Re: [PATCH rdma-rc 3/3] IB/core: Fix ODP with IB_ACCESS_HUGETLB handling

From: Geert Uytterhoeven
Date: Wed Jan 08 2020 - 07:57:06 EST


Hi Leon,

On Thu, 19 Dec 2019, Leon Romanovsky wrote:
From: Yishai Hadas <yishaih@xxxxxxxxxxxx>

As VMAs for a given range might not be available as part of the
registration phase in ODP, IB_ACCESS_HUGETLB/page_shift must be checked
as part of the page fault flow.

If the application didn't mmap the backed memory with huge pages or
released part of that hugepage area, an error will be set as part of the
page fault flow once be detected.

Fixes: 0008b84ea9af ("IB/umem: Add support to huge ODP")
Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxxxx>
Reviewed-by: Artemy Kovalyov <artemyko@xxxxxxxxxxxx>
Reviewed-by: Aviad Yehezkel <aviadye@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>

Thanks for your patch!

--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -241,22 +241,10 @@ struct ib_umem_odp *ib_umem_odp_get(struct ib_udata *udata, unsigned long addr,
umem_odp->umem.owning_mm = mm = current->mm;
umem_odp->notifier.ops = ops;

- umem_odp->page_shift = PAGE_SHIFT;
- if (access & IB_ACCESS_HUGETLB) {
- struct vm_area_struct *vma;
- struct hstate *h;
-
- down_read(&mm->mmap_sem);
- vma = find_vma(mm, ib_umem_start(umem_odp));
- if (!vma || !is_vm_hugetlb_page(vma)) {
- up_read(&mm->mmap_sem);
- ret = -EINVAL;
- goto err_free;
- }
- h = hstate_vma(vma);
- umem_odp->page_shift = huge_page_shift(h);
- up_read(&mm->mmap_sem);
- }
+ if (access & IB_ACCESS_HUGETLB)
+ umem_odp->page_shift = HPAGE_SHIFT;
+ else
+ umem_odp->page_shift = PAGE_SHIFT;

umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
ret = ib_init_umem_odp(umem_odp, ops);

noreply@xxxxxxxxxxxxxx reports for linux-next/m68k-allmodconfig/m68k:

drivers/infiniband/core/umem_odp.c:245:26: error: 'HPAGE_SHIFT' undeclared (first use in this function); did you mean 'PAGE_SHIFT'?

Should this depend on some HUGETLBFS option?

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds