[src/trunk]: src/sys/external/bsd/common Add mega-kludgerific current_work().

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/442de026706e
branches:  trunk
changeset: 365854:442de026706e
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Mon Aug 27 07:00:28 2018 +0000

description:
Add mega-kludgerific current_work().

diffstat:

 sys/external/bsd/common/include/linux/workqueue.h |    6 +-
 sys/external/bsd/common/linux/linux_work.c        |  127 +++++++++++++++++++++-
 2 files changed, 128 insertions(+), 5 deletions(-)

diffs (206 lines):

diff -r 8e543fa902f2 -r 442de026706e sys/external/bsd/common/include/linux/workqueue.h
--- a/sys/external/bsd/common/include/linux/workqueue.h Mon Aug 27 07:00:09 2018 +0000
+++ b/sys/external/bsd/common/include/linux/workqueue.h Mon Aug 27 07:00:28 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: workqueue.h,v 1.3 2018/08/27 06:55:23 riastradh Exp $  */
+/*     $NetBSD: workqueue.h,v 1.4 2018/08/27 07:00:28 riastradh Exp $  */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -46,6 +46,7 @@
 #define        cancel_delayed_work_sync        linux_cancel_delayed_work_sync
 #define        cancel_work                     linux_cancel_work
 #define        cancel_work_sync                linux_cancel_work_sync
+#define        current_work                    linux_current_work
 #define        destroy_workqueue               linux_destroy_workqueue
 #define        flush_work                      linux_flush_work
 #define        flush_workqueue                 linux_flush_workqueue
@@ -118,6 +119,9 @@
 bool   cancel_delayed_work(struct delayed_work *);
 bool   cancel_delayed_work_sync(struct delayed_work *);
 
+struct work_struct *
+       current_work(void);
+
 #define        INIT_WORK_ONSTACK               INIT_WORK
 
 static inline void
diff -r 8e543fa902f2 -r 442de026706e sys/external/bsd/common/linux/linux_work.c
--- a/sys/external/bsd/common/linux/linux_work.c        Mon Aug 27 07:00:09 2018 +0000
+++ b/sys/external/bsd/common/linux/linux_work.c        Mon Aug 27 07:00:28 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_work.c,v 1.2 2018/08/27 06:55:23 riastradh Exp $ */
+/*     $NetBSD: linux_work.c,v 1.3 2018/08/27 07:00:28 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_work.c,v 1.2 2018/08/27 06:55:23 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_work.c,v 1.3 2018/08/27 07:00:28 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -60,6 +60,9 @@
 struct workqueue_struct {
        struct workqueue                *wq_workqueue;
 
+       struct rb_node                  wq_node;
+       struct lwp                      *wq_lwp;
+
        /* XXX The following should all be per-CPU.  */
        kmutex_t                        wq_lock;
 
@@ -92,10 +95,19 @@
 struct workqueue_struct                *system_wq;
 struct workqueue_struct                *system_long_wq;
 
+static struct {
+       kmutex_t                lock;
+       struct rb_tree          tree;
+} workqueues __cacheline_aligned;
+
+static const rb_tree_ops_t     workqueues_rb_ops;
+
 int
 linux_workqueue_init(void)
 {
-       int error;
+
+       mutex_init(&workqueues.lock, MUTEX_DEFAULT, IPL_VM);
+       rb_tree_init(&workqueues.tree, &workqueues_rb_ops);
 
        system_wq = alloc_ordered_workqueue("lnxsyswq", 0);
        if (system_wq == NULL)
@@ -110,7 +122,8 @@
 fail2: __unused
        destroy_workqueue(system_long_wq);
 fail1: destroy_workqueue(system_wq);
-fail0: return ENOMEM;
+fail0: mutex_destroy(&workqueues.lock);
+       return ENOMEM;
 }
 
 void
@@ -121,6 +134,109 @@
        system_long_wq = NULL;
        destroy_workqueue(system_wq);
        system_wq = NULL;
+       KASSERT(RB_TREE_MIN(&workqueues.tree) == NULL);
+       mutex_destroy(&workqueues.lock);
+}
+
+/*
+ * Table of workqueue LWPs for validation -- assumes there is only one
+ * thread per workqueue.
+ *
+ * XXX Mega-kludgerific!
+ */
+
+static int
+compare_nodes(void *cookie, const void *va, const void *vb)
+{
+       const struct workqueue_struct *wa = va;
+       const struct workqueue_struct *wb = vb;
+
+       if ((uintptr_t)wa->wq_lwp < (uintptr_t)wb->wq_lwp)
+               return -1;
+       if ((uintptr_t)wa->wq_lwp > (uintptr_t)wb->wq_lwp)
+               return +1;
+       return 0;
+}
+
+static int
+compare_key(void *cookie, const void *vn, const void *vk)
+{
+       const struct workqueue_struct *w = vn;
+       const struct lwp *lwp = vk;
+
+       if ((uintptr_t)w->wq_lwp < (uintptr_t)lwp)
+               return -1;
+       if ((uintptr_t)w->wq_lwp > (uintptr_t)lwp)
+               return +1;
+       return 0;
+}
+
+static const rb_tree_ops_t workqueues_rb_ops = {
+       .rbto_compare_nodes = compare_nodes,
+       .rbto_compare_key = compare_key,
+       .rbto_node_offset = offsetof(struct workqueue_struct, wq_lwp),
+};
+
+struct wq_whoami_work {
+       kmutex_t                www_lock;
+       kcondvar_t              www_cv;
+       struct workqueue_struct *www_wq;
+       struct work_struct      www_work;
+};
+
+static void
+workqueue_whoami_work(struct work_struct *work)
+{
+       struct wq_whoami_work *www = www;
+       struct workqueue_struct *wq = www->www_wq;
+
+       KASSERT(wq->wq_lwp == NULL);
+       wq->wq_lwp = curlwp;
+
+       mutex_enter(&www->www_lock);
+       cv_broadcast(&www->www_cv);
+       mutex_exit(&www->www_lock);
+}
+
+static void
+workqueue_whoami(struct workqueue_struct *wq)
+{
+       struct wq_whoami_work www;
+       struct workqueue_struct *collision __diagused;
+
+       mutex_init(&www.www_lock, MUTEX_DEFAULT, IPL_NONE);
+       cv_init(&www.www_cv, "wqwhoami");
+
+       INIT_WORK(&www.www_work, &workqueue_whoami_work);
+       queue_work(wq, &www.www_work);
+
+       mutex_enter(&www.www_lock);
+       while (wq->wq_lwp == NULL)
+               cv_wait(&www.www_cv, &www.www_lock);
+       mutex_exit(&www.www_lock);
+
+       cv_destroy(&www.www_cv);
+       mutex_destroy(&www.www_lock);
+
+       mutex_enter(&workqueues.lock);
+       collision = rb_tree_insert_node(&workqueues.tree, wq);
+       mutex_exit(&workqueues.lock);
+
+       KASSERT(collision == wq);
+}
+
+struct work_struct *
+current_work(void)
+{
+       struct workqueue_struct *wq;
+       struct work_struct *work;
+
+       mutex_enter(&workqueues.lock);
+       wq = rb_tree_find_node(&workqueues.tree, curlwp);
+       work = (wq == NULL ? NULL : wq->wq_current_work);
+       mutex_exit(&workqueues.lock);
+
+       return work;
 }
 
 /*
@@ -149,6 +265,9 @@
        TAILQ_INIT(&wq->wq_delayed);
        wq->wq_current_work = NULL;
 
+       workqueue_whoami(wq);
+       KASSERT(wq->wq_lwp != NULL);
+
        return wq;
 }