linux-kernel - [PATCH 21/22] UBI: Fastmap: Fix and explain duplicated PEBs

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Date:	Mon, 18 Jun 2012 18:19:04 +0200
From:	Richard Weinberger <richard@....at>
To:	linux-mtd@...ts.infradead.org
Cc:	linux-kernel@...r.kernel.org, adrian.hunter@...el.com,
	Heinz.Egger@...utronix.de, thomas.wucher@...utronix.de,
	shmulik.ladkani@...il.com, tglx@...utronix.de,
	tim.bird@...sony.com, Marius.Mazarel@...l.ro,
	artem.bityutskiy@...ux.intel.com,
	Richard Weinberger <richard@....at>
Subject: [PATCH 21/22] UBI: Fastmap: Fix and explain duplicated PEBs

Signed-off-by: Richard Weinberger <richard@....at>
---
 drivers/mtd/ubi/fastmap.c |   21 +++++++++++++++++++++
 1 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index bea9446..45f70db 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -714,6 +714,15 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
 		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 	}
 
+	/*
+	 * Sort out dups. We are allowed to have duplicates here because
+	 * the fastmap can be written without refilling all pools.
+	 * E.g. If PEB X is in a pool fastmap may detect it as empty and
+	 * puts it into the free list. But ff PEB X is in the pool, get's
+	 * used and returned (e.g. by schedule_erase()) it remains in
+	 * the erase or free list too.
+	 * We could also sort out these dups while creating the fastmap.
+	 */
 	if (list_empty(&free))
 		goto out;
 
@@ -729,6 +738,18 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
 		}
 	}
 
+	list_for_each_entry(aeb, &ai->erase, u.list) {
+		list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list) {
+			if (aeb->pnum == tmp_aeb->pnum) {
+				aeb->scrub = tmp_aeb->scrub;
+				aeb->ec = tmp_aeb->ec;
+				list_del(&tmp_aeb->u.list);
+				kfree(tmp_aeb);
+				continue;
+			}
+		}
+	}
+
 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list) {
 		list_del(&tmp_aeb->u.list);
 		list_add_tail(&tmp_aeb->u.list, &ai->free);
-- 
1.7.6.5

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