UBI: fix eraseblock picking criteria

The 'find_wl_entry()' function expects the maximum difference as the second argument, not the maximum absolute value. So the "unknown" eraseblock picking was incorrect, as Shmulik Ladkani spotted. This patch fixes the issue. Reported-by: Shmulik Ladkani <[email protected]> Signed-off-by: Artem Bityutskiy <[email protected]> Reviewed-by: Shmulik Ladkani <[email protected]> Cc: [email protected]
redpig · Mar 9, 2012 · 7eb3aa6 · 7eb3aa6
1 parent add8287
commit 7eb3aa6
Showing 1 changed file with 4 additions and 6 deletions.
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
@@ -390,7 +390,7 @@ static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int diff)
  */
 int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
 {
-	int err, medium_ec;
+	int err;
 	struct ubi_wl_entry *e, *first, *last;
 
 	ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM ||
@@ -428,7 +428,7 @@ int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
 		 * For unknown data we pick a physical eraseblock with medium
 		 * erase counter. But we by no means can pick a physical
 		 * eraseblock with erase counter greater or equivalent than the
-		 * lowest erase counter plus %WL_FREE_MAX_DIFF.
+		 * lowest erase counter plus %WL_FREE_MAX_DIFF/2.
 		 */
 		first = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry,
 					u.rb);
@@ -437,10 +437,8 @@ int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
 		if (last->ec - first->ec < WL_FREE_MAX_DIFF)
 			e = rb_entry(ubi->free.rb_node,
 					struct ubi_wl_entry, u.rb);
-		else {
-			medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2;
-			e = find_wl_entry(&ubi->free, medium_ec);
-		}
+		else
+			e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF/2);
 		break;
 	case UBI_SHORTTERM:
 		/*