On Mon, Jun 17, 2024 at 10:59:05AM -0300, Jason Gunthorpe wrote: > On Thu, Jun 13, 2024 at 09:01:42PM +0300, Leon Romanovsky wrote: > > From: Chiara Meiohas <cmeiohas@xxxxxxxxxx> > > > > Set the mkey for dmabuf at PAGE_SIZE to support any SGL > > after a move operation. > > > > ib_umem_find_best_pgsz returns 0 on error, so it is > > incorrect to check the returned page_size against PAGE_SIZE > > This commit message is not clear enough for something that need to be > backported: This patch is going to be backported without any relation to the commit message as it has Fixes line. Thanks > > RDMA/mlx5: Support non-page size aligned DMABUF mkeys > > The mkey page size for DMABUF is fixed at PAGE_SIZE because we have to > support a move operation that could change a large-sized page list > into a small page-list and the mkey must be able to represent it. > > The test for this is not quite correct, instead of checking the output > of mlx5_umem_find_best_pgsz() the call to ib_umem_find_best_pgsz > should specify the exact HW/SW restriction - only PAGE_SIZE is > accepted. > > Then the normal logic for dealing with leading/trailing sub page > alignment works correctly and sub page size DMBUF mappings can be > supported. > > This is particularly painful on 64K kernels. Unfortunately, the patch was already merged, so I can't change the commit message in for-next branch. Thanks > > Jason
