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

[Zhijian Li (Fujitsu)]

Very thanks for all your feedback.

On 03/11/2023 17:55, Li Zhijian wrote:
> 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.

Quote from Jason:
"
> The concept was that the xarray could store anything larger than
> PAGE_SIZE and the entry would point at the first struct page of the
> contiguous chunk
> 
> That looks like it is right, or at least close to right, so lets try
> to keep it
"


It seems it's okay to access address/memory across pages on RXE even though
we only map the first page.

That also means PAGE_SIZE aligned MR is already supported, so only check
`if (IS_ALIGNED(page_size, PAGE_SIZE))` is sufficient, right?

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index f54042e9aeb2..3755e530e6dc 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -234,6 +234,12 @@ int rxe_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sgl,
         struct rxe_mr *mr = to_rmr(ibmr);
         unsigned int page_size = mr_page_size(mr);
  
+       if (!IS_ALIGNED(page_size, PAGE_SIZE)) {
+               rxe_err_mr(mr, "FIXME...\n")
+               return -EINVAL;
+       }
+
         mr->nbuf = 0;
         mr->page_shift = ilog2(page_size);
         mr->page_mask = ~((u64)page_size - 1);
diff --git a/drivers/infiniband/sw/rxe/rxe_param.h b/drivers/infiniband/sw/rxe/rxe_param.h
index d2f57ead78ad..b1cf1e1c0ce1 100644
--- a/drivers/infiniband/sw/rxe/rxe_param.h
+++ b/drivers/infiniband/sw/rxe/rxe_param.h
@@ -38,7 +38,7 @@ static inline enum ib_mtu eth_mtu_int_to_enum(int mtu)
  /* default/initial rxe device parameter settings */
  enum rxe_device_param {
         RXE_MAX_MR_SIZE                 = -1ull,
-       RXE_PAGE_SIZE_CAP               = 0xfffff000,
+       RXE_PAGE_SIZE_CAP               = 0xffffffff - (PAGE_SIZE - 1),
         RXE_MAX_QP_WR                   = DEFAULT_MAX_VALUE,
         RXE_DEVICE_CAP_FLAGS            = IB_DEVICE_BAD_PKEY_CNTR
                                         | IB_DEVICE_BAD_QKEY_CNTR


* minor cleanup will be done after this.

Thanks
Zhijian

> 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.
> 
> [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(-)
>