On Wed, Nov 16, 2022 at 11:26:50AM +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 ptrace access.
Cc: Christian Benvenuti benve@cisco.com Cc: Nelson Escobar neescoba@cisco.com Cc: Jason Gunthorpe jgg@ziepe.ca Cc: Leon Romanovsky leon@kernel.org Signed-off-by: David Hildenbrand david@redhat.com
drivers/infiniband/hw/usnic/usnic_uiom.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
Reviewed-by: Jason Gunthorpe jgg@nvidia.com
Jason