1 files changed, 15 insertions, 4 deletions

diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 287a66201150..16890769dca6 100644
--- 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);