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authorKevin Cernekee <kpc.mtd@gmail.com>2009-06-09 10:59:19 -0700
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2009-06-10 16:50:50 +0300
commitd9dd0887cc5c6df0dbbe5a307284610607eea7ab (patch)
tree1b6dc1bf5e90c6cd49896196abda9369a50ab3b2 /drivers/mtd/ubi/build.c
parent6b5c94c6b4e1630a8e1ee7d30383d9396603749f (diff)
UBI: add reboot notifier
Terminate the UBI background thread prior to restarting the system. [Artem: amended comments a little] Signed-off-by: Kevin Cernekee <kpc.mtd@gmail.com> Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'drivers/mtd/ubi/build.c')
-rw-r--r--drivers/mtd/ubi/build.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 964a99d48bc..286ed594e5a 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -41,6 +41,7 @@
#include <linux/miscdevice.h>
#include <linux/log2.h>
#include <linux/kthread.h>
+#include <linux/reboot.h>
#include "ubi.h"
/* Maximum length of the 'mtd=' parameter */
@@ -823,6 +824,34 @@ static int autoresize(struct ubi_device *ubi, int vol_id)
}
/**
+ * ubi_reboot_notifier - halt UBI transactions immediately prior to a reboot.
+ * @n: reboot notifier object
+ * @state: SYS_RESTART, SYS_HALT, or SYS_POWER_OFF
+ * @cmd: pointer to command string for RESTART2
+ *
+ * This function stops the UBI background thread so that the flash device
+ * remains quiescent when Linux restarts the system. Any queued work will be
+ * discarded, but this function will block until do_work() finishes if an
+ * operation is already in progress.
+ *
+ * This function solves a real-life problem observed on NOR flashes when an
+ * PEB erase operation starts, then the system is rebooted before the erase is
+ * finishes, and the boot loader gets confused and dies. So we prefer to finish
+ * the ongoing operation before rebooting.
+ */
+static int ubi_reboot_notifier(struct notifier_block *n, unsigned long state,
+ void *cmd)
+{
+ struct ubi_device *ubi;
+
+ ubi = container_of(n, struct ubi_device, reboot_notifier);
+ if (ubi->bgt_thread)
+ kthread_stop(ubi->bgt_thread);
+ ubi_sync(ubi->ubi_num);
+ return NOTIFY_DONE;
+}
+
+/**
* ubi_attach_mtd_dev - attach an MTD device.
* @mtd: MTD device description object
* @ubi_num: number to assign to the new UBI device
@@ -978,6 +1007,11 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
wake_up_process(ubi->bgt_thread);
spin_unlock(&ubi->wl_lock);
+ /* Flash device priority is 0 - UBI needs to shut down first */
+ ubi->reboot_notifier.priority = 1;
+ ubi->reboot_notifier.notifier_call = ubi_reboot_notifier;
+ register_reboot_notifier(&ubi->reboot_notifier);
+
ubi_devices[ubi_num] = ubi;
ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
return ubi_num;
@@ -1049,6 +1083,7 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
* Before freeing anything, we have to stop the background thread to
* prevent it from doing anything on this device while we are freeing.
*/
+ unregister_reboot_notifier(&ubi->reboot_notifier);
if (ubi->bgt_thread)
kthread_stop(ubi->bgt_thread);