kctl->put(kctl, control);
-       if (result < 0)
+       if (result < 0) {
+               up_write(&card->controls_rwsem);
                return result;
+       }
 
        if (result > 0) {
-               struct snd_ctl_elem_id id = control->id;
-               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
+               downgrade_write(&card->controls_rwsem);
+               snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);
+               up_read(&card->controls_rwsem);
+       } else {
+               up_write(&card->controls_rwsem);
        }
 
        return 0;
@@ -1150,9 +1177,7 @@ static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
        if (result < 0)
                goto error;
 
-       down_write(&card->controls_rwsem);
        result = snd_ctl_elem_write(card, file, control);
-       up_write(&card->controls_rwsem);
        if (result < 0)
                goto error;
 
@@ -1301,7 +1326,6 @@ static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
 {
        struct user_element *ue = kctl->private_data;
        unsigned int *container;
-       struct snd_ctl_elem_id id;
        unsigned int mask = 0;
        int i;
        int change;
@@ -1333,10 +1357,8 @@ static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
        ue->tlv_data_size = size;
 
        mask |= SNDRV_CTL_EVENT_MASK_TLV;
-       for (i = 0; i < kctl->count; ++i) {
-               snd_ctl_build_ioff(&id, kctl, i);
-               snd_ctl_notify(ue->card, mask, &id);
-       }
+       for (i = 0; i < kctl->count; ++i)
+               snd_ctl_notify_one(ue->card, mask, kctl, i);
 
        return change;
 }