From: Bart Van Assche Date: Fri, 30 Jul 2010 10:59:05 +0000 (+0000) Subject: IB/srp: Make receive buffer handling more robust X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c996bb47bb419b7c2f75499e11750142775e5da9;p=linux-beck.git 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 Acked-by: David Dillow Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index 4675defb374c..ffdd2d181f65 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -811,6 +811,38 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target, return len; } +static int srp_post_recv(struct srp_target_port *target) +{ + unsigned long flags; + struct srp_iu *iu; + struct ib_sge list; + struct ib_recv_wr wr, *bad_wr; + unsigned int next; + int ret; + + spin_lock_irqsave(target->scsi_host->host_lock, flags); + + next = target->rx_head & (SRP_RQ_SIZE - 1); + wr.wr_id = next; + iu = target->rx_ring[next]; + + list.addr = iu->dma; + list.length = iu->size; + list.lkey = target->srp_host->srp_dev->mr->lkey; + + wr.next = NULL; + wr.sg_list = &list; + wr.num_sge = 1; + + ret = ib_post_recv(target->qp, &wr, &bad_wr); + if (!ret) + ++target->rx_head; + + spin_unlock_irqrestore(target->scsi_host->host_lock, flags); + + return ret; +} + static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp) { struct srp_request *req; @@ -868,6 +900,7 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc) { struct ib_device *dev; struct srp_iu *iu; + int res; u8 opcode; iu = target->rx_ring[wc->wr_id]; @@ -904,6 +937,11 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc) ib_dma_sync_single_for_device(dev, iu->dma, target->max_ti_iu_len, DMA_FROM_DEVICE); + + res = srp_post_recv(target); + if (res != 0) + shost_printk(KERN_ERR, target->scsi_host, + PFX "Recv failed with error code %d\n", res); } static void srp_recv_completion(struct ib_cq *cq, void *target_ptr) @@ -943,45 +981,6 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr) } } -static int __srp_post_recv(struct srp_target_port *target) -{ - struct srp_iu *iu; - struct ib_sge list; - struct ib_recv_wr wr, *bad_wr; - unsigned int next; - int ret; - - next = target->rx_head & (SRP_RQ_SIZE - 1); - wr.wr_id = next; - iu = target->rx_ring[next]; - - list.addr = iu->dma; - list.length = iu->size; - list.lkey = target->srp_host->srp_dev->mr->lkey; - - wr.next = NULL; - wr.sg_list = &list; - wr.num_sge = 1; - - ret = ib_post_recv(target->qp, &wr, &bad_wr); - if (!ret) - ++target->rx_head; - - return ret; -} - -static int srp_post_recv(struct srp_target_port *target) -{ - unsigned long flags; - int ret; - - spin_lock_irqsave(target->scsi_host->host_lock, flags); - ret = __srp_post_recv(target); - spin_unlock_irqrestore(target->scsi_host->host_lock, flags); - - return ret; -} - /* * Must be called with target->scsi_host->host_lock held to protect * req_lim and tx_head. Lock cannot be dropped between call here and @@ -1091,11 +1090,6 @@ static int srp_queuecommand(struct scsi_cmnd *scmnd, goto err; } - if (__srp_post_recv(target)) { - shost_printk(KERN_ERR, target->scsi_host, PFX "Recv failed\n"); - goto err_unmap; - } - ib_dma_sync_single_for_device(dev, iu->dma, srp_max_iu_len, DMA_TO_DEVICE); @@ -1238,6 +1232,7 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event) int attr_mask = 0; int comp = 0; int opcode = 0; + int i; switch (event->event) { case IB_CM_REQ_ERROR: @@ -1287,7 +1282,11 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event) if (target->status) break; - target->status = srp_post_recv(target); + for (i = 0; i < SRP_RQ_SIZE; i++) { + target->status = srp_post_recv(target); + if (target->status) + break; + } if (target->status) break;