[ALSA] dynamic minors (3/6): store device-specific object pointers dynamically

Instead of storing the pointers to the device-specific structures in an
array, put them into the struct snd_minor, and look them up dynamically.

This makes the device type modules independent of the minor number
encoding.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

1 files changed, 42 insertions, 49 deletions

diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
index 27d5bf7266f0..b8c0c8c4d126 100644
--- a/sound/core/hwdep.c
+++ b/sound/core/hwdep.c
@@ -35,8 +35,7 @@ MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
 MODULE_DESCRIPTION("Hardware dependent layer");
 MODULE_LICENSE("GPL");
 
-static struct snd_hwdep *snd_hwdep_devices[SNDRV_CARDS * SNDRV_MINOR_HWDEPS];
-
+static LIST_HEAD(snd_hwdep_devices);
 static DECLARE_MUTEX(register_mutex);
 
 static int snd_hwdep_free(struct snd_hwdep *hwdep);
@@ -44,9 +43,19 @@ static int snd_hwdep_dev_free(struct snd_device *device);
 static int snd_hwdep_dev_register(struct snd_device *device);
 static int snd_hwdep_dev_unregister(struct snd_device *device);
 
-/*
 
- */
+static struct snd_hwdep *snd_hwdep_search(struct snd_card *card, int device)
+{
+        struct list_head *p;
+        struct snd_hwdep *hwdep;
+
+        list_for_each(p, &snd_hwdep_devices) {
+                hwdep = list_entry(p, struct snd_hwdep, list);
+                if (hwdep->card == card && hwdep->device == device)
+                        return hwdep;
+        }
+        return NULL;
+}
 
 static loff_t snd_hwdep_llseek(struct file * file, loff_t offset, int orig)
 {
@@ -77,34 +86,25 @@ static ssize_t snd_hwdep_write(struct file * file, const char __user *buf,
 static int snd_hwdep_open(struct inode *inode, struct file * file)
 {
         int major = imajor(inode);
-        int cardnum;
-        int device;
         struct snd_hwdep *hw;
         int err;
         wait_queue_t wait;
 
         if (major == snd_major) {
-                cardnum = SNDRV_MINOR_CARD(iminor(inode));
-                device = SNDRV_MINOR_DEVICE(iminor(inode)) - SNDRV_MINOR_HWDEP;
+                hw = snd_lookup_minor_data(iminor(inode),
+                                           SNDRV_DEVICE_TYPE_HWDEP);
 #ifdef CONFIG_SND_OSSEMUL
         } else if (major == SOUND_MAJOR) {
-                cardnum = SNDRV_MINOR_OSS_CARD(iminor(inode));
-                device = 0;
+                hw = snd_lookup_oss_minor_data(iminor(inode),
+                                               SNDRV_OSS_DEVICE_TYPE_DMFM);
 #endif
         } else
                 return -ENXIO;
-        cardnum %= SNDRV_CARDS;
-        device %= SNDRV_MINOR_HWDEPS;
-        hw = snd_hwdep_devices[(cardnum * SNDRV_MINOR_HWDEPS) + device];
         if (hw == NULL)
                 return -ENODEV;
 
         if (!hw->ops.open)
                 return -ENXIO;
-#ifdef CONFIG_SND_OSSEMUL
-        if (major == SOUND_MAJOR && hw->oss_type < 0)
-                return -ENXIO;
-#endif
 
         if (!try_module_get(hw->card->module))
                 return -EFAULT;
@@ -265,9 +265,6 @@ static int snd_hwdep_control_ioctl(struct snd_card *card,
                                    struct snd_ctl_file * control,
                                    unsigned int cmd, unsigned long arg)
 {
-        unsigned int tmp;
-        
-        tmp = card->number * SNDRV_MINOR_HWDEPS;
         switch (cmd) {
         case SNDRV_CTL_IOCTL_HWDEP_NEXT_DEVICE:
                 {
@@ -275,14 +272,16 @@ static int snd_hwdep_control_ioctl(struct snd_card *card,
 
                         if (get_user(device, (int __user *)arg))
                                 return -EFAULT;
+                        down(&register_mutex);
                         device = device < 0 ? 0 : device + 1;
                         while (device < SNDRV_MINOR_HWDEPS) {
-                                if (snd_hwdep_devices[tmp + device])
+                                if (snd_hwdep_search(card, device))
                                         break;
                                 device++;
                         }
                         if (device >= SNDRV_MINOR_HWDEPS)
                                 device = -1;
+                        up(&register_mutex);
                         if (put_user(device, (int __user *)arg))
                                 return -EFAULT;
                         return 0;
@@ -290,17 +289,19 @@ static int snd_hwdep_control_ioctl(struct snd_card *card,
         case SNDRV_CTL_IOCTL_HWDEP_INFO:
                 {
                         struct snd_hwdep_info __user *info = (struct snd_hwdep_info __user *)arg;
-                        int device;
+                        int device, err;
                         struct snd_hwdep *hwdep;
 
                         if (get_user(device, &info->device))
                                 return -EFAULT;
-                        if (device < 0 || device >= SNDRV_MINOR_HWDEPS)
-                                return -ENXIO;
-                        hwdep = snd_hwdep_devices[tmp + device];
-                        if (hwdep == NULL)
-                                return -ENXIO;
-                        return snd_hwdep_info(hwdep, info);
+                        down(&register_mutex);
+                        hwdep = snd_hwdep_search(card, device);
+                        if (hwdep)
+                                err = snd_hwdep_info(hwdep, info);
+                        else
+                                err = -ENXIO;
+                        up(&register_mutex);
+                        return err;
                 }
         }
         return -ENOIOCTLCMD;
@@ -397,23 +398,22 @@ static int snd_hwdep_dev_free(struct snd_device *device)
 static int snd_hwdep_dev_register(struct snd_device *device)
 {
         struct snd_hwdep *hwdep = device->device_data;
-        int idx, err;
+        int err;
         char name[32];
 
         down(&register_mutex);
-        idx = (hwdep->card->number * SNDRV_MINOR_HWDEPS) + hwdep->device;
-        if (snd_hwdep_devices[idx]) {
+        if (snd_hwdep_search(hwdep->card, hwdep->device)) {
                 up(&register_mutex);
                 return -EBUSY;
         }
-        snd_hwdep_devices[idx] = hwdep;
+        list_add_tail(&hwdep->list, &snd_hwdep_devices);
         sprintf(name, "hwC%iD%i", hwdep->card->number, hwdep->device);
         if ((err = snd_register_device(SNDRV_DEVICE_TYPE_HWDEP,
                                        hwdep->card, hwdep->device,
-                                       &snd_hwdep_f_ops, name)) < 0) {
+                                       &snd_hwdep_f_ops, hwdep, name)) < 0) {
                 snd_printk(KERN_ERR "unable to register hardware dependent device %i:%i\n",
                            hwdep->card->number, hwdep->device);
-                snd_hwdep_devices[idx] = NULL;
+                list_del(&hwdep->list);
                 up(&register_mutex);
                 return err;
         }
@@ -425,7 +425,7 @@ static int snd_hwdep_dev_register(struct snd_device *device)
                 } else {
                         if (snd_register_oss_device(hwdep->oss_type,
                                                     hwdep->card, hwdep->device,
-                                                    &snd_hwdep_f_ops,
+                                                    &snd_hwdep_f_ops, hwdep,
                                                     hwdep->oss_dev) < 0) {
                                 snd_printk(KERN_ERR "unable to register OSS compatibility device %i:%i\n",
                                            hwdep->card->number, hwdep->device);
@@ -441,12 +441,10 @@ static int snd_hwdep_dev_register(struct snd_device *device)
 static int snd_hwdep_dev_unregister(struct snd_device *device)
 {
         struct snd_hwdep *hwdep = device->device_data;
-        int idx;
 
         snd_assert(hwdep != NULL, return -ENXIO);
         down(&register_mutex);
-        idx = (hwdep->card->number * SNDRV_MINOR_HWDEPS) + hwdep->device;
-        if (snd_hwdep_devices[idx] != hwdep) {
+        if (snd_hwdep_search(hwdep->card, hwdep->device) != hwdep) {
                 up(&register_mutex);
                 return -EINVAL;
         }
@@ -455,7 +453,7 @@ static int snd_hwdep_dev_unregister(struct snd_device *device)
                 snd_unregister_oss_device(hwdep->oss_type, hwdep->card, hwdep->device);
 #endif
         snd_unregister_device(SNDRV_DEVICE_TYPE_HWDEP, hwdep->card, hwdep->device);
-        snd_hwdep_devices[idx] = NULL;
+        list_del(&hwdep->list);
         up(&register_mutex);
         return snd_hwdep_free(hwdep);
 }
@@ -467,18 +465,14 @@ static int snd_hwdep_dev_unregister(struct snd_device *device)
 static void snd_hwdep_proc_read(struct snd_info_entry *entry,
                                 struct snd_info_buffer *buffer)
 {
-        int idx;
+        struct list_head *p;
         struct snd_hwdep *hwdep;
 
         down(&register_mutex);
-        for (idx = 0; idx < SNDRV_CARDS * SNDRV_MINOR_HWDEPS; idx++) {
-                hwdep = snd_hwdep_devices[idx];
-                if (hwdep == NULL)
-                        continue;
+        list_for_each(p, &snd_hwdep_devices) {
+                hwdep = list_entry(p, struct snd_hwdep, list);
                 snd_iprintf(buffer, "%02i-%02i: %s\n",
-                                        idx / SNDRV_MINOR_HWDEPS,
-                                        idx % SNDRV_MINOR_HWDEPS,
-                                        hwdep->name);
+                            hwdep->card->number, hwdep->device, hwdep->name);
         }
         up(&register_mutex);
 }
@@ -493,9 +487,8 @@ static int __init alsa_hwdep_init(void)
 {
         struct snd_info_entry *entry;
 
-        memset(snd_hwdep_devices, 0, sizeof(snd_hwdep_devices));
         if ((entry = snd_info_create_module_entry(THIS_MODULE, "hwdep", NULL)) != NULL) {
-                entry->c.text.read_size = 512;
+                entry->c.text.read_size = PAGE_SIZE;
                 entry->c.text.read = snd_hwdep_proc_read;
                 if (snd_info_register(entry) < 0) {
                         snd_info_free_entry(entry);