/*
* Set up the rqstp thread context to point to the RQ buffer. If
* necessary, pull additional data from the client with an RDMA_READ
* request.
*/
int svc_rdma_recvfrom(struct svc_rqst *rqstp)
{
struct svc_xprt *xprt = rqstp->rq_xprt;
struct svcxprt_rdma *rdma_xprt =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
struct svc_rdma_op_ctxt *ctxt = NULL;
struct rpcrdma_msg *rmsgp;
int ret = 0;
dprintk("svcrdma: rqstp=%p\n", rqstp);
spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
struct svc_rdma_op_ctxt,
dto_q);
list_del_init(&ctxt->dto_q);
spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
return rdma_read_complete(rqstp, ctxt);
} else if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
/**
* svc_rdma_recvfrom - Receive an RPC call
* @rqstp: request structure into which to receive an RPC Call
*
* Returns:
* The positive number of bytes in the RPC Call message,
* %0 if there were no Calls ready to return,
* %-EINVAL if the Read chunk data is too large,
* %-ENOMEM if rdma_rw context pool was exhausted,
* %-ENOTCONN if posting failed (connection is lost),
* %-EIO if rdma_rw initialization failed (DMA mapping, etc).
*
* Called in a loop when XPT_DATA is set. XPT_DATA is cleared only
* when there are no remaining ctxt's to process.
*
* The next ctxt is removed from the "receive" lists.
*
* - If the ctxt completes a Read, then finish assembling the Call
* message and return the number of bytes in the message.
*
* - If the ctxt completes a Receive, then construct the Call
* message from the contents of the Receive buffer.
*
* - If there are no Read chunks in this message, then finish
* assembling the Call message and return the number of bytes
* in the message.
*
* - If there are Read chunks in this message, post Read WRs to
* pull that payload and return 0.
*/
int svc_rdma_recvfrom(struct svc_rqst *rqstp)
{
struct svc_xprt *xprt = rqstp->rq_xprt;
struct svcxprt_rdma *rdma_xprt =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
struct svc_rdma_recv_ctxt *ctxt;
__be32 *p;
int ret;
spin_lock(&rdma_xprt->sc_rq_dto_lock);
ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_read_complete_q);
if (ctxt) {
list_del(&ctxt->rc_list);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
rdma_read_complete(rqstp, ctxt);
goto complete;
}
ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q);
if (!ctxt) {
/* No new incoming requests, terminate the loop */
clear_bit(XPT_DATA, &xprt->xpt_flags);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
return 0;
}
list_del(&ctxt->rc_list);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
atomic_inc(&rdma_stat_recv);
svc_rdma_build_arg_xdr(rqstp, ctxt);
/* Prevent svc_xprt_release from releasing pages in rq_pages
* if we return 0 or an error.
*/
rqstp->rq_respages = rqstp->rq_pages;
rqstp->rq_next_page = rqstp->rq_respages;
p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg);
if (ret < 0)
goto out_err;
if (ret == 0)
goto out_drop;
rqstp->rq_xprt_hlen = ret;
if (svc_rdma_is_backchannel_reply(xprt, p)) {
ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt, p,
&rqstp->rq_arg);
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
return ret;
}
svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
p += rpcrdma_fixed_maxsz;
if (*p != xdr_zero)
goto out_readchunk;
complete:
rqstp->rq_xprt_ctxt = ctxt;
rqstp->rq_prot = IPPROTO_MAX;
svc_xprt_copy_addrs(rqstp, xprt);
return rqstp->rq_arg.len;
out_readchunk:
ret = svc_rdma_recv_read_chunk(rdma_xprt, rqstp, ctxt, p);
if (ret < 0)
goto out_postfail;
return 0;
out_err:
svc_rdma_send_error(rdma_xprt, p, ret);
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
return 0;
out_postfail:
if (ret == -EINVAL)
svc_rdma_send_error(rdma_xprt, p, ret);
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
return ret;
out_drop:
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
return 0;
}