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Subject[PATCH 2/7] ide: IDE settings don't need an ide_lock held
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
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@gmail.com>
---
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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