xprtrdma: Fix error handling in rpcrdma_prepare_msg_sges()

When this function fails, it needs to undo the DMA mappings it's
done so far. Otherwise these are leaked.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 24 insertions, 14 deletions

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 3c9255824d94..4f6c5395d198 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -511,6 +511,28 @@ rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
         return 0;
 }
 
+/**
+ * rpcrdma_unmap_sges - DMA-unmap Send buffers
+ * @ia: interface adapter (device)
+ * @req: req with possibly some SGEs to be DMA unmapped
+ *
+ */
+void
+rpcrdma_unmap_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
+{
+        struct ib_sge *sge;
+        unsigned int count;
+
+        /* The first two SGEs contain the transport header and
+         * the inline buffer. These are always left mapped so
+         * they can be cheaply re-used.
+         */
+        sge = &req->rl_send_sge[2];
+        for (count = req->rl_mapped_sges; count--; sge++)
+                ib_dma_unmap_page(ia->ri_device,
+                                  sge->addr, sge->length, DMA_TO_DEVICE);
+}
+
 /* Prepare the RPC-over-RDMA header SGE.
  */
 static bool
@@ -641,10 +663,12 @@ out:
         return true;
 
 out_mapping_overflow:
+        rpcrdma_unmap_sges(ia, req);
         pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
         return false;
 
 out_mapping_err:
+        rpcrdma_unmap_sges(ia, req);
         pr_err("rpcrdma: Send mapping error\n");
         return false;
 }
@@ -671,20 +695,6 @@ out_map:
         return false;
 }
 
-void
-rpcrdma_unmap_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
-{
-        struct ib_device *device = ia->ri_device;
-        struct ib_sge *sge;
-        int count;
-
-        sge = &req->rl_send_sge[2];
-        for (count = req->rl_mapped_sges; count--; sge++)
-                ib_dma_unmap_page(device, sge->addr, sge->length,
-                                  DMA_TO_DEVICE);
-        req->rl_mapped_sges = 0;
-}
-
 /**
  * rpcrdma_marshal_req - Marshal and send one RPC request
  * @r_xprt: controlling transport