[PATCH RFC 10/19] RDMA/umem: remove FOLL_FORCE usage

Leon Romanovsky leon at kernel.org
Mon Nov 14 08:30:11 UTC 2022


On Mon, Nov 07, 2022 at 05:17:31PM +0100, David Hildenbrand wrote:
> GUP now supports reliable R/O long-term pinning in COW mappings, such
> that we break COW early. MAP_SHARED VMAs only use the shared zeropage so
> far in one corner case (DAXFS file with holes), which can be ignored
> because GUP does not support long-term pinning in fsdax (see
> check_vma_flags()).
> 
> Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required
> for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop
> using FOLL_FORCE, which is really only for debugger access.
> 
> Cc: Jason Gunthorpe <jgg at ziepe.ca>
> Cc: Leon Romanovsky <leon at kernel.org>
> Signed-off-by: David Hildenbrand <david at redhat.com>
> ---
>  drivers/infiniband/core/umem.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Thanks,
Tested-by: Leon Romanovsky <leonro at nvidia.com> # Over mlx4 and mlx5.


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