Re: [PATCH v2 1/8] IB/SRP: Avoid using IB_MR_TYPE_SG_GAPS

[Leon Romanovsky <leonro@mellanox.com>]

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On Wed, Feb 15, 2017 at 09:14:49AM +0200, Leon Romanovsky wrote:
> On Tue, Feb 14, 2017 at 10:56:29AM -0800, Bart Van Assche wrote:
> > Tests have shown that the following error message is reported when
> > using SG-GAPS registration with an mlx5 adapter:
> >
> > scsi host1: ib_srp: failed RECV status WR flushed (5) for CQE ffff880bd4270eb0
> > 00000000 00000000 00000000 00000000
> > 00000000 00000000 00000000 00000000
> > 00000000 00000000 00000000 00000000
> > 00000000 0f007806 2500002a ad9fafd1
> > scsi host1: ib_srp: reconnect succeeded
> > mlx5_0:dump_cqe:262:(pid 7369): dump error cqe
> > 00000000 00000000 00000000 00000000
> > 00000000 00000000 00000000 00000000
> > 00000000 00000000 00000000 00000000
> > 00000000 0f007806 25000032 00105dd0
> > scsi host1: ib_srp: failed FAST REG status memory management operation error (6) for CQE ffff880b92860138
> >
> > Hence avoid using SG-GAPS memory registrations. Additionally,
> > always configure the blk_queue_virt_boundary() to avoid to trigger
> > a mapping failure when using adapters that support SG-GAPS (e.g.
> > mlx5).
>
> According to the error dump, we have an issue with max_page_list_len supplied and/or
> internal calculations from that value to the UMR byte count.

Hi Bart,

Do you mind to try your test on my branch rdma-next [1] with the following
fixup?

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 3c1f483d003f..3e59dce10d5e 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1045,8 +1045,9 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
 	for (pages_mapped = 0;
 	     pages_mapped < pages_to_map && !err;
 	     pages_mapped += pages_iter, idx += pages_iter) {
+		npages = min_t(int, pages_iter, pages_to_map - pages_mapped);
 		dma_sync_single_for_cpu(ddev, dma, size, DMA_TO_DEVICE);
-		npages = populate_xlt(mr, idx, pages_iter, xlt,
+		npages = populate_xlt(mr, idx, npages, xlt,
 				      page_shift, size, flags);

 		dma_sync_single_for_device(ddev, dma, size, DMA_TO_DEVICE);

[1] https://git.kernel.org/cgit/linux/kernel/git/leon/linux-rdma.git/log/?h=rdma-next

Thanks

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