[MTD] NAND Signal that a bitflip was corrected by ECC
Return -EUCLEAN on read when a bitflip was detected and corrected, so the
clients can react and eventually copy the affected block to a spare one.
Make all in kernel users aware of the change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/mtd/inftlcore.c b/drivers/mtd/inftlcore.c
index efb1a95..1e21a2c 100644
--- a/drivers/mtd/inftlcore.c
+++ b/drivers/mtd/inftlcore.c
@@ -355,7 +355,7 @@
ret = mtd->read(mtd, (inftl->EraseSize * BlockMap[block]) +
(block * SECTORSIZE), SECTORSIZE, &retlen,
movebuf);
- if (ret < 0) {
+ if (ret < 0 && ret != -EUCLEAN) {
ret = mtd->read(mtd,
(inftl->EraseSize * BlockMap[block]) +
(block * SECTORSIZE), SECTORSIZE,
@@ -922,7 +922,10 @@
} else {
size_t retlen;
loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
- if (mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer))
+ int ret = mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer);
+
+ /* Handle corrected bit flips gracefully */
+ if (ret < 0 && ret != -EUCLEAN)
return -EIO;
}
return 0;
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 7522fc3..a48210d 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -199,10 +199,13 @@
/* Nand returns -EBADMSG on ecc errors, but it returns
* the data. For our userspace tools it is important
* to dump areas with ecc errors !
+ * For kernel internal usage it also might return -EUCLEAN
+ * to signal the caller that a bitflip has occured and has
+ * been corrected by the ECC algorithm.
* Userspace software which accesses NAND this way
* must be aware of the fact that it deals with NAND
*/
- if (!ret || (ret == -EBADMSG)) {
+ if (!ret || (ret == -EUCLEAN) || (ret == -EBADMSG)) {
*ppos += retlen;
if (copy_to_user(buf, kbuf, retlen)) {
kfree(kbuf);
diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index 38151b8..3c8d5e6 100644
--- a/drivers/mtd/mtdconcat.c
+++ b/drivers/mtd/mtdconcat.c
@@ -56,7 +56,7 @@
size_t * retlen, u_char * buf)
{
struct mtd_concat *concat = CONCAT(mtd);
- int err = -EINVAL;
+ int ret = 0, err = -EINVAL;
int i;
*retlen = 0;
@@ -80,9 +80,18 @@
err = subdev->read(subdev, from, size, &retsize, buf);
- if (err)
+ if (err && (err != -EBADMSG) && (err != -EUCLEAN))
break;
+ /* Save information about bitflips! */
+ if (err) {
+ if (err == -EBADMSG)
+ ret = err;
+ else if (!ret)
+ ret = err;
+ err = 0;
+ }
+
*retlen += retsize;
len -= size;
if (len == 0)
@@ -92,7 +101,7 @@
buf += size;
from = 0;
}
- return err;
+ return err ? err : ret;
}
static int
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index b8e6e15..7a3a449 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1035,7 +1035,10 @@
if (ret)
return ret;
- return mtd->ecc_stats.failed - stats.failed ? -EBADMSG : 0;
+ if (mtd->ecc_stats.failed - stats.failed)
+ return -EBADMSG;
+
+ return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
}
/**
diff --git a/drivers/mtd/nftlcore.c b/drivers/mtd/nftlcore.c
index f6ffe79..dc75735 100644
--- a/drivers/mtd/nftlcore.c
+++ b/drivers/mtd/nftlcore.c
@@ -422,7 +422,7 @@
ret = mtd->read(mtd, (nftl->EraseSize * BlockMap[block]) + (block * 512),
512, &retlen, movebuf);
- if (ret < 0) {
+ if (ret < 0 && ret != -EUCLEAN) {
ret = mtd->read(mtd, (nftl->EraseSize * BlockMap[block])
+ (block * 512), 512, &retlen,
movebuf);
@@ -768,7 +768,9 @@
} else {
loff_t ptr = (lastgoodEUN * nftl->EraseSize) + blockofs;
size_t retlen;
- if (mtd->read(mtd, ptr, 512, &retlen, buffer))
+ int res = mtd->read(mtd, ptr, 512, &retlen, buffer);
+
+ if (res < 0 && res != -EUCLEAN)
return -EIO;
}
return 0;
diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c
index 1195d06d..a7f153f 100644
--- a/fs/jffs2/wbuf.c
+++ b/fs/jffs2/wbuf.c
@@ -296,10 +296,11 @@
/* Do the read... */
ret = c->mtd->read(c->mtd, start, c->wbuf_ofs - start, &retlen, buf);
- if (ret == -EBADMSG && retlen == c->wbuf_ofs - start) {
- /* ECC recovered */
+ /* ECC recovered ? */
+ if ((ret == -EUCLEAN || ret == -EBADMSG) &&
+ (retlen == c->wbuf_ofs - start))
ret = 0;
- }
+
if (ret || retlen != c->wbuf_ofs - start) {
printk(KERN_CRIT "Old data are already lost in wbuf recovery. Data loss ensues.\n");
@@ -908,20 +909,21 @@
down_read(&c->wbuf_sem);
ret = c->mtd->read(c->mtd, ofs, len, retlen, buf);
- if ( (ret == -EBADMSG) && (*retlen == len) ) {
- printk(KERN_WARNING "mtd->read(0x%zx bytes from 0x%llx) returned ECC error\n",
- len, ofs);
+ if ( (ret == -EBADMSG || ret == -EUCLEAN) && (*retlen == len) ) {
+ if (ret == -EBADMSG)
+ printk(KERN_WARNING "mtd->read(0x%zx bytes from 0x%llx)"
+ " returned ECC error\n", len, ofs);
/*
- * We have the raw data without ECC correction in the buffer, maybe
- * we are lucky and all data or parts are correct. We check the node.
- * If data are corrupted node check will sort it out.
- * We keep this block, it will fail on write or erase and the we
- * mark it bad. Or should we do that now? But we should give him a chance.
- * Maybe we had a system crash or power loss before the ecc write or
- * a erase was completed.
+ * We have the raw data without ECC correction in the buffer,
+ * maybe we are lucky and all data or parts are correct. We
+ * check the node. If data are corrupted node check will sort
+ * it out. We keep this block, it will fail on write or erase
+ * and the we mark it bad. Or should we do that now? But we
+ * should give him a chance. Maybe we had a system crash or
+ * power loss before the ecc write or a erase was completed.
* So we return success. :)
*/
- ret = 0;
+ ret = 0;
}
/* if no writebuffer available or write buffer empty, return */
@@ -943,7 +945,7 @@
orbf = (c->wbuf_ofs - ofs); /* offset in read buffer */
if (orbf > len) /* is write beyond write buffer ? */
goto exit;
- lwbf = len - orbf; /* number of bytes to copy */
+ lwbf = len - orbf; /* number of bytes to copy */
if (lwbf > c->wbuf_len)
lwbf = c->wbuf_len;
}