[PATCH 4/8] pmem: Add support for direct_access()

[Boaz Harrosh]

From: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>

Also fixed a top the initial version
[boaz]
  SQUASHME pmem: Micro optimization the hotpath 002

Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Boaz Harrosh <boaz@xxxxxxxxxxxxx>
---
 drivers/block/pmem.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c
index 750ffdf..f0f0ba0 100644
--- a/drivers/block/pmem.c
+++ b/drivers/block/pmem.c
@@ -111,9 +111,25 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 	return 0;
 }
 
+static long pmem_direct_access(struct block_device *bdev, sector_t sector,
+			      void **kaddr, unsigned long *pfn, long size)
+{
+	struct pmem_device *pmem = bdev->bd_disk->private_data;
+	size_t offset = sector << 9;
+
+	if (unlikely(!pmem))
+		return -ENODEV;
+
+	*kaddr = pmem->virt_addr + offset;
+	*pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
+
+	return pmem->size - offset;
+}
+
 static const struct block_device_operations pmem_fops = {
 	.owner =		THIS_MODULE,
 	.rw_page =		pmem_rw_page,
+	.direct_access =	pmem_direct_access,
 };
 
 /* Kernel module stuff */
-- 
1.9.3

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