[PATCH 2/7] ide: IDE settings don't need an ide_lock held

[Bartlomiej Zolnierkiewicz]

From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Subject: [PATCH] ide: IDE settings don't need an ide_lock held

IDE settings are protected by ide_setting_mtx mutex so there is
no need to hold ide_lock in ide_setting_ioctl(), ide_read_setting()
and ide_proc_unregister_driver().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
---
 drivers/ide/ide-ioctls.c |    3 ---
 drivers/ide/ide-proc.c   |   25 ++++---------------------
 2 files changed, 4 insertions(+), 24 deletions(-)

Index: b/drivers/ide/ide-ioctls.c
===================================================================
--- a/drivers/ide/ide-ioctls.c
+++ b/drivers/ide/ide-ioctls.c
@@ -19,7 +19,6 @@ int ide_setting_ioctl(ide_drive_t *drive
 		      const struct ide_ioctl_devset *s)
 {
 	const struct ide_devset *ds;
-	unsigned long flags;
 	int err = -EOPNOTSUPP;
 
 	for (; (ds = s->setting); s++) {
@@ -33,9 +32,7 @@ int ide_setting_ioctl(ide_drive_t *drive
 
 read_val:
 	mutex_lock(&ide_setting_mtx);
-	spin_lock_irqsave(&ide_lock, flags);
 	err = ds->get(drive);
-	spin_unlock_irqrestore(&ide_lock, flags);
 	mutex_unlock(&ide_setting_mtx);
 	return err >= 0 ? put_user(err, (long __user *)arg) : err;
 
Index: b/drivers/ide/ide-proc.c
===================================================================
--- a/drivers/ide/ide-proc.c
+++ b/drivers/ide/ide-proc.c
@@ -155,13 +155,8 @@ static int ide_read_setting(ide_drive_t 
 	const struct ide_devset *ds = setting->setting;
 	int val = -EINVAL;
 
-	if (ds->get) {
-		unsigned long flags;
-
-		spin_lock_irqsave(&ide_lock, flags);
+	if (ds->get)
 		val = ds->get(drive);
-		spin_unlock_irqrestore(&ide_lock, flags);
-	}
 
 	return val;
 }
@@ -583,31 +578,19 @@ EXPORT_SYMBOL(ide_proc_register_driver);
  *	Clean up the driver specific /proc files and IDE settings
  *	for a given drive.
  *
- *	Takes ide_setting_mtx and ide_lock.
- *	Caller must hold none of the locks.
+ *	Takes ide_setting_mtx.
  */
 
 void ide_proc_unregister_driver(ide_drive_t *drive, ide_driver_t *driver)
 {
-	unsigned long flags;
-
 	ide_remove_proc_entries(drive->proc, driver->proc_entries(drive));
 
 	mutex_lock(&ide_setting_mtx);
-	spin_lock_irqsave(&ide_lock, flags);
 	/*
-	 * ide_setting_mtx 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_mtx.
+	 * ide_setting_mtx protects both the settings list and the use
+	 * of settings (we cannot take a setting out that is being used).
 	 */
 	drive->settings = NULL;
-	spin_unlock_irqrestore(&ide_lock, flags);
 	mutex_unlock(&ide_setting_mtx);
 }
 EXPORT_SYMBOL(ide_proc_unregister_driver);
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