2019-09-07 03:09:35

by Arnd Bergmann

Subject: [PATCH] rdma/siw: fix NOMMU build

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 <[email protected]>
---
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

2019-09-08 12:46:06

by Jason Gunthorpe

Subject: Re: [PATCH] rdma/siw: fix NOMMU build

On Fri, Sep 06, 2019 at 05:10:10PM +0200, Arnd Bergmann wrote:
> 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 <[email protected]>
> 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
> +++ 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);

I feel like !CONFIG_MMU should provide a dummy inline stub for can_do_mlock
instead?

Jason

2019-09-08 19:31:33

by Arnd Bergmann

Subject: Re: [PATCH] rdma/siw: fix NOMMU build

On Sat, Sep 7, 2019 at 9:34 AM Jason Gunthorpe <[email protected]> wrote:
> > @@ -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);
>
> I feel like !CONFIG_MMU should provide a dummy inline stub for can_do_mlock
> instead?

Fair enough. I've added that to my test tree in place of my first patch
and will send it after some more build testing.

Arnd