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Commit 593dd33c authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

UBI: fix ubi_wl_flush 



The flush function should finish all the pending jobs. But if
somebody else is doing a work, this function should wait and let
it finish.

This patche uses rw semaphore for synchronization purpose - it
just looks quite convinient.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 458dbb3d

drivers/mtd/ubi/ubi.h

+1 −0
Original line number Diff line number Diff line
@@ -355,6 +355,7 @@ struct ubi_device { 
	} prot;

	spinlock_t wl_lock;

	struct mutex move_mutex;

	struct rw_semaphore work_sem;

	int wl_scheduled;

	struct ubi_wl_entry **lookuptbl;

	unsigned long long abs_ec;

drivers/mtd/ubi/wl.c

+32 −7
Original line number Diff line number Diff line
@@ -251,10 +251,18 @@ static int do_work(struct ubi_device *ubi) 


	cond_resched();



	/*

	 * @ubi->work_sem is used to synchronize with the workers. Workers take

	 * it in read mode, so many of them may be doing works at a time. But

	 * the queue flush code has to be sure the whole queue of works is

	 * done, and it takes the mutex in write mode.

	 */

	down_read(&ubi->work_sem);

	spin_lock(&ubi->wl_lock);



	if (list_empty(&ubi->works)) {

		spin_unlock(&ubi->wl_lock);

		up_read(&ubi->work_sem);

		return 0;

	}
@@ -275,6 +283,7 @@ static int do_work(struct ubi_device *ubi) 
	ubi->works_count -= 1;

	ubi_assert(ubi->works_count >= 0);

	spin_unlock(&ubi->wl_lock);

	up_read(&ubi->work_sem);

	return err;

}
@@ -1173,7 +1182,7 @@ int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture) 
		 * the WL unit has not put the PEB to the "used" tree yet, but

		 * it is about to do this. So we just set a flag which will

		 * tell the WL worker that the PEB is not needed anymore and

		 * should be sheduled for erasure.

		 * should be scheduled for erasure.

		 */

		dbg_wl("PEB %d is the target of data moving", pnum);

		ubi_assert(!ubi->move_to_put);
@@ -1280,17 +1289,32 @@ int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum) 
 */

int ubi_wl_flush(struct ubi_device *ubi)

{

	int err, pending_count;



	pending_count = ubi->works_count;



	dbg_wl("flush (%d pending works)", pending_count);

	int err;



	/*

	 * Erase while the pending works queue is not empty, but not more then

	 * the number of currently pending works.

	 */

	while (pending_count-- > 0) {

	dbg_wl("flush (%d pending works)", ubi->works_count);

	while (ubi->works_count) {

		err = do_work(ubi);

		if (err)

			return err;

	}



	/*

	 * Make sure all the works which have been done in parallel are

	 * finished.

	 */

	down_write(&ubi->work_sem);

	up_write(&ubi->work_sem);



	/*

	 * And in case last was the WL worker and it cancelled the LEB

	 * movement, flush again.

	 */

	while (ubi->works_count) {

		dbg_wl("flush more (%d pending works)", ubi->works_count);

		err = do_work(ubi);

		if (err)

			return err;
@@ -1426,6 +1450,7 @@ int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si) 
	ubi->prot.pnum = ubi->prot.aec = RB_ROOT;

	spin_lock_init(&ubi->wl_lock);

	mutex_init(&ubi->move_mutex);

	init_rwsem(&ubi->work_sem);

	ubi->max_ec = si->max_ec;

	INIT_LIST_HEAD(&ubi->works);