From: Long Li <[email protected]> Add code to post a receive request to RDMA. Before the SMB server can send a packet to SMB client via SMBD, a receive request must be posted to local RDMA layer.
Signed-off-by: Long Li <[email protected]> --- fs/cifs/cifsrdma.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/cifs/cifsrdma.h | 5 +++ 2 files changed, 129 insertions(+) diff --git a/fs/cifs/cifsrdma.c b/fs/cifs/cifsrdma.c index 8aa8a47..20237b7 100644 --- a/fs/cifs/cifsrdma.c +++ b/fs/cifs/cifsrdma.c @@ -62,6 +62,10 @@ static void put_receive_buffer( static int allocate_receive_buffers(struct cifs_rdma_info *info, int num_buf); static void destroy_receive_buffers(struct cifs_rdma_info *info); +static int cifs_rdma_post_recv( + struct cifs_rdma_info *info, + struct cifs_rdma_response *response); + /* * Per RDMA transport connection parameters * as defined in [MS-SMBD] 3.1.1.1 @@ -193,6 +197,85 @@ cifs_rdma_qp_async_error_upcall(struct ib_event *event, void *context) } } +/* Called from softirq, when recv is done */ +static void recv_done(struct ib_cq *cq, struct ib_wc *wc) +{ + struct smbd_data_transfer *data_transfer; + struct cifs_rdma_response *response = + container_of(wc->wr_cqe, struct cifs_rdma_response, cqe); + struct cifs_rdma_info *info = response->info; + + log_rdma_recv("response=%p type=%d wc status=%d wc opcode %d " + "byte_len=%d pkey_index=%x\n", + response, response->type, wc->status, wc->opcode, + wc->byte_len, wc->pkey_index); + + if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_RECV) { + log_rdma_recv("wc->status=%d opcode=%d\n", + wc->status, wc->opcode); + goto error; + } + + ib_dma_sync_single_for_cpu( + wc->qp->device, + response->sge.addr, + response->sge.length, + DMA_FROM_DEVICE); + + switch(response->type) { + case SMBD_TRANSFER_DATA: + data_transfer = (struct smbd_data_transfer *) response->packet; + atomic_dec(&info->receive_credits); + atomic_set(&info->receive_credit_target, + le16_to_cpu(data_transfer->credits_requested)); + atomic_add(le16_to_cpu(data_transfer->credits_granted), + &info->send_credits); + + log_incoming("data flags %d data_offset %d data_length %d " + "remaining_data_length %d\n", + le16_to_cpu(data_transfer->flags), + le32_to_cpu(data_transfer->data_offset), + le32_to_cpu(data_transfer->data_length), + le32_to_cpu(data_transfer->remaining_data_length)); + + log_transport_credit(info); + + // process sending queue on new credits + if (atomic_read(&info->send_credits)) + wake_up(&info->wait_send_queue); + + // process receive queue + if (le32_to_cpu(data_transfer->data_length)) { + if (info->full_packet_received) { + response->first_segment = true; + } + + if (le32_to_cpu(data_transfer->remaining_data_length)) + info->full_packet_received = false; + else + info->full_packet_received = true; + + goto queue_done; + } + + // if we reach here, this is an empty packet, finish it + break; + + default: + log_rdma_recv("unexpected response type=%d\n", response->type); + } + +error: + put_receive_buffer(info, response); + +queue_done: + if (atomic_dec_and_test(&info->recv_pending)) { + wake_up(&info->wait_recv_pending); + } + + return; +} + static struct rdma_cm_id* cifs_rdma_create_id( struct cifs_rdma_info *info, struct sockaddr *dstaddr) { @@ -289,6 +372,44 @@ static int cifs_rdma_ia_open( } /* + * Post a receive request to the transport + * The remote peer can only send data when a receive is posted + * The interaction is controlled by send/recieve credit system + */ +static int cifs_rdma_post_recv(struct cifs_rdma_info *info, struct cifs_rdma_response *response) +{ + struct ib_recv_wr recv_wr, *recv_wr_fail=NULL; + int rc = -EIO; + + response->sge.addr = ib_dma_map_single(info->id->device, response->packet, + info->max_receive_size, DMA_FROM_DEVICE); + if (ib_dma_mapping_error(info->id->device, response->sge.addr)) + return rc; + + response->sge.length = info->max_receive_size; + response->sge.lkey = info->pd->local_dma_lkey; + + response->cqe.done = recv_done; + + recv_wr.wr_cqe = &response->cqe; + recv_wr.next = NULL; + recv_wr.sg_list = &response->sge; + recv_wr.num_sge = 1; + + atomic_inc(&info->recv_pending); + rc = ib_post_recv(info->id->qp, &recv_wr, &recv_wr_fail); + if (rc) { + ib_dma_unmap_single(info->id->device, response->sge.addr, + response->sge.length, DMA_FROM_DEVICE); + + log_rdma_recv("ib_post_recv failed rc=%d\n", rc); + atomic_dec(&info->recv_pending); + } + + return rc; +} + +/* * Receive buffer operations. * For each remote send, we need to post a receive. The receive buffers are * pre-allocated in advance. @@ -485,6 +606,9 @@ struct cifs_rdma_info* cifs_create_rdma_session( allocate_receive_buffers(info, info->receive_credit_max); init_waitqueue_head(&info->wait_send_queue); + + init_waitqueue_head(&info->wait_recv_pending); + atomic_set(&info->recv_pending, 0); out2: rdma_destroy_id(info->id); diff --git a/fs/cifs/cifsrdma.h b/fs/cifs/cifsrdma.h index 287b5b1..8702a2b 100644 --- a/fs/cifs/cifsrdma.h +++ b/fs/cifs/cifsrdma.h @@ -59,6 +59,9 @@ struct cifs_rdma_info { atomic_t receive_credits; atomic_t receive_credit_target; + atomic_t recv_pending; + wait_queue_head_t wait_recv_pending; + struct list_head receive_queue; spinlock_t receive_queue_lock; @@ -68,6 +71,8 @@ struct cifs_rdma_info { struct kmem_cache *request_cache; mempool_t *request_mempool; + bool full_packet_received; + // response pool for RDMA receive struct kmem_cache *response_cache; mempool_t *response_mempool; -- 2.7.4
