[PATCH] rdma/siw: fix NOMMU build

[Arnd Bergmann]

On kernels without CONFIG_MMU, we get a link error for the siw
driver:

drivers/infiniband/sw/siw/siw_mem.o: In function `siw_umem_get':
siw_mem.c:(.text+0x4c8): undefined reference to `can_do_mlock'

I don't know whether this driver is able to work at all without
an MMU, but it's easy to avoid the link problem by adding another
compile-time check.

Fixes: 2251334dcac9 ("rdma/siw: application buffer management")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 drivers/infiniband/sw/siw/siw_mem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/siw/siw_mem.c b/drivers/infiniband/sw/siw/siw_mem.c
index e99983f07663..b3b614c07fdb 100644
--- a/drivers/infiniband/sw/siw/siw_mem.c
+++ b/drivers/infiniband/sw/siw/siw_mem.c
@@ -374,7 +374,7 @@ struct siw_umem *siw_umem_get(u64 start, u64 len, bool writable)
 	unsigned int foll_flags = FOLL_WRITE;
 	int num_pages, num_chunks, i, rv = 0;
 
-	if (!can_do_mlock())
+	if (!IS_ENABLED(CONFIG_MMU) || !can_do_mlock())
 		return ERR_PTR(-EPERM);
 
 	if (!len)
-- 
2.20.0