3 files changed, 67 insertions, 71 deletions

diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 5316e8a4a4fd..c73dfa78f943 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 589c69a75043..ce7f233fc490 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 0ecac563c7b3..f6457765b17d 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)