[PATCH 4/6] pmem: Add support for direct_access()

Ross Zwisler
2015-03-16T21:13:23Z

drivers/block/pmem.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c
index 0be3669..d63bc96 100644
--- a/drivers/block/pmem.c
+++ b/drivers/block/pmem.c
@@ -74,6 +74,15 @@ static void *pmem_lookup_pg_addr(struct pmem_device *pmem, sector_t sector)
return pmem->virt_addr + offset;
}

+/* sector must be page aligned */
+static unsigned long pmem_lookup_pfn(struct pmem_device *pmem, sector_t sector)
+{
+ size_t page_offset = sector >> PAGE_SECTORS_SHIFT;
+
+ BUG_ON(sector & (PAGE_SECTORS - 1));
+ return (pmem->phys_addr >> PAGE_SHIFT) + page_offset;
+}
+
/*
* sector is not required to be page aligned.
* n is at most a single page, but could be less.
@@ -193,9 +202,24 @@ 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;
+
+ if (!pmem)
+ return -ENODEV;
+
+ *kaddr = pmem_lookup_pg_addr(pmem, sector);
+ *pfn = pmem_lookup_pfn(pmem, sector);
+
+ return pmem->size - (sector * 512);
+}
+
static const struct block_device_operations pmem_fops = {
.owner = THIS_MODULE,
.rw_page = pmem_rw_page,
+ .direct_access = pmem_direct_access,
.getgeo = pmem_getgeo,
};

--
1.9.3