[PATCH] libnvdimm: check and clear poison before writing to pmem

From: Dave Jiang <dave.jiang@intel.com>
To: vishal.l.verma@intel.com, dan.j.williams@intel.com,
	ross.zwisler@linux.intel.com
Cc: linux-nvdimm@lists.01.org
Subject: [PATCH] libnvdimm: check and clear poison before writing to pmem
Date: Wed, 09 Nov 2016 16:20:42 -0700	[thread overview]
Message-ID: <147873364251.45471.9613527969861188296.stgit@djiang5-desk3.ch.intel.com> (raw)

We need to clear any poison when we are writing to pmem. The granularity
will be sector size. If it's less then we can't do anything about it
barring corruption.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/nvdimm/claim.c |   20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index d5dc80c..2078d25 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -226,6 +226,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
 		resource_size_t offset, void *buf, size_t size, int rw)
 {
 	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
+	unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
 
 	if (unlikely(offset + size > nsio->size)) {
 		dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
@@ -233,12 +234,27 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
 	}
 
 	if (rw == READ) {
-		unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
-
 		if (unlikely(is_bad_pmem(&nsio->bb, offset / 512, sz_align)))
 			return -EIO;
 		return memcpy_from_pmem(buf, nsio->addr + offset, size);
 	} else {
+		sector_t sector = offset / 512;
+
+		if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) {
+			if (IS_ALIGNED(offset, 512) &&
+			    IS_ALIGNED(size, 512) && (size >= 512)) {
+				int rc;
+
+				rc = nvdimm_clear_poison(&ndns->dev, offset,
+							 size);
+				if (rc != size)
+					return -EIO;
+
+				badblocks_clear(&nsio->bb, sector, rc / 512);
+			} else
+				return -EIO;
+		}
+
 		memcpy_to_pmem(nsio->addr + offset, buf, size);
 		nvdimm_flush(to_nd_region(ndns->dev.parent));
 	}

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm
