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authorChuck Lever <chuck.lever@oracle.com>2015-08-03 13:03:49 -0400
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2015-08-05 16:21:27 -0400
commit5457ced0b504b41afe9439a6533066dea2fc0e1a (patch)
treea609ee8cf9c21fe64975759d80471aa88d159ddd /net
parentb3221d6a53c44cd572a3a400abdd1e2a24bea587 (diff)
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xprtrdma: Account for RPC/RDMA header size when deciding to inline
When the size of the RPC message is near the inline threshold (1KB), the client would allow messages to be sent that were a few bytes too large. When marshaling RPC/RDMA requests, ensure the combined size of RPC/RDMA header and RPC header do not exceed the inline threshold. Endpoints typically reject RPC/RDMA messages that exceed the size of their receive buffers. The two server implementations I test with (Linux and Solaris) use receive buffers that are larger than the client’s inline threshold. Thus so far this has been benign, observed only by code inspection. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com> Tested-by: Devesh Sharma <devesh.sharma@avagotech.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/xprtrdma/rpc_rdma.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 8e9c56429ada..950b654bad80 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -71,6 +71,31 @@ static const char transfertypes[][12] = {
};
#endif
+/* The client can send a request inline as long as the RPCRDMA header
+ * plus the RPC call fit under the transport's inline limit. If the
+ * combined call message size exceeds that limit, the client must use
+ * the read chunk list for this operation.
+ */
+static bool rpcrdma_args_inline(struct rpc_rqst *rqst)
+{
+ unsigned int callsize = RPCRDMA_HDRLEN_MIN + rqst->rq_snd_buf.len;
+
+ return callsize <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst);
+}
+
+/* The client can't know how large the actual reply will be. Thus it
+ * plans for the largest possible reply for that particular ULP
+ * operation. If the maximum combined reply message size exceeds that
+ * limit, the client must provide a write list or a reply chunk for
+ * this request.
+ */
+static bool rpcrdma_results_inline(struct rpc_rqst *rqst)
+{
+ unsigned int repsize = RPCRDMA_HDRLEN_MIN + rqst->rq_rcv_buf.buflen;
+
+ return repsize <= RPCRDMA_INLINE_READ_THRESHOLD(rqst);
+}
+
/*
* Chunk assembly from upper layer xdr_buf.
*
@@ -409,7 +434,7 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
* a READ, then use write chunks to separate the file data
* into pages; otherwise use reply chunks.
*/
- if (rqst->rq_rcv_buf.buflen <= RPCRDMA_INLINE_READ_THRESHOLD(rqst))
+ if (rpcrdma_results_inline(rqst))
wtype = rpcrdma_noch;
else if (rqst->rq_rcv_buf.page_len == 0)
wtype = rpcrdma_replych;
@@ -432,7 +457,7 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
* implies the op is a write.
* TBD check NFSv4 setacl
*/
- if (rqst->rq_snd_buf.len <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst))
+ if (rpcrdma_args_inline(rqst))
rtype = rpcrdma_noch;
else if (rqst->rq_snd_buf.page_len == 0)
rtype = rpcrdma_areadch;