[PATCH 67/72] fbcon: fix locking harder

From: Luis Henriques
Date: Thu Apr 18 2013 - 05:20:20 EST


3.5.7.11 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Dave Airlie <airlied@xxxxxxxxx>

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@xxxxxxxxxxxxx>
Tested-by: Lu Hua <huax.lu@xxxxxxxxx>
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/gpu/vga/vga_switcheroo.c | 3 +++
drivers/video/console/fbcon.c | 11 ++++++++---
drivers/video/fbmem.c | 2 ++
3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 5b3c7d1..4d53351 100644
--- 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>

#include <linux/vgaarb.h>
@@ -323,8 +324,10 @@ 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 5bf163e..18ded2d 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -842,6 +842,8 @@ 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)
{
@@ -859,7 +861,7 @@ 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)
@@ -867,7 +869,6 @@ 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);
@@ -894,7 +895,6 @@ 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;
}

@@ -3025,6 +3025,7 @@ 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;
@@ -3051,6 +3052,7 @@ 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;
@@ -3088,6 +3090,7 @@ 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;
@@ -3132,6 +3135,7 @@ 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;
@@ -3284,6 +3288,7 @@ 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 afa804f..e4cc585 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1177,8 +1177,10 @@ 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:
--
1.8.1.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/