[v3,1/7] pmem: Add functions for reading/writing page to/from pmem
diff mbox series

Message ID 20200207202652.1439-2-vgoyal@redhat.com
State New
Headers show
Series
  • dax,pmem: Provide a dax operation to zero range of memory
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Commit Message

Vivek Goyal Feb. 7, 2020, 8:26 p.m. UTC
This splits pmem_do_bvec() into pmem_do_read() and pmem_do_write().
pmem_do_write() will be used by pmem zero_page_range() as well. Hence
sharing the same code.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 drivers/nvdimm/pmem.c | 79 ++++++++++++++++++++++++++-----------------
 1 file changed, 48 insertions(+), 31 deletions(-)

Comments

Christoph Hellwig Feb. 17, 2020, 1:21 p.m. UTC | #1
On Fri, Feb 07, 2020 at 03:26:46PM -0500, Vivek Goyal wrote:
> +static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
> +			unsigned int len, unsigned int off, unsigned int op,
> +			sector_t sector)
> +{
> +	if (!op_is_write(op))
> +		return pmem_do_read(pmem, page, off, sector, len);
> +
> +	return pmem_do_write(pmem, page, off, sector, len);

Why not:

	if (op_is_write(op))
		return pmem_do_write(pmem, page, off, sector, len);
	return pmem_do_read(pmem, page, off, sector, len);

that being said I don't see the point of this pmem_do_bvec helper given
that it only has two callers.

The rest looks good to me.
Vivek Goyal Feb. 17, 2020, 6:04 p.m. UTC | #2
On Mon, Feb 17, 2020 at 05:21:38AM -0800, Christoph Hellwig wrote:
> On Fri, Feb 07, 2020 at 03:26:46PM -0500, Vivek Goyal wrote:
> > +static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
> > +			unsigned int len, unsigned int off, unsigned int op,
> > +			sector_t sector)
> > +{
> > +	if (!op_is_write(op))
> > +		return pmem_do_read(pmem, page, off, sector, len);
> > +
> > +	return pmem_do_write(pmem, page, off, sector, len);
> 
> Why not:
> 
> 	if (op_is_write(op))
> 		return pmem_do_write(pmem, page, off, sector, len);
> 	return pmem_do_read(pmem, page, off, sector, len);
> 
> that being said I don't see the point of this pmem_do_bvec helper given
> that it only has two callers.

Ok, I am about to post V4 of patches and I got rid of pmem_do_bvec() and
callers are directly calling pmem_do_read()/pmem_do_write().

Vivek

Patch
diff mbox series

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index ad8e4df1282b..9ad07cb8c9fc 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -136,9 +136,25 @@  static blk_status_t read_pmem(struct page *page, unsigned int off,
 	return BLK_STS_OK;
 }
 
-static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
-			unsigned int len, unsigned int off, unsigned int op,
-			sector_t sector)
+static blk_status_t pmem_do_read(struct pmem_device *pmem,
+			struct page *page, unsigned int page_off,
+			sector_t sector, unsigned int len)
+{
+	blk_status_t rc;
+	phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
+	void *pmem_addr = pmem->virt_addr + pmem_off;
+
+	if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
+		return BLK_STS_IOERR;
+
+	rc = read_pmem(page, page_off, pmem_addr, len);
+	flush_dcache_page(page);
+	return rc;
+}
+
+static blk_status_t pmem_do_write(struct pmem_device *pmem,
+			struct page *page, unsigned int page_off,
+			sector_t sector, unsigned int len)
 {
 	blk_status_t rc = BLK_STS_OK;
 	bool bad_pmem = false;
@@ -148,39 +164,40 @@  static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 	if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
 		bad_pmem = true;
 
-	if (!op_is_write(op)) {
-		if (unlikely(bad_pmem))
-			rc = BLK_STS_IOERR;
-		else {
-			rc = read_pmem(page, off, pmem_addr, len);
-			flush_dcache_page(page);
-		}
-	} else {
-		/*
-		 * Note that we write the data both before and after
-		 * clearing poison.  The write before clear poison
-		 * handles situations where the latest written data is
-		 * preserved and the clear poison operation simply marks
-		 * the address range as valid without changing the data.
-		 * In this case application software can assume that an
-		 * interrupted write will either return the new good
-		 * data or an error.
-		 *
-		 * However, if pmem_clear_poison() leaves the data in an
-		 * indeterminate state we need to perform the write
-		 * after clear poison.
-		 */
-		flush_dcache_page(page);
-		write_pmem(pmem_addr, page, off, len);
-		if (unlikely(bad_pmem)) {
-			rc = pmem_clear_poison(pmem, pmem_off, len);
-			write_pmem(pmem_addr, page, off, len);
-		}
+	/*
+	 * Note that we write the data both before and after
+	 * clearing poison.  The write before clear poison
+	 * handles situations where the latest written data is
+	 * preserved and the clear poison operation simply marks
+	 * the address range as valid without changing the data.
+	 * In this case application software can assume that an
+	 * interrupted write will either return the new good
+	 * data or an error.
+	 *
+	 * However, if pmem_clear_poison() leaves the data in an
+	 * indeterminate state we need to perform the write
+	 * after clear poison.
+	 */
+	flush_dcache_page(page);
+	write_pmem(pmem_addr, page, page_off, len);
+	if (unlikely(bad_pmem)) {
+		rc = pmem_clear_poison(pmem, pmem_off, len);
+		write_pmem(pmem_addr, page, page_off, len);
 	}
 
 	return rc;
 }
 
+static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
+			unsigned int len, unsigned int off, unsigned int op,
+			sector_t sector)
+{
+	if (!op_is_write(op))
+		return pmem_do_read(pmem, page, off, sector, len);
+
+	return pmem_do_write(pmem, page, off, sector, len);
+}
+
 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
 {
 	int ret = 0;