diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2018-12-19 10:58:13 -0500 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2019-01-02 12:05:16 -0500 |
| commit | e2f34e26710bfaa545a9d9cd0c70137406401467 (patch) | |
| tree | d888bf12d1ce95d407bbd2511a73d2c326b26ef8 | |
| parent | 594d1644cd59447f4fceb592448d5cd09eb09b5e (diff) | |
xprtrdma: Yet another double DMA-unmap
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>
| -rw-r--r-- | net/sunrpc/xprtrdma/frwr_ops.c | 6 | ||||
| -rw-r--r-- | net/sunrpc/xprtrdma/verbs.c | 9 |
2 files changed, 10 insertions, 5 deletions
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c index fc6378cc0c1c..20ced24cc61b 100644 --- a/net/sunrpc/xprtrdma/frwr_ops.c +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -117,15 +117,15 @@ static void frwr_mr_recycle_worker(struct work_struct *work) { struct rpcrdma_mr *mr = container_of(work, struct rpcrdma_mr, mr_recycle); - enum rpcrdma_frwr_state state = mr->frwr.fr_state; struct rpcrdma_xprt *r_xprt = mr->mr_xprt; trace_xprtrdma_mr_recycle(mr); - if (state != FRWR_FLUSHED_LI) { + if (mr->mr_dir != DMA_NONE) { trace_xprtrdma_mr_unmap(mr); ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, mr->mr_sg, mr->mr_nents, mr->mr_dir); + mr->mr_dir = DMA_NONE; } spin_lock(&r_xprt->rx_buf.rb_mrlock); @@ -150,6 +150,8 @@ frwr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr) if (!mr->mr_sg) goto out_list_err; + frwr->fr_state = FRWR_IS_INVALID; + mr->mr_dir = DMA_NONE; INIT_LIST_HEAD(&mr->mr_list); INIT_WORK(&mr->mr_recycle, frwr_mr_recycle_worker); sg_init_table(mr->mr_sg, depth); diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 3ddba94c939f..b9bc7f9f6bb9 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1329,9 +1329,12 @@ rpcrdma_mr_unmap_and_put(struct rpcrdma_mr *mr) { struct rpcrdma_xprt *r_xprt = mr->mr_xprt; - trace_xprtrdma_mr_unmap(mr); - ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, - mr->mr_sg, mr->mr_nents, mr->mr_dir); + if (mr->mr_dir != DMA_NONE) { + trace_xprtrdma_mr_unmap(mr); + ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, + mr->mr_sg, mr->mr_nents, mr->mr_dir); + mr->mr_dir = DMA_NONE; + } __rpcrdma_mr_put(&r_xprt->rx_buf, mr); } |