Merge branch 'fbmem'

* fbmem:
  Further fbcon sanity checking
  fbmem: fix remove_conflicting_framebuffers races

1 files changed, 71 insertions, 52 deletions

diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index ea16e654a9b..5aac00eb183 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1537,8 +1537,10 @@ static bool fb_do_apertures_overlap(struct apertures_struct *gena,
         return false;
 }
 
+static int do_unregister_framebuffer(struct fb_info *fb_info);
+
 #define VGA_FB_PHYS 0xA0000
-void remove_conflicting_framebuffers(struct apertures_struct *a,
+static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
                                      const char *name, bool primary)
 {
         int i;
@@ -1560,39 +1562,26 @@ void remove_conflicting_framebuffers(struct apertures_struct *a,
                         printk(KERN_INFO "fb: conflicting fb hw usage "
                                "%s vs %s - removing generic driver\n",
                                name, registered_fb[i]->fix.id);
-                        unregister_framebuffer(registered_fb[i]);
+                        do_unregister_framebuffer(registered_fb[i]);
                 }
         }
 }
-EXPORT_SYMBOL(remove_conflicting_framebuffers);
-
-/**
- *      register_framebuffer - registers a frame buffer device
- *      @fb_info: frame buffer info structure
- *
- *      Registers a frame buffer device @fb_info.
- *
- *      Returns negative errno on error, or zero for success.
- *
- */
 
-int
-register_framebuffer(struct fb_info *fb_info)
+static int do_register_framebuffer(struct fb_info *fb_info)
 {
         int i;
         struct fb_event event;
         struct fb_videomode mode;
 
-        if (num_registered_fb == FB_MAX)
-                return -ENXIO;
-
         if (fb_check_foreignness(fb_info))
                 return -ENOSYS;
 
-        remove_conflicting_framebuffers(fb_info->apertures, fb_info->fix.id,
+        do_remove_conflicting_framebuffers(fb_info->apertures, fb_info->fix.id,
                                          fb_is_primary_device(fb_info));
 
-        mutex_lock(&registration_lock);
+        if (num_registered_fb == FB_MAX)
+                return -ENXIO;
+
         num_registered_fb++;
         for (i = 0 ; i < FB_MAX; i++)
                 if (!registered_fb[i])
@@ -1635,7 +1624,6 @@ register_framebuffer(struct fb_info *fb_info)
         fb_var_to_videomode(&mode, &fb_info->var);
         fb_add_videomode(&mode, &fb_info->modelist);
         registered_fb[i] = fb_info;
-        mutex_unlock(&registration_lock);
 
         event.info = fb_info;
         if (!lock_fb_info(fb_info))
@@ -1645,37 +1633,14 @@ register_framebuffer(struct fb_info *fb_info)
         return 0;
 }
 
-
-/**
- *      unregister_framebuffer - releases a frame buffer device
- *      @fb_info: frame buffer info structure
- *
- *      Unregisters a frame buffer device @fb_info.
- *
- *      Returns negative errno on error, or zero for success.
- *
- *      This function will also notify the framebuffer console
- *      to release the driver.
- *
- *      This is meant to be called within a driver's module_exit()
- *      function. If this is called outside module_exit(), ensure
- *      that the driver implements fb_open() and fb_release() to
- *      check that no processes are using the device.
- */
-
-int
-unregister_framebuffer(struct fb_info *fb_info)
+static int do_unregister_framebuffer(struct fb_info *fb_info)
 {
         struct fb_event event;
         int i, ret = 0;
 
-        mutex_lock(&registration_lock);
         i = fb_info->node;
-        if (!registered_fb[i]) {
-                ret = -EINVAL;
-                goto done;
-        }
-
+        if (i < 0 || i >= FB_MAX || registered_fb[i] != fb_info)
+                return -EINVAL;
 
         if (!lock_fb_info(fb_info))
                 return -ENODEV;
@@ -1683,10 +1648,8 @@ unregister_framebuffer(struct fb_info *fb_info)
         ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event);
         unlock_fb_info(fb_info);
 
-        if (ret) {
-                ret = -EINVAL;
-                goto done;
-        }
+        if (ret)
+                return -EINVAL;
 
         if (fb_info->pixmap.addr &&
             (fb_info->pixmap.flags & FB_PIXMAP_DEFAULT))
@@ -1701,8 +1664,64 @@ unregister_framebuffer(struct fb_info *fb_info)
 
         /* this may free fb info */
         put_fb_info(fb_info);
-done:
+        return 0;
+}
+
+void remove_conflicting_framebuffers(struct apertures_struct *a,
+                                     const char *name, bool primary)
+{
+        mutex_lock(&registration_lock);
+        do_remove_conflicting_framebuffers(a, name, primary);
+        mutex_unlock(&registration_lock);
+}
+EXPORT_SYMBOL(remove_conflicting_framebuffers);
+
+/**
+ *      register_framebuffer - registers a frame buffer device
+ *      @fb_info: frame buffer info structure
+ *
+ *      Registers a frame buffer device @fb_info.
+ *
+ *      Returns negative errno on error, or zero for success.
+ *
+ */
+int
+register_framebuffer(struct fb_info *fb_info)
+{
+        int ret;
+
+        mutex_lock(&registration_lock);
+        ret = do_register_framebuffer(fb_info);
+        mutex_unlock(&registration_lock);
+
+        return ret;
+}
+
+/**
+ *      unregister_framebuffer - releases a frame buffer device
+ *      @fb_info: frame buffer info structure
+ *
+ *      Unregisters a frame buffer device @fb_info.
+ *
+ *      Returns negative errno on error, or zero for success.
+ *
+ *      This function will also notify the framebuffer console
+ *      to release the driver.
+ *
+ *      This is meant to be called within a driver's module_exit()
+ *      function. If this is called outside module_exit(), ensure
+ *      that the driver implements fb_open() and fb_release() to
+ *      check that no processes are using the device.
+ */
+int
+unregister_framebuffer(struct fb_info *fb_info)
+{
+        int ret;
+
+        mutex_lock(&registration_lock);
+        ret = do_unregister_framebuffer(fb_info);
         mutex_unlock(&registration_lock);
+
         return ret;
 }