From: Randy Dunlap <redacted>

[ Upstream commit 98701a2a861fa87a5055cf2809758e8725e8b146 ]

drivers/vdpa/mlx5/ uses vhost_iotlb*() interfaces, so select
VHOST_IOTLB to make them be built.

However, if VHOST_IOTLB is the only VHOST symbol that is
set/enabled, the object file still won't be built because
drivers/Makefile won't descend into drivers/vhost/ to build it,
so make drivers/Makefile build the needed binary whenever
VHOST_IOTLB is set, like it does for VHOST_RING.

Fixes these build errors:
ERROR: modpost: "vhost_iotlb_itree_next" [drivers/vdpa/mlx5/mlx5_vdpa.ko] undefined!
ERROR: modpost: "vhost_iotlb_itree_first" [drivers/vdpa/mlx5/mlx5_vdpa.ko] undefined!

Fixes: 29064bfdabd5 ("vdpa/mlx5: Add support library for mlx5 VDPA implementation")
Fixes: aff90770e54c ("vdpa/mlx5: Fix dependency on MLX5_CORE")
Reported-by: kernel test robot <redacted>
Signed-off-by: Randy Dunlap <redacted>
Cc: Eli Cohen <redacted>
Cc: Parav Pandit <redacted>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20201128213905.27409-1-rdunlap@infradead.org (local)
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/Makefile     | 1 +
 drivers/vdpa/Kconfig | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/Makefile b/drivers/Makefile
index c0cd1b9075e3d..5762280377186 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile

@@ -145,6 +145,7 @@ obj-$(CONFIG_OF)		+= of/
 obj-$(CONFIG_SSB)		+= ssb/
 obj-$(CONFIG_BCMA)		+= bcma/
 obj-$(CONFIG_VHOST_RING)	+= vhost/
+obj-$(CONFIG_VHOST_IOTLB)	+= vhost/
 obj-$(CONFIG_VHOST)		+= vhost/
 obj-$(CONFIG_VLYNQ)		+= vlynq/
 obj-$(CONFIG_GREYBUS)		+= greybus/

diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
index 358f6048dd3ce..6caf539091e55 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig

@@ -32,6 +32,7 @@ config IFCVF
 
 config MLX5_VDPA
 	bool
+	select VHOST_IOTLB
 	help
 	  Support library for Mellanox VDPA drivers. Provides code that is
 	  common for all types of VDPA drivers. The following drivers are planned:

-- 
2.27.0