mtd: nand: relax ecc.read_page() return value for uncorrectable ECC

The comment for ecc.read_page() requires that it should return
"0 if bitflips uncorrectable".

Actually, drivers could return positive values when uncorrectable
bitflips occur.  For example, nand_read_page_swecc() is the case.
If ecc.correct() returns -EBADMSG for the first ECC sector, and
a positive value for the second one, nand_read_page_swecc() returns
a positive max_bitflips and increments ecc_stats.failed for the same
page.

The requirement can be relaxed by tweaking nand_do_read_ops().
Move the max_bitflips calculation below the retry.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 36258e69a389..de6c8045c85b 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1993,8 +1993,6 @@ read_retry:
                                 break;
                         }
 
-                        max_bitflips = max_t(unsigned int, max_bitflips, ret);
-
                         /* Transfer not aligned data */
                         if (use_bufpoi) {
                                 if (!NAND_HAS_SUBPAGE_READ(chip) && !oob &&
@@ -2045,6 +2043,7 @@ read_retry:
                         }
 
                         buf += bytes;
+                        max_bitflips = max_t(unsigned int, max_bitflips, ret);
                 } else {
                         memcpy(buf, chip->buffers->databuf + col, bytes);
                         buf += bytes;