[PATCH v4 2/7] pmem: Enable pmem_do_write() to deal with arbitrary ranges

[Vivek Goyal <vgoyal@redhat.com>]

Currently pmem_do_write() is written with assumption that all I/O is
sector aligned. Soon I want to use this function in zero_page_range()
where range passed in does not have to be sector aligned.

Modify this function to be able to deal with an arbitrary range. Which
is specified by pmem_off and len.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 drivers/nvdimm/pmem.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 075b11682192..fae8f67da9de 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -154,15 +154,23 @@ static blk_status_t pmem_do_read(struct pmem_device *pmem,
 
 static blk_status_t pmem_do_write(struct pmem_device *pmem,
 			struct page *page, unsigned int page_off,
-			sector_t sector, unsigned int len)
+			u64 pmem_off, unsigned int len)
 {
 	blk_status_t rc = BLK_STS_OK;
 	bool bad_pmem = false;
-	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)))
-		bad_pmem = true;
+	phys_addr_t pmem_real_off = pmem_off + pmem->data_offset;
+	void *pmem_addr = pmem->virt_addr + pmem_real_off;
+	sector_t sector_start, sector_end;
+	unsigned nr_sectors;
+
+	sector_start = DIV_ROUND_UP(pmem_off, SECTOR_SIZE);
+	sector_end = (pmem_off + len) >> SECTOR_SHIFT;
+	if (sector_end > sector_start) {
+		nr_sectors = sector_end - sector_start;
+		if (is_bad_pmem(&pmem->bb, sector_start,
+				nr_sectors << SECTOR_SHIFT))
+			bad_pmem = true;
+	}
 
 	/*
 	 * Note that we write the data both before and after
@@ -181,7 +189,13 @@ static blk_status_t pmem_do_write(struct pmem_device *pmem,
 	flush_dcache_page(page);
 	write_pmem(pmem_addr, page, page_off, len);
 	if (unlikely(bad_pmem)) {
-		rc = pmem_clear_poison(pmem, pmem_off, len);
+		/*
+		 * Pass sector aligned offset and length. That seems
+		 * to work as of now. Other finer grained alignment
+		 * cases can be addressed later if need be.
+		 */
+		rc = pmem_clear_poison(pmem, ALIGN(pmem_real_off, SECTOR_SIZE),
+				       nr_sectors << SECTOR_SHIFT);
 		write_pmem(pmem_addr, page, page_off, len);
 	}
 
@@ -206,7 +220,7 @@ static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
 	bio_for_each_segment(bvec, bio, iter) {
 		if (op_is_write(bio_op(bio)))
 			rc = pmem_do_write(pmem, bvec.bv_page, bvec.bv_offset,
-				iter.bi_sector, bvec.bv_len);
+				iter.bi_sector << SECTOR_SHIFT, bvec.bv_len);
 		else
 			rc = pmem_do_read(pmem, bvec.bv_page, bvec.bv_offset,
 				iter.bi_sector, bvec.bv_len);
@@ -235,7 +249,7 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 	blk_status_t rc;
 
 	if (op_is_write(op))
-		rc = pmem_do_write(pmem, page, 0, sector,
+		rc = pmem_do_write(pmem, page, 0, sector << SECTOR_SHIFT,
 				   hpage_nr_pages(page) * PAGE_SIZE);
 	else
 		rc = pmem_do_read(pmem, page, 0, sector,
-- 
2.20.1