IB/srp: Make receive buffer handling more robust
The current strategy in ib_srp for posting receive buffers is: * Post one buffer after channel establishment. * Post one buffer before sending an SRP_CMD or SRP_TSK_MGMT to the target. As a result, only the first non-SRP_RSP information unit from the target will be processed. If that first information unit is an SRP_T_LOGOUT, it will be processed. On the other hand, if the initiator receives an SRP_CRED_REQ or SRP_AER_REQ before it receives a SRP_T_LOGOUT, the SRP_T_LOGOUT won't be processed. We can fix this inconsistency by changing the strategy for posting receive buffers to: * Post all receive buffers after channel establishment. * After a receive buffer has been consumed and processed, post it again. A side effect is that the ib_post_recv() call is moved out of the SCSI command processing path. Since __srp_post_recv() is not called directly any more, get rid of it and move the code directly into srp_post_recv(). Also, move srp_post_recv() up in the file to avoid a forward declaration. Signed-off-by: Bart Van Assche <bart.vanassche@gmail.com> Acked-by: David Dillow <dave@thedillows.org> Signed-off-by: Roland Dreier <rolandd@cisco.com>
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@ -811,6 +811,38 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
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return len;
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}
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static int srp_post_recv(struct srp_target_port *target)
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{
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unsigned long flags;
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struct srp_iu *iu;
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struct ib_sge list;
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struct ib_recv_wr wr, *bad_wr;
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unsigned int next;
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int ret;
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spin_lock_irqsave(target->scsi_host->host_lock, flags);
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next = target->rx_head & (SRP_RQ_SIZE - 1);
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wr.wr_id = next;
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iu = target->rx_ring[next];
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list.addr = iu->dma;
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list.length = iu->size;
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list.lkey = target->srp_host->srp_dev->mr->lkey;
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wr.next = NULL;
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wr.sg_list = &list;
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wr.num_sge = 1;
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ret = ib_post_recv(target->qp, &wr, &bad_wr);
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if (!ret)
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++target->rx_head;
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spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
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return ret;
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}
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static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
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{
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struct srp_request *req;
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@ -868,6 +900,7 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
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{
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struct ib_device *dev;
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struct srp_iu *iu;
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int res;
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u8 opcode;
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iu = target->rx_ring[wc->wr_id];
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@ -904,6 +937,11 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
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ib_dma_sync_single_for_device(dev, iu->dma, target->max_ti_iu_len,
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DMA_FROM_DEVICE);
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res = srp_post_recv(target);
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if (res != 0)
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shost_printk(KERN_ERR, target->scsi_host,
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PFX "Recv failed with error code %d\n", res);
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}
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static void srp_recv_completion(struct ib_cq *cq, void *target_ptr)
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@ -943,45 +981,6 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
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}
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}
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static int __srp_post_recv(struct srp_target_port *target)
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{
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struct srp_iu *iu;
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struct ib_sge list;
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struct ib_recv_wr wr, *bad_wr;
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unsigned int next;
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int ret;
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next = target->rx_head & (SRP_RQ_SIZE - 1);
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wr.wr_id = next;
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iu = target->rx_ring[next];
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list.addr = iu->dma;
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list.length = iu->size;
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list.lkey = target->srp_host->srp_dev->mr->lkey;
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wr.next = NULL;
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wr.sg_list = &list;
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wr.num_sge = 1;
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ret = ib_post_recv(target->qp, &wr, &bad_wr);
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if (!ret)
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++target->rx_head;
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return ret;
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}
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static int srp_post_recv(struct srp_target_port *target)
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{
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unsigned long flags;
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int ret;
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spin_lock_irqsave(target->scsi_host->host_lock, flags);
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ret = __srp_post_recv(target);
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spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
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return ret;
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}
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/*
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* Must be called with target->scsi_host->host_lock held to protect
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* req_lim and tx_head. Lock cannot be dropped between call here and
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@ -1091,11 +1090,6 @@ static int srp_queuecommand(struct scsi_cmnd *scmnd,
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goto err;
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}
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if (__srp_post_recv(target)) {
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shost_printk(KERN_ERR, target->scsi_host, PFX "Recv failed\n");
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goto err_unmap;
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}
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ib_dma_sync_single_for_device(dev, iu->dma, srp_max_iu_len,
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DMA_TO_DEVICE);
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@ -1238,6 +1232,7 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
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int attr_mask = 0;
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int comp = 0;
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int opcode = 0;
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int i;
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switch (event->event) {
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case IB_CM_REQ_ERROR:
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@ -1287,7 +1282,11 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
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if (target->status)
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break;
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target->status = srp_post_recv(target);
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for (i = 0; i < SRP_RQ_SIZE; i++) {
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target->status = srp_post_recv(target);
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if (target->status)
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break;
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}
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if (target->status)
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break;
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