> >> Moving the QP into error state right after with rdma_disconnect > >> you are not sure that none of the subset of the invalidations > >> that _were_ posted completed and you get the corresponding MRs > >> in a bogus state... > > > > Moving the QP to error state and then draining the CQs means > > that all LOCAL_INV WRs that managed to get posted will get > > completed or flushed. That's already handled today. > > > > It's the WRs that didn't get posted that I'm worried about > > in this patch. > > > > Are there RDMA consumers in the kernel that use that third > > argument to recover when LOCAL_INV WRs cannot be posted? > > None :) > > >>> I suppose I could reset these MRs instead (that is, > >>> pass them to ib_dereg_mr). > >> > >> Or, just wait for a completion for those that were posted > >> and then all the MRs are in a consistent state. > > > > When a LOCAL_INV completes with IB_WC_SUCCESS, the associated > > MR is in a known state (ie, invalid). > > > > The WRs that flush mean the associated MRs are not in a known > > state. Sometimes the MR state is different than the hardware > > state, for example. Trying to do anything with one of these > > inconsistent MRs results in IB_WC_BIND_MW_ERR until the thing > > is deregistered. > > Correct. > It is legal to invalidate an MR that is not in the valid state. So you don't have to deregister it, you can assume it is valid and post another LINV WR. > > The xprtrdma completion handlers mark the MR associated with > > a flushed LOCAL_INV WR "stale". They all have to be reset with > > ib_dereg_mr to guarantee they are usable again. Have a look at > > __frwr_recovery_worker(). > > Yes, I'm aware of that. > > > And, xprtrdma waits for only the last LOCAL_INV in the chain to > > complete. If that one isn't posted, then fr_done is never woken > > up. In that case, frwr_op_unmap_sync() would wait forever. > > Ah.. so the (missing) completions is the problem, now I get > it. > > > If I understand you I think the correct solution is for > > frwr_op_unmap_sync() to regroup and reset the MRs associated > > with the LOCAL_INV WRs that were never posted, using the same > > mechanism as __frwr_recovery_worker() . > > Yea, I'd recycle all the MRs instead of having non-trivial logic > to try and figure out MR states... > > > It's already 4.5-rc7, a little late for a significant rework > > of this patch, so maybe I should drop it? > > Perhaps... Although you can make it incremental because the current > patch doesn't seem to break anything, just not solving the complete > problem... > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
