linux-kernel - [PATCH 1/2] mtd: nand: ecc-bch: Fix the double counting of ECC stat

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Date:   Tue, 11 May 2021 09:40:34 +0800
From:   YouChing Lin <ycllin@...c.com.tw>
To:     miquel.raynal@...tlin.com, richard@....at, vigneshr@...com
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        juliensu@...c.com.tw, YouChing Lin <ycllin@...c.com.tw>
Subject: [PATCH 1/2] mtd: nand: ecc-bch: Fix the double counting of ECC stat

If you use SPI-NAND with SW-ECC engine, the ECC related statistics
(ecc_stats.failed & ecc_stats.corrected) will be doubled, because
those numbers will be double-counted in ecc-sw-bch.c and
drivers/mtd/nand/spi/core.c.

This can be found by using nandtest/nandbiterrs validation.

Signed-off-by: YouChing Lin <ycllin@...c.com.tw>
---
 drivers/mtd/nand/ecc-sw-bch.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/ecc-sw-bch.c b/drivers/mtd/nand/ecc-sw-bch.c
index 405552d..aade381 100644
--- a/drivers/mtd/nand/ecc-sw-bch.c
+++ b/drivers/mtd/nand/ecc-sw-bch.c
@@ -372,11 +372,12 @@ static int nand_ecc_sw_bch_finish_io_req(struct nand_device *nand,
 						    &ecccode[i],
 						    &ecccalc[i]);
 		if (stat < 0) {
-			mtd->ecc_stats.failed++;
-		} else {
-			mtd->ecc_stats.corrected += stat;
-			max_bitflips = max_t(unsigned int, max_bitflips, stat);
+			nand_ecc_restore_req(&engine_conf->req_ctx, req);
+
+			return -EBADMSG;
 		}
+
+		max_bitflips = max_t(unsigned int, max_bitflips, stat);
 	}
 
 	nand_ecc_restore_req(&engine_conf->req_ctx, req);
-- 
1.9.1