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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>
This commit is contained in:
Chuck Lever 2015-08-03 13:03:49 -04:00 committed by Anna Schumaker
parent b3221d6a53
commit 5457ced0b5
1 changed files with 27 additions and 2 deletions
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29
net/sunrpc/xprtrdma/rpc_rdma.c
View File

@ -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;