dm linear: add DAX support

Change dm-linear to implement direct_access function,
linear_direct_access(), which maps sector and calls direct_access
function of its physical target device.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 05c35aa..6d35dd4 100644 (file)
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -141,9 +141,27 @@ static int linear_iterate_devices(struct dm_target *ti,
        return fn(ti, lc->dev, lc->start, ti->len, data);
 }
 
+static long linear_direct_access(struct dm_target *ti, sector_t sector,
+                                void __pmem **kaddr, pfn_t *pfn, long size)
+{
+       struct linear_c *lc = ti->private;
+       struct block_device *bdev = lc->dev->bdev;
+       struct blk_dax_ctl dax = {
+               .sector = linear_map_sector(ti, sector),
+               .size = size,
+       };
+       long ret;
+
+       ret = bdev_direct_access(bdev, &dax);
+       *kaddr = dax.addr;
+       *pfn = dax.pfn;
+
+       return ret;
+}
+
 static struct target_type linear_target = {
        .name   = "linear",
-       .version = {1, 2, 1},
+       .version = {1, 3, 0},
        .module = THIS_MODULE,
        .ctr    = linear_ctr,
        .dtr    = linear_dtr,
@@ -151,6 +169,7 @@ static struct target_type linear_target = {
        .status = linear_status,
        .prepare_ioctl = linear_prepare_ioctl,
        .iterate_devices = linear_iterate_devices,
+       .direct_access = linear_direct_access,
 };
 
 int __init dm_linear_init(void)