3 files changed, 67 insertions, 71 deletions

diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 5316e8a4a4f..c73dfa78f94 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -329,6 +329,7 @@ extern void os_set_ioignore(void);
 extern void init_irq_signals(int on_sigstack);
 
 /* sigio.c */
+extern int add_sigio_fd(int fd);
 extern int ignore_sigio_fd(int fd);
 extern void maybe_sigio_broken(int fd, int read);
 
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 589c69a7504..ce7f233fc49 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -142,19 +142,6 @@ int activate_fd(int irq, int fd, int type, void *dev_id)
 				     .events 		= events,
 				     .current_events 	= 0 } );
 
-	/* Critical section - locked by a spinlock because this stuff can
-	 * be changed from interrupt handlers.  The stuff above is done
-	 * outside the lock because it allocates memory.
-	 */
-
-	/* Actually, it only looks like it can be called from interrupt
-	 * context.  The culprit is reactivate_fd, which calls
-	 * maybe_sigio_broken, which calls write_sigio_workaround,
-	 * which calls activate_fd.  However, write_sigio_workaround should
-	 * only be called once, at boot time.  That would make it clear that
-	 * this is called only from process context, and can be locked with
-	 * a semaphore.
-	 */
 	spin_lock_irqsave(&irq_lock, flags);
 	for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 		if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
@@ -165,7 +152,6 @@ int activate_fd(int irq, int fd, int type, void *dev_id)
 		}
 	}
 
-	/*-------------*/
 	if (type == IRQ_WRITE)
 		fd = -1;
 
@@ -198,7 +184,6 @@ int activate_fd(int irq, int fd, int type, void *dev_id)
 
 		spin_lock_irqsave(&irq_lock, flags);
 	}
-	/*-------------*/
 
 	*last_irq_ptr = new_fd;
 	last_irq_ptr = &new_fd->next;
@@ -210,14 +195,14 @@ int activate_fd(int irq, int fd, int type, void *dev_id)
 	 */
 	maybe_sigio_broken(fd, (type == IRQ_READ));
 
-	return(0);
+	return 0;
 
  out_unlock:
 	spin_unlock_irqrestore(&irq_lock, flags);
  out_kfree:
 	kfree(new_fd);
  out:
-	return(err);
+	return err;
 }
 
 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
@@ -302,10 +287,7 @@ void reactivate_fd(int fd, int irqnum)
 	os_set_pollfd(i, irq->fd);
 	spin_unlock_irqrestore(&irq_lock, flags);
 
-	/* This calls activate_fd, so it has to be outside the critical
-	 * section.
-	 */
-	maybe_sigio_broken(fd, (irq->type == IRQ_READ));
+	add_sigio_fd(fd);
 }
 
 void deactivate_fd(int fd, int irqnum)
@@ -316,11 +298,15 @@ void deactivate_fd(int fd, int irqnum)
 
 	spin_lock_irqsave(&irq_lock, flags);
 	irq = find_irq_by_fd(fd, irqnum, &i);
-	if (irq == NULL)
-		goto out;
+	if(irq == NULL){
+		spin_unlock_irqrestore(&irq_lock, flags);
+		return;
+	}
+
 	os_set_pollfd(i, -1);
- out:
 	spin_unlock_irqrestore(&irq_lock, flags);
+
+	ignore_sigio_fd(fd);
 }
 
 int deactivate_all_fds(void)
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 0ecac563c7b..f6457765b17 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -43,17 +43,9 @@ struct pollfds {
 /* Protected by sigio_lock().  Used by the sigio thread, but the UML thread
  * synchronizes with it.
  */
-static struct pollfds current_poll = {
-	.poll  		= NULL,
-	.size 		= 0,
-	.used 		= 0
-};
-
-static struct pollfds next_poll = {
-	.poll  		= NULL,
-	.size 		= 0,
-	.used 		= 0
-};
+static struct pollfds current_poll;
+static struct pollfds next_poll;
+static struct pollfds all_sigio_fds;
 
 static int write_sigio_thread(void *unused)
 {
@@ -78,7 +70,8 @@ static int write_sigio_thread(void *unused)
 				n = os_read_file(sigio_private[1], &c, sizeof(c));
 				if(n != sizeof(c))
 					printk("write_sigio_thread : "
-					       "read failed, err = %d\n", -n);
+					       "read on socket failed, "
+					       "err = %d\n", -n);
 				tmp = current_poll;
 				current_poll = next_poll;
 				next_poll = tmp;
@@ -93,35 +86,36 @@ static int write_sigio_thread(void *unused)
 
 			n = os_write_file(respond_fd, &c, sizeof(c));
 			if(n != sizeof(c))
-				printk("write_sigio_thread : write failed, "
-				       "err = %d\n", -n);
+				printk("write_sigio_thread : write on socket "
+				       "failed, err = %d\n", -n);
 		}
 	}
 
 	return 0;
 }
 
-static int need_poll(int n)
+static int need_poll(struct pollfds *polls, int n)
 {
-	if(n <= next_poll.size){
-		next_poll.used = n;
-		return(0);
+	if(n <= polls->size){
+		polls->used = n;
+		return 0;
 	}
-	kfree(next_poll.poll);
-	next_poll.poll = um_kmalloc_atomic(n * sizeof(struct pollfd));
-	if(next_poll.poll == NULL){
+	kfree(polls->poll);
+	polls->poll = um_kmalloc_atomic(n * sizeof(struct pollfd));
+	if(polls->poll == NULL){
 		printk("need_poll : failed to allocate new pollfds\n");
-		next_poll.size = 0;
-		next_poll.used = 0;
-		return(-1);
+		polls->size = 0;
+		polls->used = 0;
+		return -ENOMEM;
 	}
-	next_poll.size = n;
-	next_poll.used = n;
-	return(0);
+	polls->size = n;
+	polls->used = n;
+	return 0;
 }
 
 /* Must be called with sigio_lock held, because it's needed by the marked
- * critical section. */
+ * critical section.
+ */
 static void update_thread(void)
 {
 	unsigned long flags;
@@ -156,34 +150,39 @@ static void update_thread(void)
 	set_signals(flags);
 }
 
-static int add_sigio_fd(int fd, int read)
+int add_sigio_fd(int fd)
 {
-	int err = 0, i, n, events;
+	struct pollfd *p;
+	int err = 0, i, n;
 
 	sigio_lock();
+	for(i = 0; i < all_sigio_fds.used; i++){
+		if(all_sigio_fds.poll[i].fd == fd)
+			break;
+	}
+	if(i == all_sigio_fds.used)
+		goto out;
+
+	p = &all_sigio_fds.poll[i];
+
 	for(i = 0; i < current_poll.used; i++){
 		if(current_poll.poll[i].fd == fd)
 			goto out;
 	}
 
 	n = current_poll.used + 1;
-	err = need_poll(n);
+	err = need_poll(&next_poll, n);
 	if(err)
 		goto out;
 
 	for(i = 0; i < current_poll.used; i++)
 		next_poll.poll[i] = current_poll.poll[i];
 
-	if(read) events = POLLIN;
-	else events = POLLOUT;
-
-	next_poll.poll[n - 1] = ((struct pollfd) { .fd  	= fd,
-						   .events 	= events,
-						   .revents 	= 0 });
+	next_poll.poll[n - 1] = *p;
 	update_thread();
  out:
 	sigio_unlock();
-	return(err);
+	return err;
 }
 
 int ignore_sigio_fd(int fd)
@@ -205,18 +204,14 @@ int ignore_sigio_fd(int fd)
 	if(i == current_poll.used)
 		goto out;
 
-	err = need_poll(current_poll.used - 1);
+	err = need_poll(&next_poll, current_poll.used - 1);
 	if(err)
 		goto out;
 
 	for(i = 0; i < current_poll.used; i++){
 		p = &current_poll.poll[i];
-		if(p->fd != fd) next_poll.poll[n++] = current_poll.poll[i];
-	}
-	if(n == i){
-		printk("ignore_sigio_fd : fd %d not found\n", fd);
-		err = -1;
-		goto out;
+		if(p->fd != fd)
+			next_poll.poll[n++] = *p;
 	}
 
 	update_thread();
@@ -234,7 +229,7 @@ static struct pollfd *setup_initial_poll(int fd)
 		printk("setup_initial_poll : failed to allocate poll\n");
 		return NULL;
 	}
-	*p = ((struct pollfd) { .fd  	= fd,
+	*p = ((struct pollfd) { .fd		= fd,
 				.events 	= POLLIN,
 				.revents 	= 0 });
 	return p;
@@ -323,6 +318,8 @@ out_close1:
 
 void maybe_sigio_broken(int fd, int read)
 {
+	int err;
+
 	if(!isatty(fd))
 		return;
 
@@ -330,7 +327,19 @@ void maybe_sigio_broken(int fd, int read)
 		return;
 
 	write_sigio_workaround();
-	add_sigio_fd(fd, read);
+
+	sigio_lock();
+	err = need_poll(&all_sigio_fds, all_sigio_fds.used + 1);
+	if(err){
+		printk("maybe_sigio_broken - failed to add pollfd\n");
+		goto out;
+	}
+	all_sigio_fds.poll[all_sigio_fds.used++] =
+		((struct pollfd) { .fd  	= fd,
+				   .events 	= read ? POLLIN : POLLOUT,
+				   .revents 	= 0 });
+out:
+	sigio_unlock();
 }
 
 static void sigio_cleanup(void)