[ALSA] Fix disconnection of proc interface

- Add the linked list to each proc entry to enable a single-shot
  disconnection (unregister)
- Deprecate snd_info_unregister(), use snd_info_free_entry()
- Removed NULL checks of snd_info_free_entry()

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

15 files changed, 90 insertions, 117 deletions

diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
index 8bd0dcc93eba..cbd8a63282b6 100644
--- a/sound/core/hwdep.c
+++ b/sound/core/hwdep.c
@@ -497,7 +497,7 @@ static void __init snd_hwdep_proc_init(void)
 
 static void __exit snd_hwdep_proc_done(void)
 {
-        snd_info_unregister(snd_hwdep_proc_entry);
+        snd_info_free_entry(snd_hwdep_proc_entry);
 }
 #else /* !CONFIG_PROC_FS */
 #define snd_hwdep_proc_init()
diff --git a/sound/core/info.c b/sound/core/info.c
index 340332c6d973..9663b6be9c3a 100644
--- a/sound/core/info.c
+++ b/sound/core/info.c
@@ -78,6 +78,7 @@ struct snd_info_private_data {
 
 static int snd_info_version_init(void);
 static int snd_info_version_done(void);
+static void snd_info_disconnect(struct snd_info_entry *entry);
 
 
 /* resize the proc r/w buffer */
@@ -304,7 +305,7 @@ static int snd_info_entry_open(struct inode *inode, struct file *file)
         mutex_lock(&info_mutex);
         p = PDE(inode);
         entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
-        if (entry == NULL || entry->disconnected) {
+        if (entry == NULL || ! entry->p) {
                 mutex_unlock(&info_mutex);
                 return -ENODEV;
         }
@@ -586,10 +587,10 @@ int __exit snd_info_done(void)
         snd_info_version_done();
         if (snd_proc_root) {
 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
-                snd_info_unregister(snd_seq_root);
+                snd_info_free_entry(snd_seq_root);
 #endif
 #ifdef CONFIG_SND_OSSEMUL
-                snd_info_unregister(snd_oss_root);
+                snd_info_free_entry(snd_oss_root);
 #endif
                 snd_remove_proc_entry(&proc_root, snd_proc_root);
         }
@@ -648,17 +649,28 @@ int snd_info_card_register(struct snd_card *card)
  * de-register the card proc file
  * called from init.c
  */
-int snd_info_card_free(struct snd_card *card)
+void snd_info_card_disconnect(struct snd_card *card)
 {
-        snd_assert(card != NULL, return -ENXIO);
+        snd_assert(card != NULL, return);
+        mutex_lock(&info_mutex);
         if (card->proc_root_link) {
                 snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
                 card->proc_root_link = NULL;
         }
-        if (card->proc_root) {
-                snd_info_unregister(card->proc_root);
-                card->proc_root = NULL;
-        }
+        if (card->proc_root)
+                snd_info_disconnect(card->proc_root);
+        mutex_unlock(&info_mutex);
+}
+
+/*
+ * release the card proc file resources
+ * called from init.c
+ */
+int snd_info_card_free(struct snd_card *card)
+{
+        snd_assert(card != NULL, return -ENXIO);
+        snd_info_free_entry(card->proc_root);
+        card->proc_root = NULL;
         return 0;
 }
 
@@ -767,6 +779,8 @@ static struct snd_info_entry *snd_info_create_entry(const char *name)
         entry->mode = S_IFREG | S_IRUGO;
         entry->content = SNDRV_INFO_CONTENT_TEXT;
         mutex_init(&entry->access);
+        INIT_LIST_HEAD(&entry->children);
+        INIT_LIST_HEAD(&entry->list);
         return entry;
 }
 
@@ -819,30 +833,35 @@ struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 
 EXPORT_SYMBOL(snd_info_create_card_entry);
 
-static int snd_info_dev_free_entry(struct snd_device *device)
+static void snd_info_disconnect(struct snd_info_entry *entry)
 {
-        struct snd_info_entry *entry = device->device_data;
-        snd_info_free_entry(entry);
-        return 0;
-}
+        struct list_head *p, *n;
+        struct proc_dir_entry *root;
 
-static int snd_info_dev_register_entry(struct snd_device *device)
-{
-        struct snd_info_entry *entry = device->device_data;
-        return snd_info_register(entry);
+        list_for_each_safe(p, n, &entry->children) {
+                snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
+        }
+
+        if (! entry->p)
+                return;
+        list_del_init(&entry->list);
+        root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
+        snd_assert(root, return);
+        snd_remove_proc_entry(root, entry->p);
+        entry->p = NULL;
 }
 
-static int snd_info_dev_disconnect_entry(struct snd_device *device)
+static int snd_info_dev_free_entry(struct snd_device *device)
 {
         struct snd_info_entry *entry = device->device_data;
-        entry->disconnected = 1;
+        snd_info_free_entry(entry);
         return 0;
 }
 
-static int snd_info_dev_unregister_entry(struct snd_device *device)
+static int snd_info_dev_register_entry(struct snd_device *device)
 {
         struct snd_info_entry *entry = device->device_data;
-        return snd_info_unregister(entry);
+        return snd_info_register(entry);
 }
 
 /**
@@ -871,8 +890,7 @@ int snd_card_proc_new(struct snd_card *card, const char *name,
         static struct snd_device_ops ops = {
                 .dev_free = snd_info_dev_free_entry,
                 .dev_register = snd_info_dev_register_entry,
-                .dev_disconnect = snd_info_dev_disconnect_entry,
-                .dev_unregister = snd_info_dev_unregister_entry
+                /* disconnect is done via snd_info_card_disconnect() */
         };
         struct snd_info_entry *entry;
         int err;
@@ -901,6 +919,11 @@ void snd_info_free_entry(struct snd_info_entry * entry)
 {
         if (entry == NULL)
                 return;
+        if (entry->p) {
+                mutex_lock(&info_mutex);
+                snd_info_disconnect(entry);
+                mutex_unlock(&info_mutex);
+        }
         kfree(entry->name);
         if (entry->private_free)
                 entry->private_free(entry);
@@ -935,38 +958,14 @@ int snd_info_register(struct snd_info_entry * entry)
         p->size = entry->size;
         p->data = entry;
         entry->p = p;
+        if (entry->parent)
+                list_add_tail(&entry->list, &entry->parent->children);
         mutex_unlock(&info_mutex);
         return 0;
 }
 
 EXPORT_SYMBOL(snd_info_register);
 
-/**
- * snd_info_unregister - de-register the info entry
- * @entry: the info entry
- *
- * De-registers the info entry and releases the instance.
- *
- * Returns zero if successful, or a negative error code on failure.
- */
-int snd_info_unregister(struct snd_info_entry * entry)
-{
-        struct proc_dir_entry *root;
-
-        if (! entry)
-                return 0;
-        snd_assert(entry->p != NULL, return -ENXIO);
-        root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
-        snd_assert(root, return -ENXIO);
-        mutex_lock(&info_mutex);
-        snd_remove_proc_entry(root, entry->p);
-        mutex_unlock(&info_mutex);
-        snd_info_free_entry(entry);
-        return 0;
-}
-
-EXPORT_SYMBOL(snd_info_unregister);
-
 /*
 
  */
@@ -999,8 +998,7 @@ static int __init snd_info_version_init(void)
 
 static int __exit snd_info_version_done(void)
 {
-        if (snd_info_version_entry)
-                snd_info_unregister(snd_info_version_entry);
+        snd_info_free_entry(snd_info_version_entry);
         return 0;
 }
 
diff --git a/sound/core/info_oss.c b/sound/core/info_oss.c
index bb2c40d0ab66..3ebc34919c76 100644
--- a/sound/core/info_oss.c
+++ b/sound/core/info_oss.c
@@ -131,10 +131,8 @@ int snd_info_minor_register(void)
 
 int snd_info_minor_unregister(void)
 {
-        if (snd_sndstat_proc_entry) {
-                snd_info_unregister(snd_sndstat_proc_entry);
-                snd_sndstat_proc_entry = NULL;
-        }
+        snd_info_free_entry(snd_sndstat_proc_entry);
+        snd_sndstat_proc_entry = NULL;
         return 0;
 }
 
diff --git a/sound/core/init.c b/sound/core/init.c
index 4d9258884e44..1ecb029ff4c9 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -310,6 +310,7 @@ int snd_card_disconnect(struct snd_card *card)
         if (err < 0)
                 snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
 
+        snd_info_card_disconnect(card);
         return 0;       
 }
 
@@ -360,7 +361,7 @@ int snd_card_free(struct snd_card *card)
         }
         if (card->private_free)
                 card->private_free(card);
-        snd_info_unregister(card->proc_id);
+        snd_info_free_entry(card->proc_id);
         if (snd_info_card_free(card) < 0) {
                 snd_printk(KERN_WARNING "unable to free card info\n");
                 /* Not fatal error */
@@ -625,9 +626,9 @@ int __init snd_card_info_init(void)
 
 int __exit snd_card_info_done(void)
 {
-        snd_info_unregister(snd_card_info_entry);
+        snd_info_free_entry(snd_card_info_entry);
 #ifdef MODULE
-        snd_info_unregister(snd_card_module_info_entry);
+        snd_info_free_entry(snd_card_module_info_entry);
 #endif
         return 0;
 }
diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index 75a9505c7445..00c95def95aa 100644
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -1193,10 +1193,8 @@ static void snd_mixer_oss_proc_init(struct snd_mixer_oss *mixer)
 
 static void snd_mixer_oss_proc_done(struct snd_mixer_oss *mixer)
 {
-        if (mixer->proc_entry) {
-                snd_info_unregister(mixer->proc_entry);
-                mixer->proc_entry = NULL;
-        }
+        snd_info_free_entry(mixer->proc_entry);
+        mixer->proc_entry = NULL;
 }
 #else /* !CONFIG_PROC_FS */
 #define snd_mixer_oss_proc_init(mix)
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index 472fce0ee0e8..a92b93e5ebd5 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -2846,11 +2846,9 @@ static void snd_pcm_oss_proc_done(struct snd_pcm *pcm)
         int stream;
         for (stream = 0; stream < 2; ++stream) {
                 struct snd_pcm_str *pstr = &pcm->streams[stream];
-                if (pstr->oss.proc_entry) {
-                        snd_info_unregister(pstr->oss.proc_entry);
-                        pstr->oss.proc_entry = NULL;
-                        snd_pcm_oss_proc_free_setup_list(pstr);
-                }
+                snd_info_free_entry(pstr->oss.proc_entry);
+                pstr->oss.proc_entry = NULL;
+                snd_pcm_oss_proc_free_setup_list(pstr);
         }
 }
 #else /* !CONFIG_SND_VERBOSE_PROCFS */
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 7581edd7b9ff..b8602471f7e5 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -494,19 +494,13 @@ static int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr)
 static int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr)
 {
 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
-        if (pstr->proc_xrun_debug_entry) {
-                snd_info_unregister(pstr->proc_xrun_debug_entry);
-                pstr->proc_xrun_debug_entry = NULL;
-        }
+        snd_info_free_entry(pstr->proc_xrun_debug_entry);
+        pstr->proc_xrun_debug_entry = NULL;
 #endif
-        if (pstr->proc_info_entry) {
-                snd_info_unregister(pstr->proc_info_entry);
-                pstr->proc_info_entry = NULL;
-        }
-        if (pstr->proc_root) {
-                snd_info_unregister(pstr->proc_root);
-                pstr->proc_root = NULL;
-        }
+        snd_info_free_entry(pstr->proc_info_entry);
+        pstr->proc_info_entry = NULL;
+        snd_info_free_entry(pstr->proc_root);
+        pstr->proc_root = NULL;
         return 0;
 }
 
@@ -570,29 +564,19 @@ static int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream)
 
         return 0;
 }
-                
+
 static int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream)
 {
-        if (substream->proc_info_entry) {
-                snd_info_unregister(substream->proc_info_entry);
-                substream->proc_info_entry = NULL;
-        }
-        if (substream->proc_hw_params_entry) {
-                snd_info_unregister(substream->proc_hw_params_entry);
-                substream->proc_hw_params_entry = NULL;
-        }
-        if (substream->proc_sw_params_entry) {
-                snd_info_unregister(substream->proc_sw_params_entry);
-                substream->proc_sw_params_entry = NULL;
-        }
-        if (substream->proc_status_entry) {
-                snd_info_unregister(substream->proc_status_entry);
-                substream->proc_status_entry = NULL;
-        }
-        if (substream->proc_root) {
-                snd_info_unregister(substream->proc_root);
-                substream->proc_root = NULL;
-        }
+        snd_info_free_entry(substream->proc_info_entry);
+        substream->proc_info_entry = NULL;
+        snd_info_free_entry(substream->proc_hw_params_entry);
+        substream->proc_hw_params_entry = NULL;
+        snd_info_free_entry(substream->proc_sw_params_entry);
+        substream->proc_sw_params_entry = NULL;
+        snd_info_free_entry(substream->proc_status_entry);
+        substream->proc_status_entry = NULL;
+        snd_info_free_entry(substream->proc_root);
+        substream->proc_root = NULL;
         return 0;
 }
 #else /* !CONFIG_SND_VERBOSE_PROCFS */
@@ -1090,8 +1074,7 @@ static void snd_pcm_proc_init(void)
 
 static void snd_pcm_proc_done(void)
 {
-        if (snd_pcm_proc_entry)
-                snd_info_unregister(snd_pcm_proc_entry);
+        snd_info_free_entry(snd_pcm_proc_entry);
 }
 
 #else /* !CONFIG_PROC_FS */
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index 067d2056db9a..be030cb4d373 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -101,7 +101,7 @@ int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
 {
         snd_pcm_lib_preallocate_dma_free(substream);
 #ifdef CONFIG_SND_VERBOSE_PROCFS
-        snd_info_unregister(substream->proc_prealloc_entry);
+        snd_info_free_entry(substream->proc_prealloc_entry);
         substream->proc_prealloc_entry = NULL;
 #endif
         return 0;
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 8c15c66eb4aa..51577c22f8ce 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -1599,7 +1599,7 @@ static int snd_rawmidi_dev_unregister(struct snd_device *device)
         mutex_lock(&register_mutex);
         list_del(&rmidi->list);
         if (rmidi->proc_entry) {
-                snd_info_unregister(rmidi->proc_entry);
+                snd_info_free_entry(rmidi->proc_entry);
                 rmidi->proc_entry = NULL;
         }
 #ifdef CONFIG_SND_OSSEMUL
diff --git a/sound/core/seq/oss/seq_oss.c b/sound/core/seq/oss/seq_oss.c
index e7234135641c..92858cf8b6eb 100644
--- a/sound/core/seq/oss/seq_oss.c
+++ b/sound/core/seq/oss/seq_oss.c
@@ -303,8 +303,7 @@ register_proc(void)
 static void
 unregister_proc(void)
 {
-        if (info_entry)
-                snd_info_unregister(info_entry);
+        snd_info_free_entry(info_entry);
         info_entry = NULL;
 }
 #endif /* CONFIG_PROC_FS */
diff --git a/sound/core/seq/seq_device.c b/sound/core/seq/seq_device.c
index 102ff548ce69..b85954e956d4 100644
--- a/sound/core/seq/seq_device.c
+++ b/sound/core/seq/seq_device.c
@@ -573,7 +573,7 @@ static void __exit alsa_seq_device_exit(void)
 {
         remove_drivers();
 #ifdef CONFIG_PROC_FS
-        snd_info_unregister(info_entry);
+        snd_info_free_entry(info_entry);
 #endif
         if (num_ops)
                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
diff --git a/sound/core/seq/seq_info.c b/sound/core/seq/seq_info.c
index 142e9e6882c9..8a7fe5cca1c9 100644
--- a/sound/core/seq/seq_info.c
+++ b/sound/core/seq/seq_info.c
@@ -64,9 +64,9 @@ int __init snd_seq_info_init(void)
 
 int __exit snd_seq_info_done(void)
 {
-        snd_info_unregister(queues_entry);
-        snd_info_unregister(clients_entry);
-        snd_info_unregister(timer_entry);
+        snd_info_free_entry(queues_entry);
+        snd_info_free_entry(clients_entry);
+        snd_info_free_entry(timer_entry);
         return 0;
 }
 #endif
diff --git a/sound/core/sound.c b/sound/core/sound.c
index 7edd1fc58b17..b4430db3fa4c 100644
--- a/sound/core/sound.c
+++ b/sound/core/sound.c
@@ -387,8 +387,7 @@ int __init snd_minor_info_init(void)
 
 int __exit snd_minor_info_done(void)
 {
-        if (snd_minor_info_entry)
-                snd_info_unregister(snd_minor_info_entry);
+        snd_info_free_entry(snd_minor_info_entry);
         return 0;
 }
 #endif /* CONFIG_PROC_FS */
diff --git a/sound/core/sound_oss.c b/sound/core/sound_oss.c
index 74f0fe5a1ba0..b2fc40aa520b 100644
--- a/sound/core/sound_oss.c
+++ b/sound/core/sound_oss.c
@@ -270,8 +270,7 @@ int __init snd_minor_info_oss_init(void)
 
 int __exit snd_minor_info_oss_done(void)
 {
-        if (snd_minor_info_oss_entry)
-                snd_info_unregister(snd_minor_info_oss_entry);
+        snd_info_free_entry(snd_minor_info_oss_entry);
         return 0;
 }
 #endif /* CONFIG_PROC_FS */
diff --git a/sound/core/timer.c b/sound/core/timer.c
index 0a984e881c10..52ecbe1e9abb 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -1126,7 +1126,7 @@ static void __init snd_timer_proc_init(void)
 
 static void __exit snd_timer_proc_done(void)
 {
-        snd_info_unregister(snd_timer_proc_entry);
+        snd_info_free_entry(snd_timer_proc_entry);
 }
 #else /* !CONFIG_PROC_FS */
 #define snd_timer_proc_init()