mini-os: use BSD sys/queue.h instead of Linux list.h

The latter is GPL which makes the whole of mini-os GPL rather than BSD
as intended. In tree users are all GPL or GPL-compatible but we should
fix this so that mini-os is BSD. Do so by using the same BSD
sys/queue.h as we use in libxl.

Tested with the builtin mini-os test app and qemu stubdomain, both of which
appear to still function as expected.

Move tools/libxl/external and the associated sed script to
tools/include/xen-external to allow more sensible access from mini-os.

Also add s/NULL/0/ in the sed script due to NULL not always being
defined in stubdom code when mini-os/wait.h is included.

As well as the obvious ABI changes there are a few API updates
associated with the change:

  - struct rw_semaphore.wait_list is unused
  - remove_waiter needs to take the wait_queue_head

The latter requires a qemu update, so there is also a QEMU_TAG
update in this changeset.

I sprinkled some extra-emacs local variables around the files I edited
which didn't have them.

I think this should be backported to the stable branches since
external users of mini-os may have been mislead into thinking they
could safely link mini-os against GPL-incompatible code.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

5 files changed, 50 insertions, 225 deletions

diff --git a/extras/mini-os/include/list.h b/extras/mini-os/include/list.h
deleted file mode 100644
index a60ae23431..0000000000
--- a/extras/mini-os/include/list.h
+++ /dev/null
@@ -1,190 +0,0 @@
-#ifndef _LINUX_LIST_H
-#define _LINUX_LIST_H
-
-/*
- * Simple doubly linked list implementation.
- *
- * Some of the internal functions ("__xxx") are useful when
- * manipulating whole lists rather than single entries, as
- * sometimes we already know the next/prev entries and we can
- * generate better code by using them directly rather than
- * using the generic single-entry routines.
- */
-
-struct minios_list_head {
-	struct minios_list_head *next, *prev;
-};
-
-#define MINIOS_LIST_HEAD_INIT(name) { &(name), &(name) }
-
-#define MINIOS_LIST_HEAD(name) \
-	struct minios_list_head name = MINIOS_LIST_HEAD_INIT(name)
-
-#define MINIOS_INIT_LIST_HEAD(ptr) do { \
-	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
-} while (0)
-
-#define minios_list_top(head, type, member)					  \
-({ 									  \
-	struct minios_list_head *_head = (head);				  \
-	minios_list_empty(_head) ? NULL : minios_list_entry(_head->next, type, member); \
-})
-
-/*
- * Insert a new entry between two known consecutive entries. 
- *
- * This is only for internal list manipulation where we know
- * the prev/next entries already!
- */
-static __inline__ void __minios_list_add(struct minios_list_head * new,
-	struct minios_list_head * prev,
-	struct minios_list_head * next)
-{
-	next->prev = new;
-	new->next = next;
-	new->prev = prev;
-	prev->next = new;
-}
-
-/**
- * minios_list_add - add a new entry
- * @new: new entry to be added
- * @head: list head to add it after
- *
- * Insert a new entry after the specified head.
- * This is good for implementing stacks.
- */
-static __inline__ void minios_list_add(struct minios_list_head *new, struct minios_list_head *head)
-{
-	__minios_list_add(new, head, head->next);
-}
-
-/**
- * minios_list_add_tail - add a new entry
- * @new: new entry to be added
- * @head: list head to add it before
- *
- * Insert a new entry before the specified head.
- * This is useful for implementing queues.
- */
-static __inline__ void minios_list_add_tail(struct minios_list_head *new, struct minios_list_head *head)
-{
-	__minios_list_add(new, head->prev, head);
-}
-
-/*
- * Delete a list entry by making the prev/next entries
- * point to each other.
- *
- * This is only for internal list manipulation where we know
- * the prev/next entries already!
- */
-static __inline__ void __minios_list_del(struct minios_list_head * prev,
-				  struct minios_list_head * next)
-{
-	next->prev = prev;
-	prev->next = next;
-}
-
-/**
- * minios_list_del - deletes entry from list.
- * @entry: the element to delete from the list.
- * Note: minios_list_empty on entry does not return true after this, the entry is in an undefined state.
- */
-static __inline__ void minios_list_del(struct minios_list_head *entry)
-{
-	__minios_list_del(entry->prev, entry->next);
-}
-
-/**
- * minios_list_del_init - deletes entry from list and reinitialize it.
- * @entry: the element to delete from the list.
- */
-static __inline__ void minios_list_del_init(struct minios_list_head *entry)
-{
-	__minios_list_del(entry->prev, entry->next);
-	MINIOS_INIT_LIST_HEAD(entry); 
-}
-
-/**
- * minios_list_empty - tests whether a list is empty
- * @head: the list to test.
- */
-static __inline__ int minios_list_empty(struct minios_list_head *head)
-{
-	return head->next == head;
-}
-
-/**
- * minios_list_splice - join two lists
- * @list: the new list to add.
- * @head: the place to add it in the first list.
- */
-static __inline__ void minios_list_splice(struct minios_list_head *list, struct minios_list_head *head)
-{
-	struct minios_list_head *first = list->next;
-
-	if (first != list) {
-		struct minios_list_head *last = list->prev;
-		struct minios_list_head *at = head->next;
-
-		first->prev = head;
-		head->next = first;
-
-		last->next = at;
-		at->prev = last;
-	}
-}
-
-/**
- * minios_list_entry - get the struct for this entry
- * @ptr:	the &struct minios_list_head pointer.
- * @type:	the type of the struct this is embedded in.
- * @member:	the name of the minios_list_struct within the struct.
- */
-#define minios_list_entry(ptr, type, member) \
-	((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
-
-/**
- * minios_list_for_each	-	iterate over a list
- * @pos:	the &struct minios_list_head to use as a loop counter.
- * @head:	the head for your list.
- */
-#define minios_list_for_each(pos, head) \
-	for (pos = (head)->next; pos != (head); pos = pos->next)
-        	
-/**
- * minios_list_for_each_safe	-	iterate over a list safe against removal of list entry
- * @pos:	the &struct minios_list_head to use as a loop counter.
- * @n:		another &struct minios_list_head to use as temporary storage
- * @head:	the head for your list.
- */
-#define minios_list_for_each_safe(pos, n, head) \
-	for (pos = (head)->next, n = pos->next; pos != (head); \
-		pos = n, n = pos->next)
-
-/**
- * minios_list_for_each_entry	-	iterate over list of given type
- * @pos:	the type * to use as a loop counter.
- * @head:	the head for your list.
- * @member:	the name of the minios_list_struct within the struct.
- */
-#define minios_list_for_each_entry(pos, head, member)				\
-	for (pos = minios_list_entry((head)->next, typeof(*pos), member);	\
-	     &pos->member != (head); 					\
-	     pos = minios_list_entry(pos->member.next, typeof(*pos), member))
-
-/**
- * minios_list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
- * @pos:	the type * to use as a loop counter.
- * @n:		another type * to use as temporary storage
- * @head:	the head for your list.
- * @member:	the name of the minios_list_struct within the struct.
- */
-#define minios_list_for_each_entry_safe(pos, n, head, member)			\
-	for (pos = minios_list_entry((head)->next, typeof(*pos), member),	\
-		n = minios_list_entry(pos->member.next, typeof(*pos), member);	\
-	     &pos->member != (head); 					\
-	     pos = n, n = minios_list_entry(n->member.next, typeof(*n), member))
-#endif /* _LINUX_LIST_H */
-
diff --git a/extras/mini-os/include/sched.h b/extras/mini-os/include/sched.h
index 538bed5b8d..ea3239d602 100644
--- a/extras/mini-os/include/sched.h
+++ b/extras/mini-os/include/sched.h
@@ -19,7 +19,7 @@ struct thread
 #else /* !defined(__ia64__) */
     thread_regs_t regs;
 #endif /* !defined(__ia64__) */
-    struct minios_list_head thread_list;
+    MINIOS_TAILQ_ENTRY(struct thread) thread_list;
     uint32_t flags;
     s_time_t wakeup_time;
 #ifdef HAVE_LIBC
diff --git a/extras/mini-os/include/semaphore.h b/extras/mini-os/include/semaphore.h
index 8236046714..47470c511a 100644
--- a/extras/mini-os/include/semaphore.h
+++ b/extras/mini-os/include/semaphore.h
@@ -21,7 +21,6 @@ struct semaphore
 struct rw_semaphore {
 	signed long		count;
 	spinlock_t		wait_lock;
-	struct minios_list_head	wait_list;
 	int			debug;
 };
 
diff --git a/extras/mini-os/include/wait.h b/extras/mini-os/include/wait.h
index 10b9f29b07..bffa3c444c 100644
--- a/extras/mini-os/include/wait.h
+++ b/extras/mini-os/include/wait.h
@@ -5,47 +5,47 @@
 #include <mini-os/os.h>
 #include <mini-os/waittypes.h>
 
-#define DEFINE_WAIT(name)                               \
-struct wait_queue name = {                              \
-    .thread       = get_current(),                            \
-    .thread_list  = MINIOS_LIST_HEAD_INIT((name).thread_list), \
+#define DEFINE_WAIT(name)                          \
+struct wait_queue name = {                         \
+    .thread       = get_current(),                 \
+    .waiting      = 0,                             \
 }
 
 
 static inline void init_waitqueue_head(struct wait_queue_head *h)
 {
-  MINIOS_INIT_LIST_HEAD(&h->thread_list);
+    MINIOS_STAILQ_INIT(h);
 }
 
 static inline void init_waitqueue_entry(struct wait_queue *q, struct thread *thread)
 {
     q->thread = thread;
-    MINIOS_INIT_LIST_HEAD(&q->thread_list);
+    q->waiting = 0;
 }
 
-
 static inline void add_wait_queue(struct wait_queue_head *h, struct wait_queue *q)
 {
-    if (minios_list_empty(&q->thread_list))
-        minios_list_add(&q->thread_list, &h->thread_list);   
+    if (!q->waiting) {
+        MINIOS_STAILQ_INSERT_HEAD(h, q, thread_list);
+        q->waiting = 1;
+    }
 }
 
-static inline void remove_wait_queue(struct wait_queue *q)
+static inline void remove_wait_queue(struct wait_queue_head *h, struct wait_queue *q)
 {
-    minios_list_del(&q->thread_list);
+    if (q->waiting) {
+        MINIOS_STAILQ_REMOVE(h, q, struct wait_queue, thread_list);
+        q->waiting = 0;
+    }
 }
 
 static inline void wake_up(struct wait_queue_head *head)
 {
     unsigned long flags;
-    struct minios_list_head *tmp, *next;
+    struct wait_queue *curr, *tmp;
     local_irq_save(flags);
-    minios_list_for_each_safe(tmp, next, &head->thread_list)
-    {
-         struct wait_queue *curr;
-         curr = minios_list_entry(tmp, struct wait_queue, thread_list);
+    MINIOS_STAILQ_FOREACH_SAFE(curr, head, thread_list, tmp)
          wake(curr->thread);
-    }
     local_irq_restore(flags);
 }
 
@@ -57,11 +57,11 @@ static inline void wake_up(struct wait_queue_head *head)
     local_irq_restore(flags);   \
 } while (0)
 
-#define remove_waiter(w) do {   \
-    unsigned long flags;        \
-    local_irq_save(flags);      \
-    remove_wait_queue(&w);      \
-    local_irq_restore(flags);   \
+#define remove_waiter(w, wq) do {  \
+    unsigned long flags;           \
+    local_irq_save(flags);         \
+    remove_wait_queue(&wq, &w);    \
+    local_irq_restore(flags);      \
 } while (0)
 
 #define wait_event_deadline(wq, condition, deadline) do {       \
@@ -84,7 +84,7 @@ static inline void wake_up(struct wait_queue_head *head)
     local_irq_save(flags);                                      \
     /* need to wake up */                                       \
     wake(get_current());                                        \
-    remove_wait_queue(&__wait);                                 \
+    remove_wait_queue(&wq, &__wait);                            \
     local_irq_restore(flags);                                   \
 } while(0) 
 
@@ -93,3 +93,13 @@ static inline void wake_up(struct wait_queue_head *head)
 
 
 #endif /* __WAIT_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/extras/mini-os/include/waittypes.h b/extras/mini-os/include/waittypes.h
index 1215ffe0be..78d91c1542 100644
--- a/extras/mini-os/include/waittypes.h
+++ b/extras/mini-os/include/waittypes.h
@@ -6,21 +6,27 @@
 struct thread;
 struct wait_queue
 {
+    int waiting;
     struct thread *thread;
-    struct minios_list_head thread_list;
+    MINIOS_STAILQ_ENTRY(struct wait_queue) thread_list;
 };
 
-struct wait_queue_head
-{
-    /* TODO - lock required? */
-    struct minios_list_head thread_list;
-};
+/* TODO - lock required? */
+MINIOS_STAILQ_HEAD(wait_queue_head, struct wait_queue);
 
 #define DECLARE_WAIT_QUEUE_HEAD(name) \
-   struct wait_queue_head name =     \
-        { .thread_list = { &(name).thread_list, &(name).thread_list} }
+    struct wait_queue_head name = MINIOS_STAILQ_HEAD_INITIALIZER(name)
 
-#define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
-    .thread_list      = { &(name).thread_list, &(name).thread_list } }
+#define __WAIT_QUEUE_HEAD_INITIALIZER(name) MINIOS_STAILQ_HEAD_INITIALIZER(name)
 
 #endif
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */