dm stripe: add DAX support

Change dm-stripe to implement direct_access function,
stripe_direct_access(), which maps bdev and 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>

1 files changed, 25 insertions, 1 deletions

diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index 48f1c01d7b9f..01bb9cf2a8c2 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -308,6 +308,29 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
         return DM_MAPIO_REMAPPED;
 }
 
+static long stripe_direct_access(struct dm_target *ti, sector_t sector,
+                                 void __pmem **kaddr, pfn_t *pfn, long size)
+{
+        struct stripe_c *sc = ti->private;
+        uint32_t stripe;
+        struct block_device *bdev;
+        struct blk_dax_ctl dax = {
+                .size = size,
+        };
+        long ret;
+
+        stripe_map_sector(sc, sector, &stripe, &dax.sector);
+
+        dax.sector += sc->stripe[stripe].physical_start;
+        bdev = sc->stripe[stripe].dev->bdev;
+
+        ret = bdev_direct_access(bdev, &dax);
+        *kaddr = dax.addr;
+        *pfn = dax.pfn;
+
+        return ret;
+}
+
 /*
  * Stripe status:
  *
@@ -416,7 +439,7 @@ static void stripe_io_hints(struct dm_target *ti,
 
 static struct target_type stripe_target = {
         .name   = "striped",
-        .version = {1, 5, 1},
+        .version = {1, 6, 0},
         .module = THIS_MODULE,
         .ctr    = stripe_ctr,
         .dtr    = stripe_dtr,
@@ -425,6 +448,7 @@ static struct target_type stripe_target = {
         .status = stripe_status,
         .iterate_devices = stripe_iterate_devices,
         .io_hints = stripe_io_hints,
+        .direct_access = stripe_direct_access,
 };
 
 int __init dm_stripe_init(void)