tree b3c0f93863078281535f9822e2dcedd228d95bab
parent d012a7190fc1fd72ed48911e77ca97ba4521bccd
author Chuck Lever <chuck.lever@oracle.com> 1597677566 -0400
committer Anna Schumaker <Anna.Schumaker@Netapp.com> 1598470161 -0400

xprtrdma: Release in-flight MRs on disconnect

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>