[PATCH 2/2 v2] IB/mad: use CQ abstraction

[Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>]

Remove the local workqueue to process mad completions and use the CQ API
instead.

Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
Reviewed-by: Hal Rosenstock <hal-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Reviewed-by: Ira Weiny <ira.weiny-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/infiniband/core/mad.c      | 162 +++++++++++++------------------------
 drivers/infiniband/core/mad_priv.h |   2 +-
 2 files changed, 59 insertions(+), 105 deletions(-)

diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index cbe232a..9fa5bf3 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -61,18 +61,6 @@ MODULE_PARM_DESC(send_queue_size, "Size of send queue in number of work requests
 module_param_named(recv_queue_size, mad_recvq_size, int, 0444);
 MODULE_PARM_DESC(recv_queue_size, "Size of receive queue in number of work requests");
 
-/*
- * Define a limit on the number of completions which will be processed by the
- * worker thread in a single work item.  This ensures that other work items
- * (potentially from other users) are processed fairly.
- *
- * The number of completions was derived from the default queue sizes above.
- * We use a value which is double the larger of the 2 queues (receive @ 512)
- * but keep it fixed such that an increase in that value does not introduce
- * unfairness.
- */
-#define MAD_COMPLETION_PROC_LIMIT 1024
-
 static struct list_head ib_mad_port_list;
 static u32 ib_mad_client_id = 0;
 
@@ -96,6 +84,9 @@ static int add_nonoui_reg_req(struct ib_mad_reg_req *mad_reg_req,
 			      u8 mgmt_class);
 static int add_oui_reg_req(struct ib_mad_reg_req *mad_reg_req,
 			   struct ib_mad_agent_private *agent_priv);
+static bool ib_mad_send_error(struct ib_mad_port_private *port_priv,
+			      struct ib_wc *wc);
+static void ib_mad_send_done(struct ib_cq *cq, struct ib_wc *wc);
 
 /*
  * Returns a ib_mad_port_private structure or NULL for a device/port
@@ -701,12 +692,11 @@ static void snoop_recv(struct ib_mad_qp_info *qp_info,
 	spin_unlock_irqrestore(&qp_info->snoop_lock, flags);
 }
 
-static void build_smp_wc(struct ib_qp *qp,
-			 u64 wr_id, u16 slid, u16 pkey_index, u8 port_num,
-			 struct ib_wc *wc)
+static void build_smp_wc(struct ib_qp *qp, struct ib_cqe *cqe, u16 slid,
+		u16 pkey_index, u8 port_num, struct ib_wc *wc)
 {
 	memset(wc, 0, sizeof *wc);
-	wc->wr_id = wr_id;
+	wc->wr_cqe = cqe;
 	wc->status = IB_WC_SUCCESS;
 	wc->opcode = IB_WC_RECV;
 	wc->pkey_index = pkey_index;
@@ -844,7 +834,7 @@ static int handle_outgoing_dr_smp(struct ib_mad_agent_private *mad_agent_priv,
 	}
 
 	build_smp_wc(mad_agent_priv->agent.qp,
-		     send_wr->wr.wr_id, drslid,
+		     send_wr->wr.wr_cqe, drslid,
 		     send_wr->pkey_index,
 		     send_wr->port_num, &mad_wc);
 
@@ -1051,7 +1041,9 @@ struct ib_mad_send_buf * ib_create_send_mad(struct ib_mad_agent *mad_agent,
 
 	mad_send_wr->sg_list[1].lkey = mad_agent->qp->pd->local_dma_lkey;
 
-	mad_send_wr->send_wr.wr.wr_id = (unsigned long) mad_send_wr;
+	mad_send_wr->mad_list.cqe.done = ib_mad_send_done;
+
+	mad_send_wr->send_wr.wr.wr_cqe = &mad_send_wr->mad_list.cqe;
 	mad_send_wr->send_wr.wr.sg_list = mad_send_wr->sg_list;
 	mad_send_wr->send_wr.wr.num_sge = 2;
 	mad_send_wr->send_wr.wr.opcode = IB_WR_SEND;
@@ -1163,8 +1155,9 @@ int ib_send_mad(struct ib_mad_send_wr_private *mad_send_wr)
 
 	/* Set WR ID to find mad_send_wr upon completion */
 	qp_info = mad_send_wr->mad_agent_priv->qp_info;
-	mad_send_wr->send_wr.wr.wr_id = (unsigned long)&mad_send_wr->mad_list;
 	mad_send_wr->mad_list.mad_queue = &qp_info->send_queue;
+	mad_send_wr->mad_list.cqe.done = ib_mad_send_done;
+	mad_send_wr->send_wr.wr.wr_cqe = &mad_send_wr->mad_list.cqe;
 
 	mad_agent = mad_send_wr->send_buf.mad_agent;
 	sge = mad_send_wr->sg_list;
@@ -2185,13 +2178,14 @@ handle_smi(struct ib_mad_port_private *port_priv,
 	return handle_ib_smi(port_priv, qp_info, wc, port_num, recv, response);
 }
 
-static void ib_mad_recv_done_handler(struct ib_mad_port_private *port_priv,
-				     struct ib_wc *wc)
+static void ib_mad_recv_done(struct ib_cq *cq, struct ib_wc *wc)
 {
+	struct ib_mad_port_private *port_priv = cq->cq_context;
+	struct ib_mad_list_head *mad_list =
+		container_of(wc->wr_cqe, struct ib_mad_list_head, cqe);
 	struct ib_mad_qp_info *qp_info;
 	struct ib_mad_private_header *mad_priv_hdr;
 	struct ib_mad_private *recv, *response = NULL;
-	struct ib_mad_list_head *mad_list;
 	struct ib_mad_agent_private *mad_agent;
 	int port_num;
 	int ret = IB_MAD_RESULT_SUCCESS;
@@ -2199,7 +2193,17 @@ static void ib_mad_recv_done_handler(struct ib_mad_port_private *port_priv,
 	u16 resp_mad_pkey_index = 0;
 	bool opa;
 
-	mad_list = (struct ib_mad_list_head *)(unsigned long)wc->wr_id;
+	if (list_empty_careful(&port_priv->port_list))
+		return;
+
+	if (wc->status != IB_WC_SUCCESS) {
+		/*
+		 * Receive errors indicate that the QP has entered the error
+		 * state - error handling/shutdown code will cleanup
+		 */
+		return;
+	}
+
 	qp_info = mad_list->mad_queue->qp_info;
 	dequeue_mad(mad_list);
 
@@ -2240,7 +2244,7 @@ static void ib_mad_recv_done_handler(struct ib_mad_port_private *port_priv,
 	response = alloc_mad_private(mad_size, GFP_KERNEL);
 	if (!response) {
 		dev_err(&port_priv->device->dev,
-			"ib_mad_recv_done_handler no memory for response buffer\n");
+			"%s: no memory for response buffer\n", __func__);
 		goto out;
 	}
 
@@ -2426,11 +2430,12 @@ done:
 	spin_unlock_irqrestore(&mad_agent_priv->lock, flags);
 }
 
-static void ib_mad_send_done_handler(struct ib_mad_port_private *port_priv,
-				     struct ib_wc *wc)
+static void ib_mad_send_done(struct ib_cq *cq, struct ib_wc *wc)
 {
+	struct ib_mad_port_private *port_priv = cq->cq_context;
+	struct ib_mad_list_head *mad_list =
+		container_of(wc->wr_cqe, struct ib_mad_list_head, cqe);
 	struct ib_mad_send_wr_private	*mad_send_wr, *queued_send_wr;
-	struct ib_mad_list_head		*mad_list;
 	struct ib_mad_qp_info		*qp_info;
 	struct ib_mad_queue		*send_queue;
 	struct ib_send_wr		*bad_send_wr;
@@ -2438,7 +2443,14 @@ static void ib_mad_send_done_handler(struct ib_mad_port_private *port_priv,
 	unsigned long flags;
 	int ret;
 
-	mad_list = (struct ib_mad_list_head *)(unsigned long)wc->wr_id;
+	if (list_empty_careful(&port_priv->port_list))
+		return;
+
+	if (wc->status != IB_WC_SUCCESS) {
+		if (!ib_mad_send_error(port_priv, wc))
+			return;
+	}
+
 	mad_send_wr = container_of(mad_list, struct ib_mad_send_wr_private,
 				   mad_list);
 	send_queue = mad_list->mad_queue;
@@ -2503,24 +2515,15 @@ static void mark_sends_for_retry(struct ib_mad_qp_info *qp_info)
 	spin_unlock_irqrestore(&qp_info->send_queue.lock, flags);
 }
 
-static void mad_error_handler(struct ib_mad_port_private *port_priv,
-			      struct ib_wc *wc)
+static bool ib_mad_send_error(struct ib_mad_port_private *port_priv,
+		struct ib_wc *wc)
 {
-	struct ib_mad_list_head *mad_list;
-	struct ib_mad_qp_info *qp_info;
+	struct ib_mad_list_head *mad_list =
+		container_of(wc->wr_cqe, struct ib_mad_list_head, cqe);
+	struct ib_mad_qp_info *qp_info = mad_list->mad_queue->qp_info;
 	struct ib_mad_send_wr_private *mad_send_wr;
 	int ret;
 
-	/* Determine if failure was a send or receive */
-	mad_list = (struct ib_mad_list_head *)(unsigned long)wc->wr_id;
-	qp_info = mad_list->mad_queue->qp_info;
-	if (mad_list->mad_queue == &qp_info->recv_queue)
-		/*
-		 * Receive errors indicate that the QP has entered the error
-		 * state - error handling/shutdown code will cleanup
-		 */
-		return;
-
 	/*
 	 * Send errors will transition the QP to SQE - move
 	 * QP to RTS and repost flushed work requests
@@ -2535,10 +2538,9 @@ static void mad_error_handler(struct ib_mad_port_private *port_priv,
 			mad_send_wr->retry = 0;
 			ret = ib_post_send(qp_info->qp, &mad_send_wr->send_wr.wr,
 					&bad_send_wr);
-			if (ret)
-				ib_mad_send_done_handler(port_priv, wc);
-		} else
-			ib_mad_send_done_handler(port_priv, wc);
+			if (!ret)
+				return false;
+		}
 	} else {
 		struct ib_qp_attr *attr;
 
@@ -2552,48 +2554,14 @@ static void mad_error_handler(struct ib_mad_port_private *port_priv,
 			kfree(attr);
 			if (ret)
 				dev_err(&port_priv->device->dev,
-					"mad_error_handler - ib_modify_qp to RTS : %d\n",
-					ret);
+					"%s - ib_modify_qp to RTS: %d\n",
+					__func__, ret);
 			else
 				mark_sends_for_retry(qp_info);
 		}
-		ib_mad_send_done_handler(port_priv, wc);
 	}
-}
 
-/*
- * IB MAD completion callback
- */
-static void ib_mad_completion_handler(struct work_struct *work)
-{
-	struct ib_mad_port_private *port_priv;
-	struct ib_wc wc;
-	int count = 0;
-
-	port_priv = container_of(work, struct ib_mad_port_private, work);
-	ib_req_notify_cq(port_priv->cq, IB_CQ_NEXT_COMP);
-
-	while (ib_poll_cq(port_priv->cq, 1, &wc) == 1) {
-		if (wc.status == IB_WC_SUCCESS) {
-			switch (wc.opcode) {
-			case IB_WC_SEND:
-				ib_mad_send_done_handler(port_priv, &wc);
-				break;
-			case IB_WC_RECV:
-				ib_mad_recv_done_handler(port_priv, &wc);
-				break;
-			default:
-				BUG_ON(1);
-				break;
-			}
-		} else
-			mad_error_handler(port_priv, &wc);
-
-		if (++count > MAD_COMPLETION_PROC_LIMIT) {
-			queue_work(port_priv->wq, &port_priv->work);
-			break;
-		}
-	}
+	return true;
 }
 
 static void cancel_mads(struct ib_mad_agent_private *mad_agent_priv)
@@ -2735,7 +2703,7 @@ static void local_completions(struct work_struct *work)
 			 * before request
 			 */
 			build_smp_wc(recv_mad_agent->agent.qp,
-				     (unsigned long) local->mad_send_wr,
+				     local->mad_send_wr->send_wr.wr.wr_cqe,
 				     be16_to_cpu(IB_LID_PERMISSIVE),
 				     local->mad_send_wr->send_wr.pkey_index,
 				     recv_mad_agent->agent.port_num, &wc);
@@ -2875,17 +2843,6 @@ static void timeout_sends(struct work_struct *work)
 	spin_unlock_irqrestore(&mad_agent_priv->lock, flags);
 }
 
-static void ib_mad_thread_completion_handler(struct ib_cq *cq, void *arg)
-{
-	struct ib_mad_port_private *port_priv = cq->cq_context;
-	unsigned long flags;
-
-	spin_lock_irqsave(&ib_mad_port_list_lock, flags);
-	if (!list_empty(&port_priv->port_list))
-		queue_work(port_priv->wq, &port_priv->work);
-	spin_unlock_irqrestore(&ib_mad_port_list_lock, flags);
-}
-
 /*
  * Allocate receive MADs and post receive WRs for them
  */
@@ -2933,8 +2890,9 @@ static int ib_mad_post_receive_mads(struct ib_mad_qp_info *qp_info,
 			break;
 		}
 		mad_priv->header.mapping = sg_list.addr;
-		recv_wr.wr_id = (unsigned long)&mad_priv->header.mad_list;
 		mad_priv->header.mad_list.mad_queue = recv_queue;
+		mad_priv->header.mad_list.cqe.done = ib_mad_recv_done;
+		recv_wr.wr_cqe = &mad_priv->header.mad_list.cqe;
 
 		/* Post receive WR */
 		spin_lock_irqsave(&recv_queue->lock, flags);
@@ -3171,7 +3129,6 @@ static int ib_mad_port_open(struct ib_device *device,
 	unsigned long flags;
 	char name[sizeof "ib_mad123"];
 	int has_smi;
-	struct ib_cq_init_attr cq_attr = {};
 
 	if (WARN_ON(rdma_max_mad_size(device, port_num) < IB_MGMT_MAD_SIZE))
 		return -EFAULT;
@@ -3199,10 +3156,8 @@ static int ib_mad_port_open(struct ib_device *device,
 	if (has_smi)
 		cq_size *= 2;
 
-	cq_attr.cqe = cq_size;
-	port_priv->cq = ib_create_cq(port_priv->device,
-				     ib_mad_thread_completion_handler,
-				     NULL, port_priv, &cq_attr);
+	port_priv->cq = ib_alloc_cq(port_priv->device, port_priv, cq_size, 0,
+			IB_POLL_WORKQUEUE);
 	if (IS_ERR(port_priv->cq)) {
 		dev_err(&device->dev, "Couldn't create ib_mad CQ\n");
 		ret = PTR_ERR(port_priv->cq);
@@ -3231,7 +3186,6 @@ static int ib_mad_port_open(struct ib_device *device,
 		ret = -ENOMEM;
 		goto error8;
 	}
-	INIT_WORK(&port_priv->work, ib_mad_completion_handler);
 
 	spin_lock_irqsave(&ib_mad_port_list_lock, flags);
 	list_add_tail(&port_priv->port_list, &ib_mad_port_list);
@@ -3258,7 +3212,7 @@ error7:
 error6:
 	ib_dealloc_pd(port_priv->pd);
 error4:
-	ib_destroy_cq(port_priv->cq);
+	ib_free_cq(port_priv->cq);
 	cleanup_recv_queue(&port_priv->qp_info[1]);
 	cleanup_recv_queue(&port_priv->qp_info[0]);
 error3:
@@ -3291,7 +3245,7 @@ static int ib_mad_port_close(struct ib_device *device, int port_num)
 	destroy_mad_qp(&port_priv->qp_info[1]);
 	destroy_mad_qp(&port_priv->qp_info[0]);
 	ib_dealloc_pd(port_priv->pd);
-	ib_destroy_cq(port_priv->cq);
+	ib_free_cq(port_priv->cq);
 	cleanup_recv_queue(&port_priv->qp_info[1]);
 	cleanup_recv_queue(&port_priv->qp_info[0]);
 	/* XXX: Handle deallocation of MAD registration tables */
diff --git a/drivers/infiniband/core/mad_priv.h b/drivers/infiniband/core/mad_priv.h
index 990698a..28669f6 100644
--- a/drivers/infiniband/core/mad_priv.h
+++ b/drivers/infiniband/core/mad_priv.h
@@ -64,6 +64,7 @@
 
 struct ib_mad_list_head {
 	struct list_head list;
+	struct ib_cqe cqe;
 	struct ib_mad_queue *mad_queue;
 };
 
@@ -204,7 +205,6 @@ struct ib_mad_port_private {
 	struct ib_mad_mgmt_version_table version[MAX_MGMT_VERSION];
 	struct list_head agent_list;
 	struct workqueue_struct *wq;
-	struct work_struct work;
 	struct ib_mad_qp_info qp_info[IB_MAD_QPS_CORE];
 };
 
-- 
1.9.1

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