[PATCH 5.5 296/367] IB/core: Fix ODP with IB_ACCESS_HUGETLB handling

Greg Kroah-Hartman
2020-02-10T12:54:17Z

From: Yishai Hadas <yishaih@mellanox.com>

commit 9ff1b6466a291a33389c4a9c7f3f9b64d62df40a upstream.

As VMAs for a given range might not be available as part of the
registration phase in ODP.

ib_init_umem_odp() considered the expected page shift value that was
previously set and initializes its internals accordingly.

If memory isn't backed by physical contiguous pages aligned to a hugepage
boundary an error will be set as part of the page fault flow and come back
to the user as some failed RDMA operation.

Fixes: 0008b84ea9af ("IB/umem: Add support to huge ODP")
Link: https://lore.kernel.org/r/20191222124649.52300-4-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/core/umem_odp.c | 21 ++++-----------------
1 file changed, 4 insertions(+), 17 deletions(-)

--- 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(stru
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);
@@ -266,7 +254,6 @@ struct ib_umem_odp *ib_umem_odp_get(stru

err_put_pid:
put_pid(umem_odp->tgid);
-err_free:
kfree(umem_odp);
return ERR_PTR(ret);
}