libnvdimm: check and clear poison before writing to pmem

davejiang · djbw · commit 82bf1037f2ca · 2016-11-11T20:35:31.000-08:00
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 &lt;dave.jiang@intel.com&gt;
Reviewed-by: Vishal Verma &lt;vishal.l.verma@intel.com&gt;
[djbw: fixup 0-length write request to succeed]
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
@@ -226,24 +226,46 @@ 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);
+	sector_t sector = offset >> 9;
+	int rc = 0;
+
+	if (unlikely(!size))
+		return 0;
 
 	if (unlikely(offset + size > nsio->size)) {
 		dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 		return -EFAULT;
 	}
 
 	if (rw == READ) {
-		unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
-
-		if (unlikely(is_bad_pmem(&nsio->bb, offset / 512, sz_align)))
+		if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align)))
 			return -EIO;
 		return memcpy_from_pmem(buf, nsio->addr + offset, size);
 	} else {
+
+		if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) {
+			if (IS_ALIGNED(offset, 512) && IS_ALIGNED(size, 512)) {
+				long cleared;
+
+				cleared = nvdimm_clear_poison(&ndns->dev,
+							      offset, size);
+				if (cleared != size) {
+					size = cleared;
+					rc = -EIO;
+				}
+
+				badblocks_clear(&nsio->bb, sector,
+						cleared >> 9);
+			} else
+				rc = -EIO;
+		}
+
 		memcpy_to_pmem(nsio->addr + offset, buf, size);
 		nvdimm_flush(to_nd_region(ndns->dev.parent));
 	}
 
-	return 0;
+	return rc;
 }
 
 int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio)
