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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2007-12-18 15:54:35 +0200
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2007-12-26 19:15:16 +0200
commit593dd33c92c6529443d5df1350dc5cc76511232d (patch)
treedda360da5a5f66eb36b55a4c2e8eb985e997ffd6 /drivers/mtd/ubi
parent458dbb3d07574e8fcdcb921ac155ccd81b16b05f (diff)
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: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'drivers/mtd/ubi')
-rw-r--r--drivers/mtd/ubi/ubi.h1
-rw-r--r--drivers/mtd/ubi/wl.c39
2 files changed, 33 insertions, 7 deletions
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index ea9a6990a4d..994233d6e1e 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -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;
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index a60f9425ab1..8421c7a9a83 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -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 @@ retry:
* 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 @@ retry:
*/
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);