linux-kernel - [PATCH 4/6] pmem, nd_blk: update I/O paths to use PMEM API

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Date:	Thu, 28 May 2015 16:35:51 -0600
From:	Ross Zwisler <ross.zwisler@...ux.intel.com>
To:	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	linux-nvdimm@...ts.01.org
Cc:	Ross Zwisler <ross.zwisler@...ux.intel.com>,
	Dan Williams <dan.j.williams@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: [PATCH 4/6] pmem, nd_blk: update I/O paths to use PMEM API

Update the PMEM and ND_BLK I/O paths to use the new PMEM API and to
adhere to the read/write flows outlined in the "NVDIMM Block Window
Driver Writer's Guide":

http://pmem.io/documents/NVDIMM_Driver_Writers_Guide.pdf

Signed-off-by: Ross Zwisler <ross.zwisler@...ux.intel.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: linux-nvdimm@...ts.01.org
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: linux-acpi@...r.kernel.org
---
 drivers/acpi/nfit.c     | 10 ++++++++--
 drivers/block/nd/pmem.c | 15 +++++++++++----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index df14652ea13e..22df61968c1c 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -18,6 +18,7 @@
 #include <linux/list.h>
 #include <linux/acpi.h>
 #include <linux/sort.h>
+#include <linux/pmem.h>
 #include <linux/io.h>
 #include "nfit.h"
 
@@ -926,7 +927,9 @@ static void write_blk_ctl(struct nfit_blk *nfit_blk, unsigned int bw,
 	if (mmio->num_lines)
 		offset = to_interleave_offset(offset, mmio);
 
+	/* mmio->base must be mapped uncacheable */
 	writeq(cmd, mmio->base + offset);
+	persistent_sync();
 	/* FIXME: conditionally perform read-back if mandated by firmware */
 }
 
@@ -940,7 +943,6 @@ static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk, void *iobuf,
 	int rc;
 
 	base_offset = nfit_blk->bdw_offset + dpa % L1_CACHE_BYTES + bw * mmio->size;
-	/* TODO: non-temporal access, flush hints, cache management etc... */
 	write_blk_ctl(nfit_blk, bw, dpa, len, write);
 	while (len) {
 		unsigned int c;
@@ -959,13 +961,17 @@ static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk, void *iobuf,
 		}
 
 		if (write)
-			memcpy(mmio->aperture + offset, iobuf + copied, c);
+			persistent_copy(mmio->aperture + offset, iobuf + copied, c);
 		else
 			memcpy(iobuf + copied, mmio->aperture + offset, c);
 
 		copied += c;
 		len -= c;
 	}
+
+	if (write)
+		persistent_sync();
+
 	rc = read_blk_stat(nfit_blk, bw) ? -EIO : 0;
 	return rc;
 }
diff --git a/drivers/block/nd/pmem.c b/drivers/block/nd/pmem.c
index a8712e41e7f5..1a447c351aef 100644
--- a/drivers/block/nd/pmem.c
+++ b/drivers/block/nd/pmem.c
@@ -15,15 +15,16 @@
  * more details.
  */
 
-#include <asm/cacheflush.h>
 #include <linux/blkdev.h>
 #include <linux/hdreg.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/pmem.h>
 #include <linux/slab.h>
 #include <linux/nd.h>
+#include <asm/cacheflush.h>
 #include "nd.h"
 
 struct pmem_device {
@@ -51,7 +52,7 @@ static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 		flush_dcache_page(page);
 	} else {
 		flush_dcache_page(page);
-		memcpy(pmem->virt_addr + pmem_off, mem + off, len);
+		persistent_copy(pmem->virt_addr + pmem_off, mem + off, len);
 	}
 
 	kunmap_atomic(mem);
@@ -82,6 +83,8 @@ static void pmem_make_request(struct request_queue *q, struct bio *bio)
 		sector += bvec.bv_len >> 9;
 	}
 
+	if (rw & WRITE)
+		persistent_sync();
 out:
 	bio_endio(bio, err);
 }
@@ -92,6 +95,8 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 	struct pmem_device *pmem = bdev->bd_disk->private_data;
 
 	pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
+	if (rw & WRITE)
+		persistent_sync();
 	page_endio(page, rw & WRITE, 0);
 
 	return 0;
@@ -111,8 +116,10 @@ static int pmem_rw_bytes(struct nd_io *ndio, void *buf, size_t offset,
 
 	if (rw == READ)
 		memcpy(buf, pmem->virt_addr + offset, n);
-	else
-		memcpy(pmem->virt_addr + offset, buf, n);
+	else {
+		persistent_copy(pmem->virt_addr + offset, buf, n);
+		persistent_sync();
+	}
 
 	return 0;
 }
-- 
1.9.3

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