Merge branch 'drm-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...

[pandora-kernel.git] / drivers / ide / ide.c

diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 287a662..1689076 100644 (file)
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -973,8 +973,8 @@ ide_settings_t *ide_find_setting_by_name (ide_drive_t *drive, char *name)
  *     @drive: drive
  *
  *     Automatically remove all the driver specific settings for this
- *     drive. This function may sleep and must not be called from IRQ
- *     context. The caller must hold ide_setting_sem.
+ *     drive. This function may not be called from IRQ context. The
+ *     caller must hold ide_setting_sem.
  */
  
 static void auto_remove_settings (ide_drive_t *drive)
@@ -1874,11 +1874,22 @@ void ide_unregister_subdriver(ide_drive_t *drive, ide_driver_t *driver)
 {
        unsigned long flags;
        
-       down(&ide_setting_sem);
-       spin_lock_irqsave(&ide_lock, flags);
 #ifdef CONFIG_PROC_FS
        ide_remove_proc_entries(drive->proc, driver->proc);
 #endif
+       down(&ide_setting_sem);
+       spin_lock_irqsave(&ide_lock, flags);
+       /*
+        * ide_setting_sem protects the settings list
+        * ide_lock protects the use of settings
+        *
+        * so we need to hold both, ide_settings_sem because we want to
+        * modify the settings list, and ide_lock because we cannot take
+        * a setting out that is being used.
+        *
+        * OTOH both ide_{read,write}_setting are only ever used under
+        * ide_setting_sem.
+        */
        auto_remove_settings(drive);
        spin_unlock_irqrestore(&ide_lock, flags);
        up(&ide_setting_sem);