dax, dm: allow device-mapper to operate without dax support
Change device-mapper's DAX dependency to require the presence of at
least one DAX_DRIVER. This allows device-mapper to be built without
bringing the DAX core along which is especially wasteful when there are
no DAX drivers, like BLK_DEV_PMEM, configured.
Cc: Alasdair Kergon <agk@redhat.com>
Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index b5e8921..ac2e8ee 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -311,6 +311,7 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_REMAPPED;
}
+#if IS_ENABLED(CONFIG_DAX_DRIVER)
static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
@@ -351,6 +352,11 @@ static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}
+#else
+#define stripe_dax_direct_access NULL
+#define stripe_dax_copy_from_iter NULL
+#endif
+
/*
* Stripe status:
*