linux-kernel - [PATCH] mtd, ubi: set free_count to zero before walking through erase list

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Message-Id: <1461319598-17157-1-git-send-email-hs@denx.de>
Date:	Fri, 22 Apr 2016 12:06:38 +0200
From:	Heiko Schocher <hs@...x.de>
To:	linux-mtd@...ts.infradead.org
Cc:	Heiko Schocher <hs@...x.de>,
	Richard Weinberger <richard.weinberger@...il.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	linux-kernel@...r.kernel.org,
	Brian Norris <computersforpeace@...il.com>,
	Richard Weinberger <richard@....at>,
	David Woodhouse <dwmw2@...radead.org>,
	Artem Bityutskiy <dedekind1@...il.com>
Subject: [PATCH] mtd, ubi: set free_count to zero before walking through erase list

Set free_count to zero before walking through ai->erase list
in wl_init().

Found in U-Boot as U-Boot has no workqueue/threads, it immediately
calls erase_worker(), which increase for each erased block
free_count. Without this patch, free_count gets after
this initialized to zero in wl_init(), so the free_count
variable always has the maybe wrong value 0 in U-Boot.

Signed-off-by: Heiko Schocher <hs@...x.de>
Reviewed-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
---
Detected this behaviour on the dxr2 board, where the
UBI fastmap gets not written when attaching/dettaching
on an empty NAND. It drops instead the error message:

could not find any anchor PEB

With this patch, fastmap gets written on dettach.

corresponding U-Boot Thread:
http://lists.denx.de/pipermail/u-boot/2016-April/252338.html

 drivers/mtd/ubi/wl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 17ec948..959c7b12 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -1534,6 +1534,7 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
 		INIT_LIST_HEAD(&ubi->pq[i]);
 	ubi->pq_head = 0;
 
+	ubi->free_count = 0;
 	list_for_each_entry_safe(aeb, tmp, &ai->erase, u.list) {
 		cond_resched();
 
@@ -1552,7 +1553,6 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
 		found_pebs++;
 	}
 
-	ubi->free_count = 0;
 	list_for_each_entry(aeb, &ai->free, u.list) {
 		cond_resched();
 
-- 
2.5.0