Re: [PATCH] RDMA/rxe: Fix parameter errors

[Bob Pearson <rpearsonhpe@gmail.com>]

On 1/19/23 13:18, Jason Gunthorpe wrote:
> On Thu, Jan 19, 2023 at 12:05:07PM -0600, Bob Pearson wrote:
>> Correct errors in rxe_param.h caused by extending the range of
>> indices for MRs allowing it to overlap the range for MWs. Since
>> the driver determines whether an rkey is for an MR or MW by comparing
>> the index part of the rkey with these ranges this can cause an
>> MR to be incorrectly determined to be an MW.
>>
>> Additionally the parameters which determine the size of the index
>> ranges for MR, MW, QP and SRQ are incorrect since the actual
>> number of integers in the range [min, max] is (max - min + 1) not
>> (max - min).
>>
>> This patch corrects these errors.
>>
>> Fixes: 0994a1bcd5f7 ("RDMA/rxe: Bump up default maximum values used via uverbs")
>> Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
>> ---
>>  drivers/infiniband/sw/rxe/rxe_param.h | 27 +++++++++++++++++++--------
>>  1 file changed, 19 insertions(+), 8 deletions(-)
> 
> This
> 
> commit 1aefe5c177c1922119afb4ee443ddd6ac3140b37
> Author: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
> Date:   Tue Dec 20 17:08:48 2022 +0900
> 
>     RDMA/rxe: Prevent faulty rkey generation
>     
>     If you create MRs more than 0x10000 times after loading the module,
>     responder starts to reply NAKs for RDMA/Atomic operations because of rkey
>     violation detected in check_rkey(). The root cause is that rkeys are
>     incremented each time a new MR is created and the value overflows into the
>     range reserved for MWs.
>     
>     This commit also increases the value of RXE_MAX_MW that has been limited
>     unlike other parameters.
>     
>     Fixes: 0994a1bcd5f7 ("RDMA/rxe: Bump up default maximum values used via uverbs")
>     Link: https://lore.kernel.org/r/20221220080848.253785-2-matsuda-daisuke@fujitsu.com
>     Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
>     Tested-by: Li Zhijian <lizhijian@fujitsu.com>
>     Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
>     Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> 
> 
> Is already in v6.2-rc and conflicts with this patch, it looks like it
> is doing the same thing, can you sort it out please?
> 
> Thanks,
> Jason

Missed that one. Yes, they are basically identical except he cut the range in half and gave one to each and I doubled it. The other change I made is still a bug but much less important. It reports an incorrect max_xxx number in hca attributes but has no ill effect.
We can leave it the way it is for now.

Bob