aboutsummaryrefslogtreecommitdiffstats
path: root/net
diff options
context:
space:
mode:
authorChuck Lever <chuck.lever@oracle.com>2018-12-19 10:58:13 -0500
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2019-01-02 12:05:16 -0500
commite2f34e26710bfaa545a9d9cd0c70137406401467 (patch)
treed888bf12d1ce95d407bbd2511a73d2c326b26ef8 /net
parent594d1644cd59447f4fceb592448d5cd09eb09b5e (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>
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/xprtrdma/frwr_ops.c6
-rw-r--r--net/sunrpc/xprtrdma/verbs.c9
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);
}

Privacy Policy