]> git.baikalelectronics.ru Git - kernel.git/commit
xprtrdma: Don't wake pending tasks until disconnect is done
authorChuck Lever <chuck.lever@oracle.com>
Wed, 19 Dec 2018 15:58:40 +0000 (10:58 -0500)
committerAnna Schumaker <Anna.Schumaker@Netapp.com>
Wed, 2 Jan 2019 17:05:16 +0000 (12:05 -0500)
commitc478af62bf4ce18740b0c7a424fb6481bd49a405
tree88b2ad9aab6ed364301bc5c2dbcf804de550423c
parentefe01b81a8f98a8f0ed662a8467a59d7d402c92e
xprtrdma: Don't wake pending tasks until disconnect is done

Transport disconnect processing does a "wake pending tasks" at
various points.

Suppose an RPC Reply is being processed. The RPC task that Reply
goes with is waiting on the pending queue. If a disconnect wake-up
happens before reply processing is done, that reply, even if it is
good, is thrown away, and the RPC has to be sent again.

This window apparently does not exist for socket transports because
there is a lock held while a reply is being received which prevents
the wake-up call until after reply processing is done.

To resolve this, all RPC replies being processed on an RPC-over-RDMA
transport have to complete before pending tasks are awoken due to a
transport disconnect.

Callers that already hold the transport write lock may invoke
->ops->close directly. Others use a generic helper that schedules
a close when the write lock can be taken safely.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
net/sunrpc/xprtrdma/backchannel.c
net/sunrpc/xprtrdma/svc_rdma_backchannel.c
net/sunrpc/xprtrdma/transport.c
net/sunrpc/xprtrdma/verbs.c
net/sunrpc/xprtrdma/xprt_rdma.h