Re: [PATCH RFC V2 0/6] rxe_map_mr_sg() fix cleanup and refactor

[Zhu Yanjun]

在 2023/11/6 12:07, Zhijian Li (Fujitsu) 写道:
> On 03/11/2023 21:00, Zhu Yanjun wrote:
> > 在 2023/11/3 17:55, Li Zhijian 写道:
> > > I don't collect the Reviewed-by to the patch1-2 this time, since i
> > > think we can make it better.
> > >
> > > Patch1-2: Fix kernel panic[1] and benifit to make srp work again.
> > >             Almost nothing change from V1.
> > > Patch3-5: cleanups # newly add
> > > Patch6: make RXE support PAGE_SIZE aligned mr # newly add, but not fully tested
> > >
> > > My bad arm64 mechine offten hangs when doing blktests even though i use the
> > > default siw driver.
> > >
> > > - nvme and ULPs(rtrs, iser) always registers 4K mr still don't supported yet.
> >
> > Zhijian
> >
> > Please read carefully the whole discussion about this problem. You will find a lot of valuable suggestions, especially suggestions from Jason.
>
> Okay, i will read it again. If you can tell me which thread, that would be better.
>
>
> >   From the whole discussion, it seems that the root cause is very clear.
> > We need to fix this prolem. Please do not send this kind of commits again.
>
> Let's think about what's our goal first.
>
> - 1) Fix the panic[1] and only support PAGE_SIZE MR
> - 2) support PAGE_SIZE aligned MR
> - 3) support any page_size MR.
>
> I'm sorry i'm not familiar with the linux MM subsystem. It seem it's safe/correct to access
> address/memory across pages start from the return of kmap_loca_page(page).
> In other words, 2) is already native supported, right?

Yes. Please read the comments from Jason, Leon and Bart. They shared a 
lot of good advice. From them, we can know the root cause and how to fix 
this problem.

Good Luck.

Zhu Yanjun

> I get totally confused now.
>
>
>
> > Zhu Yanjun
> >
> > > [1] https://lore.kernel.org/all/CAHj4cs9XRqE25jyVw9rj9YugffLn5+f=1znaBEnu1usLOciD+g@xxxxxxxxxxxxxx/T/
> > >
> > > Li Zhijian (6):
> > >     RDMA/rxe: RDMA/rxe: don't allow registering !PAGE_SIZE mr
> > >     RDMA/rxe: set RXE_PAGE_SIZE_CAP to PAGE_SIZE
> > >     RDMA/rxe: remove unused rxe_mr.page_shift
> > >     RDMA/rxe: Use PAGE_SIZE and PAGE_SHIFT to extract address from
> > >       page_list
> > >     RDMA/rxe: cleanup rxe_mr.{page_size,page_shift}
> > >     RDMA/rxe: Support PAGE_SIZE aligned MR
> > >
> > >    drivers/infiniband/sw/rxe/rxe_mr.c    | 80 ++++++++++++++++-----------
> > >    drivers/infiniband/sw/rxe/rxe_param.h |  2 +-
> > >    drivers/infiniband/sw/rxe/rxe_verbs.h |  9 ---
> > >    3 files changed, 48 insertions(+), 43 deletions(-)