On Tue, Oct 27, 2020 at 08:33:52PM +0000, Xiong, Jianxin wrote: > > > @@ -801,6 +816,52 @@ static int pagefault_implicit_mr(struct mlx5_ib_mr *imr, > > > * Returns: > > > * -EFAULT: The io_virt->bcnt is not within the MR, it covers pages that are > > > * not accessible, or the MR is no longer valid. > > > + * -EAGAIN: The operation should be retried > > > + * > > > + * >0: Number of pages mapped > > > + */ > > > +static int pagefault_dmabuf_mr(struct mlx5_ib_mr *mr, struct ib_umem *umem, > > > + u64 io_virt, size_t bcnt, u32 *bytes_mapped, > > > + u32 flags) > > > +{ > > > + struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem); > > > + u64 user_va; > > > + u64 end; > > > + int npages; > > > + int err; > > > + > > > + if (unlikely(io_virt < mr->mmkey.iova)) > > > + return -EFAULT; > > > + if (check_add_overflow(io_virt - mr->mmkey.iova, > > > + (u64)umem->address, &user_va)) > > > + return -EFAULT; > > > + /* Overflow has alreddy been checked at the umem creation time */ > > > + end = umem->address + umem->length; > > > + if (unlikely(user_va >= end || end - user_va < bcnt)) > > > + return -EFAULT; > > > > Why duplicate this sequence? Caller does it > > The sequence in the caller is for umem_odp only. Nothing about umem_odp in this code though?? > > > /* prefetch with write-access must be supported by the MR */ > > > if (advice == IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_WRITE && > > > - !odp->umem.writable) > > > + !mr->umem->writable) > > > > ?? > There is no need to use umem_odp here, mr->umem is the same as &odp->umem. > This change makes the code works for both umem_odp and umem_dmabuf. Ok Can you please also think about how to test this? I very much prefer to see new pyverbs tests for new APIs. Distros are running the rdma-core test suite, if you want this to work widely we need a public test for it. Thanks, Jason