vserver 1.9.5.x5

[linux-2.6.git] / sound / core / seq / seq_device.c

diff --git a/sound/core/seq/seq_device.c b/sound/core/seq/seq_device.c
index 0545ff8..4d80f39 100644 (file)
--- a/sound/core/seq/seq_device.c
+++ b/sound/core/seq/seq_device.c
@@ -41,6 +41,7 @@
 #include <sound/core.h>
 #include <sound/info.h>
 #include <sound/seq_device.h>
+#include <sound/seq_kernel.h>
 #include <sound/initval.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
@@ -125,11 +126,31 @@ static void snd_seq_device_info(snd_info_entry_t *entry, snd_info_buffer_t * buf
  * load all registered drivers (called from seq_clientmgr.c)
  */
 
+#ifdef CONFIG_KMOD
+/* avoid auto-loading during module_init() */
+static int snd_seq_in_init;
+void snd_seq_autoload_lock(void)
+{
+       snd_seq_in_init++;
+}
+
+void snd_seq_autoload_unlock(void)
+{
+       snd_seq_in_init--;
+}
+#endif
+
 void snd_seq_device_load_drivers(void)
 {
 #ifdef CONFIG_KMOD
        struct list_head *head;
 
+       /* Calling request_module during module_init()
+        * may cause blocking.
+        */
+       if (snd_seq_in_init)
+               return;
+
        if (! current->fs->root)
                return;
 
@@ -309,12 +330,16 @@ int snd_seq_device_register_driver(char *id, snd_seq_dev_ops_t *entry, int argsi
            entry->init_device == NULL || entry->free_device == NULL)
                return -EINVAL;
 
+       snd_seq_autoload_lock();
        ops = find_driver(id, 1);
-       if (ops == NULL)
+       if (ops == NULL) {
+               snd_seq_autoload_unlock();
                return -ENOMEM;
+       }
        if (ops->driver & DRIVER_LOADED) {
                snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
                unlock_driver(ops);
+               snd_seq_autoload_unlock();
                return -EBUSY;
        }
 
@@ -332,6 +357,7 @@ int snd_seq_device_register_driver(char *id, snd_seq_dev_ops_t *entry, int argsi
        up(&ops->reg_mutex);
 
        unlock_driver(ops);
+       snd_seq_autoload_unlock();
 
        return 0;
 }
@@ -543,3 +569,7 @@ EXPORT_SYMBOL(snd_seq_device_load_drivers);
 EXPORT_SYMBOL(snd_seq_device_new);
 EXPORT_SYMBOL(snd_seq_device_register_driver);
 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
+#ifdef CONFIG_KMOD
+EXPORT_SYMBOL(snd_seq_autoload_lock);
+EXPORT_SYMBOL(snd_seq_autoload_unlock);
+#endif