On 7/20/22 05:50, Haris Iqbal wrote:
> On Wed, Jul 20, 2022 at 12:22 PM Li Zhijian <lizhijian@xxxxxxxxxxx> wrote:
>>
>> Below 2 commits will be reverted:
>> 8ff5f5d9d8cf ("RDMA/rxe: Prevent double freeing rxe_map_set()")
>> 647bf13ce944 ("RDMA/rxe: Create duplicate mapping tables for FMRs")
>>
>> The community has a few bug reports which pointed this commit at last.
>> Some proposals are raised up in the meantime but all of them have no
>> follow-up operation.
>>
>> The previous commit led the map_set of FMR to be not avaliable any more if
>> the MR is registered again after invalidating. Although the mentioned
>> patch try to fix a potential race in building/accessing the same table
>> for fast memory regions, it broke rnbd etc ULPs. Since the latter could
>> be worse, revert this patch.
>>
>> With previous commit, it's observed that a same MR in rnbd server will
>> trigger below code path:
>
> Looks Good. I tested the patch against rdma for-next and it solves the
> problem mentioned in the commit.
> One small nitpick. It should be rtrs, and not rnbd in the commit message.
>
> Feel free to add my,
>
> Tested-by: Md Haris Iqbal <haris.iqbal@xxxxxxxxx>
>
Li,
It has been a while since this was added. If I recall there was a problem in rnfs
that this was supposed to fix. It was also supposed to allow overlap of using the
previous mappings and the driver creating new ones. But it seems that most fmr
based ulps don't require it, maybe all. Before we do this we should make sure that
blktests, srp, lustre, rnfs, etc all work. Have these been tested?
Bob
