xprtrdma: Release in-flight MRs on disconnect

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Dan Aloni reports that when a server disconnects abruptly, a few
memory regions are left DMA mapped. Over time this leak could pin
enough I/O resources to slow or even deadlock an NFS/RDMA client.

I found that if a transport disconnects before pending Send and
FastReg WRs can be posted, the to-be-registered MRs are stranded on
the req's rl_registered list and never released -- since they
weren't posted, there's no Send completion to DMA unmap them.

Reported-by: Dan Aloni <dan@kernelim.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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Chuck Lever 2020-08-17 11:19:26 -04:00 • committed by Anna Schumaker

parent d012a7190f

commit 5de55ce951

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net/sunrpc/xprtrdma/verbs.c

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