[PATCH for-next 06/16] RDMA/rxe: Make task interface pluggable

[Bob Pearson <rpearsonhpe@gmail.com>]

Make the internal interface to the task operations pluggable and
add a new 'inline' type.

Signed-off-by: Ian Ziemba <ian.ziemba@hpe.com>
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_qp.c   |   8 +-
 drivers/infiniband/sw/rxe/rxe_task.c | 160 ++++++++++++++++++++++-----
 drivers/infiniband/sw/rxe/rxe_task.h |  44 +++++---
 3 files changed, 165 insertions(+), 47 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
index 3f6d62a80bea..b5e108794aa1 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -238,8 +238,10 @@ static int rxe_qp_init_req(struct rxe_dev *rxe, struct rxe_qp *qp,
 
 	skb_queue_head_init(&qp->req_pkts);
 
-	rxe_init_task(&qp->req.task, qp, rxe_requester);
-	rxe_init_task(&qp->comp.task, qp, rxe_completer);
+	rxe_init_task(&qp->req.task, qp, rxe_requester, RXE_TASK_TYPE_TASKLET);
+	rxe_init_task(&qp->comp.task, qp, rxe_completer,
+			(qp_type(qp) == IB_QPT_RC) ? RXE_TASK_TYPE_TASKLET :
+						     RXE_TASK_TYPE_INLINE);
 
 	qp->qp_timeout_jiffies = 0; /* Can't be set for UD/UC in modify_qp */
 	if (init->qp_type == IB_QPT_RC) {
@@ -286,7 +288,7 @@ static int rxe_qp_init_resp(struct rxe_dev *rxe, struct rxe_qp *qp,
 
 	skb_queue_head_init(&qp->resp_pkts);
 
-	rxe_init_task(&qp->resp.task, qp, rxe_responder);
+	rxe_init_task(&qp->resp.task, qp, rxe_responder, RXE_TASK_TYPE_TASKLET);
 
 	qp->resp.opcode		= OPCODE_NONE;
 	qp->resp.msn		= 0;
diff --git a/drivers/infiniband/sw/rxe/rxe_task.c b/drivers/infiniband/sw/rxe/rxe_task.c
index 42442ede99e8..fcd87114949f 100644
--- a/drivers/infiniband/sw/rxe/rxe_task.c
+++ b/drivers/infiniband/sw/rxe/rxe_task.c
@@ -28,12 +28,11 @@ int __rxe_do_task(struct rxe_task *task)
  * a second caller finds the task already running
  * but looks just after the last call to func
  */
-static void do_task(struct tasklet_struct *t)
+static void do_task(struct rxe_task *task)
 {
+	unsigned int iterations = RXE_MAX_ITERATIONS;
 	int cont;
 	int ret;
-	struct rxe_task *task = from_tasklet(task, t, tasklet);
-	unsigned int iterations = RXE_MAX_ITERATIONS;
 
 	spin_lock_bh(&task->lock);
 	switch (task->state) {
@@ -94,28 +93,21 @@ static void do_task(struct tasklet_struct *t)
 	task->ret = ret;
 }
 
-int rxe_init_task(struct rxe_task *task, void *arg, int (*func)(void *))
+static void disable_task(struct rxe_task *task)
 {
-	task->arg	= arg;
-	task->func	= func;
-	task->destroyed	= false;
-
-	tasklet_setup(&task->tasklet, do_task);
-
-	task->state = TASK_STATE_START;
-	spin_lock_init(&task->lock);
+	/* todo */
+}
 
-	return 0;
+static void enable_task(struct rxe_task *task)
+{
+	/* todo */
 }
 
-void rxe_cleanup_task(struct rxe_task *task)
+/* busy wait until any previous tasks are done */
+static void cleanup_task(struct rxe_task *task)
 {
 	bool idle;
 
-	/*
-	 * Mark the task, then wait for it to finish. It might be
-	 * running in a non-tasklet (direct call) context.
-	 */
 	task->destroyed = true;
 
 	do {
@@ -123,32 +115,144 @@ void rxe_cleanup_task(struct rxe_task *task)
 		idle = (task->state == TASK_STATE_START);
 		spin_unlock_bh(&task->lock);
 	} while (!idle);
+}
 
-	tasklet_kill(&task->tasklet);
+/* silently treat schedule as inline for inline tasks */
+static void inline_sched(struct rxe_task *task)
+{
+	do_task(task);
 }
 
-void rxe_run_task(struct rxe_task *task)
+static void inline_run(struct rxe_task *task)
 {
-	if (task->destroyed)
-		return;
+	do_task(task);
+}
 
-	do_task(&task->tasklet);
+static void inline_disable(struct rxe_task *task)
+{
+	disable_task(task);
 }
 
-void rxe_sched_task(struct rxe_task *task)
+static void inline_enable(struct rxe_task *task)
 {
-	if (task->destroyed)
-		return;
+	enable_task(task);
+}
+
+static void inline_cleanup(struct rxe_task *task)
+{
+	cleanup_task(task);
+}
+
+static const struct rxe_task_ops inline_ops = {
+	.sched = inline_sched,
+	.run = inline_run,
+	.enable = inline_enable,
+	.disable = inline_disable,
+	.cleanup = inline_cleanup,
+};
 
+static void inline_init(struct rxe_task *task)
+{
+	task->ops = &inline_ops;
+}
+
+/* use tsklet_xxx to avoid name collisions with tasklet_xxx */
+static void tsklet_sched(struct rxe_task *task)
+{
 	tasklet_schedule(&task->tasklet);
 }
 
-void rxe_disable_task(struct rxe_task *task)
+static void tsklet_do_task(struct tasklet_struct *tasklet)
 {
+	struct rxe_task *task = container_of(tasklet, typeof(*task), tasklet);
+
+	do_task(task);
+}
+
+static void tsklet_run(struct rxe_task *task)
+{
+	do_task(task);
+}
+
+static void tsklet_disable(struct rxe_task *task)
+{
+	disable_task(task);
 	tasklet_disable(&task->tasklet);
 }
 
-void rxe_enable_task(struct rxe_task *task)
+static void tsklet_enable(struct rxe_task *task)
 {
 	tasklet_enable(&task->tasklet);
+	enable_task(task);
+}
+
+static void tsklet_cleanup(struct rxe_task *task)
+{
+	cleanup_task(task);
+	tasklet_kill(&task->tasklet);
+}
+
+static const struct rxe_task_ops tsklet_ops = {
+	.sched = tsklet_sched,
+	.run = tsklet_run,
+	.enable = tsklet_enable,
+	.disable = tsklet_disable,
+	.cleanup = tsklet_cleanup,
+};
+
+static void tsklet_init(struct rxe_task *task)
+{
+	tasklet_setup(&task->tasklet, tsklet_do_task);
+	task->ops = &tsklet_ops;
+}
+
+int rxe_init_task(struct rxe_task *task, void *arg, int (*func)(void *),
+		  enum rxe_task_type type)
+{
+	task->arg	= arg;
+	task->func	= func;
+	task->destroyed	= false;
+	task->type	= type;
+	task->state	= TASK_STATE_START;
+
+	spin_lock_init(&task->lock);
+
+	switch (type) {
+	case RXE_TASK_TYPE_INLINE:
+		inline_init(task);
+		break;
+	case RXE_TASK_TYPE_TASKLET:
+		tsklet_init(task);
+		break;
+	default:
+		pr_debug("%s: invalid task type = %d\n", __func__, type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+void rxe_sched_task(struct rxe_task *task)
+{
+	task->ops->sched(task);
+}
+
+void rxe_run_task(struct rxe_task *task)
+{
+	task->ops->run(task);
+}
+
+void rxe_enable_task(struct rxe_task *task)
+{
+	task->ops->enable(task);
+}
+
+void rxe_disable_task(struct rxe_task *task)
+{
+	task->ops->disable(task);
+}
+
+void rxe_cleanup_task(struct rxe_task *task)
+{
+	task->ops->cleanup(task);
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_task.h b/drivers/infiniband/sw/rxe/rxe_task.h
index 7b88129702ac..31963129ff7a 100644
--- a/drivers/infiniband/sw/rxe/rxe_task.h
+++ b/drivers/infiniband/sw/rxe/rxe_task.h
@@ -7,6 +7,21 @@
 #ifndef RXE_TASK_H
 #define RXE_TASK_H
 
+struct rxe_task;
+
+struct rxe_task_ops {
+	void (*sched)(struct rxe_task *task);
+	void (*run)(struct rxe_task *task);
+	void (*disable)(struct rxe_task *task);
+	void (*enable)(struct rxe_task *task);
+	void (*cleanup)(struct rxe_task *task);
+};
+
+enum rxe_task_type {
+	RXE_TASK_TYPE_INLINE	= 0,
+	RXE_TASK_TYPE_TASKLET	= 1,
+};
+
 enum {
 	TASK_STATE_START	= 0,
 	TASK_STATE_BUSY		= 1,
@@ -19,24 +34,19 @@ enum {
  * called again.
  */
 struct rxe_task {
-	struct tasklet_struct	tasklet;
-	int			state;
-	spinlock_t		lock;
-	void			*arg;
-	int			(*func)(void *arg);
-	int			ret;
-	bool			destroyed;
+	struct tasklet_struct		tasklet;
+	int				state;
+	spinlock_t			lock;
+	void				*arg;
+	int				(*func)(void *arg);
+	int				ret;
+	bool				destroyed;
+	const struct rxe_task_ops	*ops;
+	enum rxe_task_type		type;
 };
 
-/*
- * init rxe_task structure
- *	arg  => parameter to pass to fcn
- *	func => function to call until it returns != 0
- */
-int rxe_init_task(struct rxe_task *task, void *arg, int (*func)(void *));
-
-/* cleanup task */
-void rxe_cleanup_task(struct rxe_task *task);
+int rxe_init_task(struct rxe_task *task, void *arg, int (*func)(void *),
+		  enum rxe_task_type type);
 
 /*
  * raw call to func in loop without any checking
@@ -54,4 +64,6 @@ void rxe_disable_task(struct rxe_task *task);
 /* allow task to run */
 void rxe_enable_task(struct rxe_task *task);
 
+void rxe_cleanup_task(struct rxe_task *task);
+
 #endif /* RXE_TASK_H */
-- 
2.34.1