[PATCH v3] libnvdimm: check and clear poison before writing to pmem

[PATCH v3] libnvdimm: check and clear poison before writing to pmem

[Dave Jiang]

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 |   30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index d5dc80c..494536c 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -226,6 +226,12 @@ 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 -EINVAL;
 
 	if (unlikely(offset + size > nsio->size)) {
 		dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
@@ -233,17 +239,33 @@ 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)))
+		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)

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Re: [PATCH v3] libnvdimm: check and clear poison before writing to pmem

[Vishal Verma]

On 11/11, Dave Jiang wrote:
> 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 |   30 ++++++++++++++++++++++++++----
>  1 file changed, 26 insertions(+), 4 deletions(-)

Looks good!

Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>

> 
> diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
> index d5dc80c..494536c 100644
> --- a/drivers/nvdimm/claim.c
> +++ b/drivers/nvdimm/claim.c
> @@ -226,6 +226,12 @@ 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 -EINVAL;
>  
>  	if (unlikely(offset + size > nsio->size)) {
>  		dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
> @@ -233,17 +239,33 @@ 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)))
> +		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)
> 
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