[PATCH 4.17 097/220] xprtrdma: Return -ENOBUFS when no pages are available

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chuck Lever <chuck.lever@xxxxxxxxxx>

commit a8f688ec437dc2045cc8f0c89fe877d5803850da upstream.

The use of -EAGAIN in rpcrdma_convert_iovs() is a latent bug: the
transport never calls xprt_write_space() when more pages become
available. -ENOBUFS will trigger the correct "delay briefly and call
again" logic.

Fixes: 7a89f9c626e3 ("xprtrdma: Honor ->send_request API contract")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 4.8+
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/sunrpc/xprtrdma/rpc_rdma.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -230,7 +230,7 @@ rpcrdma_convert_iovs(struct rpcrdma_xprt
 			 */
 			*ppages = alloc_page(GFP_ATOMIC);
 			if (!*ppages)
-				return -EAGAIN;
+				return -ENOBUFS;
 		}
 		seg->mr_page = *ppages;
 		seg->mr_offset = (char *)page_base;