diff options
| -rw-r--r-- | net/sunrpc/xprtrdma/rpc_rdma.c | 61 |
1 files changed, 33 insertions, 28 deletions
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index e3560c2e2271..d018eb7814e7 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -740,8 +740,16 @@ rpcrdma_count_chunks(struct rpcrdma_rep *rep, int wrchunk, __be32 **iptrp) return total_len; } -/* - * Scatter inline received data back into provided iov's. +/** + * rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs + * @rqst: controlling RPC request + * @srcp: points to RPC message payload in receive buffer + * @copy_len: remaining length of receive buffer content + * @pad: Write chunk pad bytes needed (zero for pure inline) + * + * The upper layer has set the maximum number of bytes it can + * receive in each component of rq_rcv_buf. These values are set in + * the head.iov_len, page_len, tail.iov_len, and buflen fields. */ static void rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) @@ -751,17 +759,19 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) struct page **ppages; int page_base; + /* The head iovec is redirected to the RPC reply message + * in the receive buffer, to avoid a memcopy. + */ + rqst->rq_rcv_buf.head[0].iov_base = srcp; + + /* The contents of the receive buffer that follow + * head.iov_len bytes are copied into the page list. + */ curlen = rqst->rq_rcv_buf.head[0].iov_len; - if (curlen > copy_len) { /* write chunk header fixup */ + if (curlen > copy_len) curlen = copy_len; - rqst->rq_rcv_buf.head[0].iov_len = curlen; - } - dprintk("RPC: %s: srcp 0x%p len %d hdrlen %d\n", __func__, srcp, copy_len, curlen); - - /* Shift pointer for first receive segment only */ - rqst->rq_rcv_buf.head[0].iov_base = srcp; srcp += curlen; copy_len -= curlen; @@ -798,28 +808,23 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) break; page_base = 0; } - } - if (copy_len && rqst->rq_rcv_buf.tail[0].iov_len) { - curlen = copy_len; - if (curlen > rqst->rq_rcv_buf.tail[0].iov_len) - curlen = rqst->rq_rcv_buf.tail[0].iov_len; - if (rqst->rq_rcv_buf.tail[0].iov_base != srcp) - memmove(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen); - dprintk("RPC: %s: tail srcp 0x%p len %d curlen %d\n", - __func__, srcp, copy_len, curlen); - rqst->rq_rcv_buf.tail[0].iov_len = curlen; - copy_len -= curlen; ++i; - } else - rqst->rq_rcv_buf.tail[0].iov_len = 0; - - if (pad) { - /* implicit padding on terminal chunk */ - unsigned char *p = rqst->rq_rcv_buf.tail[0].iov_base; - while (pad--) - p[rqst->rq_rcv_buf.tail[0].iov_len++] = 0; + /* Implicit padding for the last segment in a Write + * chunk is inserted inline at the front of the tail + * iovec. The upper layer ignores the content of + * the pad. Simply ensure inline content in the tail + * that follows the Write chunk is properly aligned. + */ + if (pad) + srcp -= pad; } + /* The tail iovec is redirected to the remaining data + * in the receive buffer, to avoid a memcopy. + */ + if (copy_len || pad) + rqst->rq_rcv_buf.tail[0].iov_base = srcp; + if (copy_len) dprintk("RPC: %s: %d bytes in" " %d extra segments (%d lost)\n", |