xprtrdma: Yet another double DMA-unmap

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While chasing yet another set of DMAR fault reports, I noticed that
the frwr recycler conflates whether or not an MR has been DMA
unmapped with frwr->fr_state. Actually the two have only an indirect
relationship. It's in fact impossible to guess reliably whether the
MR has been DMA unmapped based on its fr_state field, especially as
the surrounding code and its assumptions have changed over time.

A better approach is to track the DMA mapping status explicitly so
that the recycler is less brittle to unexpected situations, and
attempts to DMA-unmap a second time are prevented.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org # v4.20
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

...

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Chuck Lever 2018-12-19 10:58:13 -05:00 • committed by Anna Schumaker

parent 594d1644cd

commit e2f34e2671

2 changed files with 10 additions and 5 deletions

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6

net/sunrpc/xprtrdma/frwr_ops.c

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9

net/sunrpc/xprtrdma/verbs.c

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