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authorArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2012-06-07 15:15:30 +0300
committerArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2012-06-07 15:22:21 +0300
commit12027f1b3fd69a4e9017e6b13c72547a99c6cf54 (patch)
tree19b7b41b12f4c1eb0a0efdbd494c58e2381e1dd9
parent818039c7d597db3b1d30964a8f9489ac42c0642d (diff)
downloadop-kernel-dev-12027f1b3fd69a4e9017e6b13c72547a99c6cf54.zip
op-kernel-dev-12027f1b3fd69a4e9017e6b13c72547a99c6cf54.tar.gz
UBI: correct ubi_wl_flush locking
Commit "62f38455 UBI: modify ubi_wl_flush function to clear work queue for a lnum" takes the 'work_sem' semaphore in write mode for the entire loop, which is not very good because it will block other workers for potentially long time. We do not need to have it in write mode - read mode is enough, and we do not need to hole it over the entire loop. So this patch turns changes the locking: takes 'work_sem' in read mode and pushes it down to the loop. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
-rw-r--r--drivers/mtd/ubi/wl.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 9df100a..b6be644 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -1262,11 +1262,11 @@ int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
dbg_wl("flush pending work for LEB %d:%d (%d pending works)",
vol_id, lnum, ubi->works_count);
- down_write(&ubi->work_sem);
while (found) {
struct ubi_work *wrk;
found = 0;
+ down_read(&ubi->work_sem);
spin_lock(&ubi->wl_lock);
list_for_each_entry(wrk, &ubi->works, list) {
if ((vol_id == UBI_ALL || wrk->vol_id == vol_id) &&
@@ -1277,18 +1277,27 @@ int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
spin_unlock(&ubi->wl_lock);
err = wrk->func(ubi, wrk, 0);
- if (err)
- goto out;
+ if (err) {
+ up_read(&ubi->work_sem);
+ return err;
+ }
+
spin_lock(&ubi->wl_lock);
found = 1;
break;
}
}
spin_unlock(&ubi->wl_lock);
+ up_read(&ubi->work_sem);
}
-out:
+ /*
+ * Make sure all the works which have been done in parallel are
+ * finished.
+ */
+ down_write(&ubi->work_sem);
up_write(&ubi->work_sem);
+
return err;
}
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