On Tue, Aug 16, 2022 at 5:03 PM Jason Gunthorpe <jgg@xxxxxxxxxx> wrote:
>
> ib_umem_dmabuf_map_pages() returns 0 on success and -ERRNO on failure.
>
> dma_resv_wait_timeout() uses a different scheme:
>
> * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
> * greater than zero on success.
>
> This results in ib_umem_dmabuf_map_pages() being non-functional as a
> positive return will be understood to be an error by drivers.
>
> Fixes: f30bceab16d1 ("RDMA: use dma_resv_wait() instead of extracting the fence")
> Cc: stable@xxxxxxxxxx
> Tested-by: Maor Gottlieb <maorg@xxxxxxxxxx>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> ---
> drivers/infiniband/core/umem_dmabuf.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> Oded, I assume the Habana driver will hit this as well - does this mean you
> are not testing upstream kernels?
Thanks Jason for letting me know.
You are correct, we don't use upstream kernels.
We use a back-ported EFA driver for 5.15 which in that version,
ib_umem_dmabuf_map_pages() calls dma_resv_excl_fence().
So I guess that's why we didn't encounter this issue.
Thanks,
oded
>
> diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
> index fce80a4a5147cd..04c04e6d24c358 100644
> --- a/drivers/infiniband/core/umem_dmabuf.c
> +++ b/drivers/infiniband/core/umem_dmabuf.c
> @@ -18,6 +18,7 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
> struct scatterlist *sg;
> unsigned long start, end, cur = 0;
> unsigned int nmap = 0;
> + long ret;
> int i;
>
> dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
> @@ -67,9 +68,14 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
> * may be not up-to-date. Wait for the exporter to finish
> * the migration.
> */
> - return dma_resv_wait_timeout(umem_dmabuf->attach->dmabuf->resv,
> + ret = dma_resv_wait_timeout(umem_dmabuf->attach->dmabuf->resv,
> DMA_RESV_USAGE_KERNEL,
> false, MAX_SCHEDULE_TIMEOUT);
> + if (ret < 0)
> + return ret;
> + if (ret == 0)
> + return -ETIMEDOUT;
> + return 0;
> }
> EXPORT_SYMBOL(ib_umem_dmabuf_map_pages);
>
>
> base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
> --
> 2.37.2
>
