[v2,5/8] IB/srp: reduce local coverage for command submission and EH

Commit Message

David Dillow Jan. 5, 2011, 8:35 p.m. UTC

None

Patch

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 6f36dbe..d320dd4 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -818,9 +818,24 @@  static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
 }
 
 /*
+ * Return an IU and possible credit to the free pool
+ */
+static void srp_put_tx_iu(struct srp_target_port *target, struct srp_iu *iu,
+			  enum srp_iu_type iu_type)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(target->scsi_host->host_lock, flags);
+	list_add(&iu->list, &target->free_tx);
+	if (iu_type != SRP_IU_RSP)
+		++target->req_lim;
+	spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+}
+
+/*
  * Must be called with target->scsi_host->host_lock held to protect
- * req_lim and free_tx.  Lock cannot be dropped between call here and
- * call to __srp_post_send().
+ * req_lim and free_tx.  If IU is not sent, it must be returned using
+ * srp_put_tx_iu().
  *
  * Note:
  * An upper limit for the number of allocated information units for each
@@ -843,26 +858,25 @@  static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target,
 		return NULL;
 
 	/* Initiator responses to target requests do not consume credits */
-	if (target->req_lim <= rsv && iu_type != SRP_IU_RSP) {
-		++target->zero_req_lim;
-		return NULL;
+	if (iu_type != SRP_IU_RSP) {
+		if (target->req_lim <= rsv) {
+			++target->zero_req_lim;
+			return NULL;
+		}
+
+		--target->req_lim;
 	}
 
 	iu = list_first_entry(&target->free_tx, struct srp_iu, list);
-	iu->type = iu_type;
+	list_del(&iu->list);
 	return iu;
 }
 
-/*
- * Must be called with target->scsi_host->host_lock held to protect
- * req_lim and free_tx.
- */
-static int __srp_post_send(struct srp_target_port *target,
-			   struct srp_iu *iu, int len)
+static int srp_post_send(struct srp_target_port *target,
+			 struct srp_iu *iu, int len)
 {
 	struct ib_sge list;
 	struct ib_send_wr wr, *bad_wr;
-	int ret = 0;
 
 	list.addr   = iu->dma;
 	list.length = len;
@@ -875,15 +889,7 @@  static int __srp_post_send(struct srp_target_port *target,
 	wr.opcode     = IB_WR_SEND;
 	wr.send_flags = IB_SEND_SIGNALED;
 
-	ret = ib_post_send(target->qp, &wr, &bad_wr);
-
-	if (!ret) {
-		list_del(&iu->list);
-		if (iu->type != SRP_IU_RSP)
-			--target->req_lim;
-	}
-
-	return ret;
+	return ib_post_send(target->qp, &wr, &bad_wr);
 }
 
 static int srp_post_recv(struct srp_target_port *target, struct srp_iu *iu)
@@ -953,34 +959,33 @@  static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
 static int srp_response_common(struct srp_target_port *target, s32 req_delta,
 			       void *rsp, int len)
 {
-	struct ib_device *dev;
+	struct ib_device *dev = target->srp_host->srp_dev->dev;
 	unsigned long flags;
 	struct srp_iu *iu;
-	int err = 1;
-
-	dev = target->srp_host->srp_dev->dev;
+	int err;
 
 	spin_lock_irqsave(target->scsi_host->host_lock, flags);
 	target->req_lim += req_delta;
-
 	iu = __srp_get_tx_iu(target, SRP_IU_RSP);
+	spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+
 	if (!iu) {
 		shost_printk(KERN_ERR, target->scsi_host, PFX
 			     "no IU available to send response\n");
-		goto out;
+		return 1;
 	}
 
 	ib_dma_sync_single_for_cpu(dev, iu->dma, len, DMA_TO_DEVICE);
 	memcpy(iu->buf, rsp, len);
 	ib_dma_sync_single_for_device(dev, iu->dma, len, DMA_TO_DEVICE);
 
-	err = __srp_post_send(target, iu, len);
-	if (err)
+	err = srp_post_send(target, iu, len);
+	if (err) {
 		shost_printk(KERN_ERR, target->scsi_host, PFX
 			     "unable to post response: %d\n", err);
+		srp_put_tx_iu(target, iu, SRP_IU_RSP);
+	}
 
-out:
-	spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
 	return err;
 }
 
@@ -1107,14 +1112,14 @@  static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
 	}
 }
 
-static int srp_queuecommand_lck(struct scsi_cmnd *scmnd,
-			    void (*done)(struct scsi_cmnd *))
+static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
 {
-	struct srp_target_port *target = host_to_target(scmnd->device->host);
+	struct srp_target_port *target = host_to_target(shost);
 	struct srp_request *req;
 	struct srp_iu *iu;
 	struct srp_cmd *cmd;
 	struct ib_device *dev;
+	unsigned long flags;
 	int len;
 
 	if (target->state == SRP_TARGET_CONNECTING)
@@ -1123,11 +1128,19 @@  static int srp_queuecommand_lck(struct scsi_cmnd *scmnd,
 	if (target->state == SRP_TARGET_DEAD ||
 	    target->state == SRP_TARGET_REMOVED) {
 		scmnd->result = DID_BAD_TARGET << 16;
-		done(scmnd);
+		scmnd->scsi_done(scmnd);
 		return 0;
 	}
 
+	spin_lock_irqsave(shost->host_lock, flags);
 	iu = __srp_get_tx_iu(target, SRP_IU_CMD);
+	if (iu) {
+		req = list_first_entry(&target->free_reqs, struct srp_request,
+				      list);
+		list_del(&req->list);
+	}
+	spin_unlock_irqrestore(shost->host_lock, flags);
+
 	if (!iu)
 		goto err;
 
@@ -1135,9 +1148,6 @@  static int srp_queuecommand_lck(struct scsi_cmnd *scmnd,
 	ib_dma_sync_single_for_cpu(dev, iu->dma, srp_max_iu_len,
 				   DMA_TO_DEVICE);
 
-	req = list_first_entry(&target->free_reqs, struct srp_request, list);
-
-	scmnd->scsi_done     = done;
 	scmnd->result        = 0;
 	scmnd->host_scribble = (void *) req;
 
@@ -1156,30 +1166,33 @@  static int srp_queuecommand_lck(struct scsi_cmnd *scmnd,
 	if (len < 0) {
 		shost_printk(KERN_ERR, target->scsi_host,
 			     PFX "Failed to map data\n");
-		goto err;
+		goto err_iu;
 	}
 
 	ib_dma_sync_single_for_device(dev, iu->dma, srp_max_iu_len,
 				      DMA_TO_DEVICE);
 
-	if (__srp_post_send(target, iu, len)) {
+	if (srp_post_send(target, iu, len)) {
 		shost_printk(KERN_ERR, target->scsi_host, PFX "Send failed\n");
 		goto err_unmap;
 	}
 
-	list_del(&req->list);
-
 	return 0;
 
 err_unmap:
 	srp_unmap_data(scmnd, target, req);
 
+err_iu:
+	srp_put_tx_iu(target, iu, SRP_IU_CMD);
+
+	spin_lock_irqsave(shost->host_lock, flags);
+	list_add(&req->list, &target->free_reqs);
+	spin_unlock_irqrestore(shost->host_lock, flags);
+
 err:
 	return SCSI_MLQUEUE_HOST_BUSY;
 }
 
-static DEF_SCSI_QCMD(srp_queuecommand)
-
 static int srp_alloc_iu_bufs(struct srp_target_port *target)
 {
 	int i;
@@ -1433,17 +1446,18 @@  static int srp_send_tsk_mgmt(struct srp_target_port *target,
 	struct srp_iu *iu;
 	struct srp_tsk_mgmt *tsk_mgmt;
 
-	spin_lock_irq(target->scsi_host->host_lock);
-
 	if (target->state == SRP_TARGET_DEAD ||
 	    target->state == SRP_TARGET_REMOVED)
-		goto out;
+		return -1;
 
 	init_completion(&target->tsk_mgmt_done);
 
+	spin_lock_irq(target->scsi_host->host_lock);
 	iu = __srp_get_tx_iu(target, SRP_IU_TSK_MGMT);
+	spin_unlock_irq(target->scsi_host->host_lock);
+
 	if (!iu)
-		goto out;
+		return -1;
 
 	ib_dma_sync_single_for_cpu(dev, iu->dma, sizeof *tsk_mgmt,
 				   DMA_TO_DEVICE);
@@ -1458,20 +1472,16 @@  static int srp_send_tsk_mgmt(struct srp_target_port *target,
 
 	ib_dma_sync_single_for_device(dev, iu->dma, sizeof *tsk_mgmt,
 				      DMA_TO_DEVICE);
-	if (__srp_post_send(target, iu, sizeof *tsk_mgmt))
-		goto out;
-
-	spin_unlock_irq(target->scsi_host->host_lock);
+	if (srp_post_send(target, iu, sizeof *tsk_mgmt)) {
+		srp_put_tx_iu(target, iu, SRP_IU_TSK_MGMT);
+		return -1;
+	}
 
 	if (!wait_for_completion_timeout(&target->tsk_mgmt_done,
 					 msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS)))
 		return -1;
 
 	return 0;
-
-out:
-	spin_unlock_irq(target->scsi_host->host_lock);
-	return -1;
 }
 
 static int srp_abort(struct scsi_cmnd *scmnd)
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 924d8e9..81686ee 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -168,7 +168,6 @@  struct srp_iu {
 	void		       *buf;
 	size_t			size;
 	enum dma_data_direction	direction;
-	enum srp_iu_type	type;
 };
 
 #endif /* IB_SRP_H */