fbcon: fix locking harder

commit 054430e773c9a1e26f38e30156eff02dedfffc17 upstream.

Okay so Alan's patch handled the case where there was no registered fbcon,
however the other path entered in set_con2fb_map pit.

In there we called fbcon_takeover, but we also took the console lock in a couple
of places. So push the console lock out to the callers of set_con2fb_map,

this means fbmem and switcheroo needed to take the lock around the fb notifier
entry points that lead to this.

This should fix the efifb regression seen by Maarten.

Tested-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Tested-by: Lu Hua <huax.lu@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 58434e8..37fe246 100644 (file)
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -26,6 +26,7 @@
 #include <linux/fb.h>
 
 #include <linux/pci.h>
+#include <linux/console.h>
 #include <linux/vga_switcheroo.h>
 
 struct vga_switcheroo_client {
@@ -256,8 +257,10 @@ static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
 
        if (new_client->fb_info) {
                struct fb_event event;
+               console_lock();
                event.info = new_client->fb_info;
                fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
+               console_unlock();
        }
 
        ret = vgasr_priv.handler->switchto(new_client->id);

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 9b8bcab..7a36dff 100644 (file)
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -843,6 +843,8 @@ static void con2fb_init_display(struct vc_data *vc, struct fb_info *info,
  *
  *     Maps a virtual console @unit to a frame buffer device
  *     @newidx.
+ *
+ *     This should be called with the console lock held.
  */
 static int set_con2fb_map(int unit, int newidx, int user)
 {
@@ -860,7 +862,7 @@ static int set_con2fb_map(int unit, int newidx, int user)
 
        if (!search_for_mapped_con() || !con_is_bound(&fb_con)) {
                info_idx = newidx;
-               return fbcon_takeover(0);
+               return do_fbcon_takeover(0);
        }
 
        if (oldidx != -1)
@@ -868,7 +870,6 @@ static int set_con2fb_map(int unit, int newidx, int user)
 
        found = search_fb_in_map(newidx);
 
-       console_lock();
        con2fb_map[unit] = newidx;
        if (!err && !found)
                err = con2fb_acquire_newinfo(vc, info, unit, oldidx);
@@ -895,7 +896,6 @@ static int set_con2fb_map(int unit, int newidx, int user)
        if (!search_fb_in_map(info_idx))
                info_idx = newidx;
 
-       console_unlock();
        return err;
 }
 
@@ -3026,6 +3026,7 @@ static inline int fbcon_unbind(void)
 }
 #endif /* CONFIG_VT_HW_CONSOLE_BINDING */
 
+/* called with console_lock held */
 static int fbcon_fb_unbind(int idx)
 {
        int i, new_idx = -1, ret = 0;
@@ -3052,6 +3053,7 @@ static int fbcon_fb_unbind(int idx)
        return ret;
 }
 
+/* called with console_lock held */
 static int fbcon_fb_unregistered(struct fb_info *info)
 {
        int i, idx;
@@ -3089,6 +3091,7 @@ static int fbcon_fb_unregistered(struct fb_info *info)
        return 0;
 }
 
+/* called with console_lock held */
 static void fbcon_remap_all(int idx)
 {
        int i;
@@ -3133,6 +3136,7 @@ static inline void fbcon_select_primary(struct fb_info *info)
 }
 #endif /* CONFIG_FRAMEBUFFER_DETECT_PRIMARY */
 
+/* called with console_lock held */
 static int fbcon_fb_registered(struct fb_info *info)
 {
        int ret = 0, i, idx;
@@ -3285,6 +3289,7 @@ static int fbcon_event_notify(struct notifier_block *self,
                ret = fbcon_fb_unregistered(info);
                break;
        case FB_EVENT_SET_CONSOLE_MAP:
+               /* called with console lock held */
                con2fb = event->data;
                ret = set_con2fb_map(con2fb->console - 1,
                                     con2fb->framebuffer, 1);

diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index c133dde..babbb07 100644 (file)
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1154,8 +1154,10 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
                event.data = &con2fb;
                if (!lock_fb_info(info))
                        return -ENODEV;
+               console_lock();
                event.info = info;
                ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event);
+               console_unlock();
                unlock_fb_info(info);
                break;
        case FBIOBLANK: