rearange some code that handles the thread taskqueue so that it is more

generic.  Introduce a new define TASKQUEUE_DEFINE_THREAD that takes a
single arg, which is the name of the queue.

Document these changes.

share/man/man9/taskqueue.9

@@ -68,6 +68,7 @@ struct task {
 .Fn TASK_INIT "struct task *task" "int priority" "task_fn_t *func" "void *context"
 .Fn TASKQUEUE_DECLARE "name"
 .Fn TASKQUEUE_DEFINE "name" "taskqueue_enqueue_fn enqueue" "void *context" "init"
+.Fn TASKQUEUE_DEFINE_THREAD "name"
 .Sh DESCRIPTION
 These functions provide a simple interface for asynchronous execution
 of code.
@@ -159,12 +160,13 @@ are simply copied into the task structure fields and the
 .Va ta_pending
 field is cleared.
 .Pp
-Two macros
-.Fn TASKQUEUE_DECLARE "name"
+Three macros
+.Fn TASKQUEUE_DECLARE "name" ,
+.Fn TASKQUEUE_DEFINE "name" "enqueue" "context" "init" ,
 and
-.Fn TASKQUEUE_DEFINE "name" "enqueue" "context" "init"
-are used to declare a reference to a global queue
-and to define the implementation of the queue.
+.Fn TASKQUEUE_DEFINE_THREAD "name"
+are used to declare a reference to a global queue, to define the
+implementation of the queue, and declare a queue that uses it's own thread.
 The
 .Fn TASKQUEUE_DEFINE
 macro arranges to call
@@ -183,6 +185,16 @@ argument to the macro is executed as a C statement,
 allowing any further initialisation to be performed
 (such as registering an interrupt handler etc.)
 .Pp
+The
+.Fn TASKQUEUE_DEFINE_THREAD
+macro defines a new taskqueue with it's own kernel thread to serve tasks.  The
+variable
+.Vt struct proc *taskqueue_name_proc
+is defined which contains the kernel thread serving the tasks.
+The variable
+.Vt struct taskqueue *taskqueue_name
+is used to enqueue tasks onto the queue.
+.Pp
 The system provides three global taskqueues,
 .Va taskqueue_swi ,
 .Va taskqueue_swi_giant ,

sys/kern/subr_taskqueue.c

@@ -44,7 +44,6 @@ static void	*taskqueue_giant_ih;
 static void	*taskqueue_ih;
 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
 static struct mtx taskqueue_queues_mutex;
-static struct proc *taskqueue_thread_proc;
 
 struct taskqueue {
 	STAILQ_ENTRY(taskqueue)	tq_link;
@@ -226,24 +225,30 @@ taskqueue_swi_giant_run(void *dummy)
 	taskqueue_run(taskqueue_swi_giant);
 }
 
-static void
-taskqueue_thread_loop(void *dummy)
+void
+taskqueue_thread_loop(void *arg)
 {
+	struct taskqueue **tqp, *tq;
 
-	mtx_lock(&taskqueue_thread->tq_mutex);
+	tqp = arg;
+	tq = *tqp;
+	mtx_lock(&tq->tq_mutex);
 	for (;;) {
-		taskqueue_run(taskqueue_thread);
-		msleep(taskqueue_thread, &taskqueue_thread->tq_mutex, PWAIT,
-		    "-", 0); 
+		taskqueue_run(tq);
+		msleep(tq, &tq->tq_mutex, PWAIT, "-", 0); 
 	}
 }
 
-static void
+void
 taskqueue_thread_enqueue(void *context)
 {
+	struct taskqueue **tqp, *tq;
 
-	mtx_assert(&taskqueue_thread->tq_mutex, MA_OWNED);
-	wakeup(taskqueue_thread);
+	tqp = context;
+	tq = *tqp;
+
+	mtx_assert(&tq->tq_mutex, MA_OWNED);
+	wakeup(tq);
 }
 
 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
@@ -254,9 +259,7 @@ TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
 		 swi_add(NULL, "Giant task queue", taskqueue_swi_giant_run,
 		     NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 
 
-TASKQUEUE_DEFINE(thread, taskqueue_thread_enqueue, 0,
-		 kthread_create(taskqueue_thread_loop, NULL,
-		 &taskqueue_thread_proc, 0, 0, "taskqueue"));
+TASKQUEUE_DEFINE_THREAD(thread);
 
 int
 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)

sys/sys/taskqueue.h

@@ -55,6 +55,12 @@ struct taskqueue *taskqueue_find(const char *name);
 void	taskqueue_free(struct taskqueue *queue);
 void	taskqueue_run(struct taskqueue *queue);
 
+/*
+ * Functions for dedicated thread taskqueues
+ */
+void	taskqueue_thread_loop(void *arg);
+void	taskqueue_thread_enqueue(void *context);
+
 /*
  * Initialise a task structure.
  */
@@ -90,6 +96,11 @@ SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND,		\
 	taskqueue_define_##name, NULL)					\
 									\
 struct __hack
+#define TASKQUEUE_DEFINE_THREAD(name)					\
+static struct proc *taskqueue_##name##_proc;				\
+TASKQUEUE_DEFINE(name, taskqueue_thread_enqueue, &taskqueue_##name,	\
+	kthread_create(taskqueue_thread_loop, &taskqueue_##name,	\
+	&taskqueue_##name##_proc, 0, 0, #name " taskq"))
 
 /*
  * These queues are serviced by software interrupt handlers.  To enqueue