Re: [PATCH] IB/rxe: Don't clamp residual length to mtu

Johannes Thumshirn
2017-04-25T07:29:52Z

On Thu, Apr 06, 2017 at 02:49:44PM +0200, Johannes Thumshirn wrote:
> When reading a RDMA WRITE FIRST packet we copy the DMA length from the RDMA
> header into the qp->resp.resid variable for later use. Later in check_rkey()
> we clamp it to the MTU if the packet is an RDMA WRITE packet and has a
> residual length bigger than the MTU. Later in write_data_in() we subtract the
> payload of the packet from the residual length. If the packet happens to have a
> payload of exactly the MTU size we end up with a residual length of 0 despite
> the packet not being the last in the conversation. When the next packet in the
> conversation arrives, we don't have any residual length left and thus set the QP
> into an error state.
>
> This broke NVMe over Fabrics functionality over rdma_rxe.ko
>
> The patch was verified using the following test.
>
> # echo eth0 > /sys/module/rdma_rxe/parameters/add
> # nvme connect -t rdma -a 192.168.155.101 -s 1023 -n nvmf-test
> # mkfs.xfs -fK /dev/nvme0n1
> meta-data=/dev/nvme0n1 isize=256 agcount=4, agsize=65536 blks
> = sectsz=4096 attr=2, projid32bit=1
> = crc=0 finobt=0, sparse=0
> data = bsize=4096 blocks=262144, imaxpct=25
> = sunit=0 swidth=0 blks
> naming =version 2 bsize=4096 ascii-ci=0 ftype=1
> log =internal log bsize=4096 blocks=2560, version=2
> = sectsz=4096 sunit=1 blks, lazy-count=1
> realtime =none extsz=4096 blocks=0, rtextents=0
> # mount /dev/nvme0n1 /tmp/
> [ 148.923263] XFS (nvme0n1): Mounting V4 Filesystem
> [ 148.961196] XFS (nvme0n1): Ending clean mount
> # dd if=/dev/urandom of=test.bin bs=1M count=128
> 128+0 records in
> 128+0 records out
> 134217728 bytes (134 MB, 128 MiB) copied, 0.437991 s, 306 MB/s
> # sha256sum test.bin
> cde42941f045efa8c4f0f157ab6f29741753cdd8d1cff93a6b03649d83c4129a test.bin
> # cp test.bin /tmp/
> sha256sum /tmp/test.bin
> cde42941f045efa8c4f0f157ab6f29741753cdd8d1cff93a6b03649d83c4129a /tmp/test.bin
>
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Sagi Grimberg <sagi@grimberg.me>
> Cc: Max Gurtovoy <maxg@mellanox.com>
> ---

Doug anything left here? I already have an Ack from Moni. This patch is needed
to get NVMe over Fabrics working on rxe so I'd like to see it in v4.12.

Thanks,
Johannes

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Johannes Thumshirn Storage
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