UBI: add a comment

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=beeea636030622f6de67d15c61f5b311a03d188c
Commit:     beeea636030622f6de67d15c61f5b311a03d188c
Parent:     979c9296bdcfded58ebac41905c3397317df0355
Author:     Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
AuthorDate: Tue May 20 09:54:02 2008 +0300
Committer:  Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
CommitDate: Thu Jul 24 13:32:54 2008 +0300

    UBI: add a comment
    
    It is not clear why we schedule PEB for scrubbing in case of
    -EBADMSG. Elaborate.
    
    Requested-by: Kyungmin Park <kmpark at infradead.org>
    Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
---
 drivers/mtd/ubi/vtbl.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index 3c4d68f..42a7815 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -385,7 +385,16 @@ static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
 		err = ubi_io_read_data(ubi, leb[seb->lnum], seb->pnum, 0,
 				       ubi->vtbl_size);
 		if (err == UBI_IO_BITFLIPS || err == -EBADMSG)
-			/* Scrub the PEB later */
+			/*
+			 * Scrub the PEB later. Note, -EBADMSG indicates an
+			 * uncorrectable ECC error, but we have our own CRC and
+			 * the data will be checked later. If the data is OK,
+			 * the PEB will be scrubbed (because we set
+			 * seb->scrub). If the data is not OK, the contents of
+			 * the PEB will be recovered from the second copy, and
+			 * seb->scrub will be cleared in
+			 * 'ubi_scan_add_used()'.
+			 */
 			seb->scrub = 1;
 		else if (err)
 			goto out_free;