vgacon: Fix & cleanup refcounting

The vgacon driver prepares a two element array of uni_pagedir_loc and
uses the second item as its own reference counter for sharing the
uni_pagedir.  And the code assumes blindly that the second item is
available if the assigned vc_uni_pagedir isn't the standard one, which
might be wrong (although currently it's so).

This patch fixes that wrong assumption, and gives a slight cleanup
along with it: namely, instead of array, just give the uni_pagedir_loc
and a separate refcount variable.  It makes the code a bit more
understandable at first glance.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 7 deletions

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 9d8feac67637..9e18770aaba6 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -87,7 +87,8 @@ static void vgacon_save_screen(struct vc_data *c);
 static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,
                          int lines);
 static void vgacon_invert_region(struct vc_data *c, u16 * p, int count);
-static unsigned long vgacon_uni_pagedir[2];
+static unsigned long vgacon_uni_pagedir;
+static int vgacon_refcount;
 
 /* Description of the hardware situation */
 static int              vga_init_done           __read_mostly;
@@ -575,12 +576,12 @@ static void vgacon_init(struct vc_data *c, int init)
         if (vga_512_chars)
                 c->vc_hi_font_mask = 0x0800;
         p = *c->vc_uni_pagedir_loc;
-        if (c->vc_uni_pagedir_loc == &c->vc_uni_pagedir ||
-            !--c->vc_uni_pagedir_loc[1])
+        if (c->vc_uni_pagedir_loc != &vgacon_uni_pagedir) {
                 con_free_unimap(c);
-        c->vc_uni_pagedir_loc = vgacon_uni_pagedir;
-        vgacon_uni_pagedir[1]++;
-        if (!vgacon_uni_pagedir[0] && p)
+                c->vc_uni_pagedir_loc = &vgacon_uni_pagedir;
+                vgacon_refcount++;
+        }
+        if (!vgacon_uni_pagedir && p)
                 con_set_default_unimap(c);
 
         /* Only set the default if the user didn't deliberately override it */
@@ -597,7 +598,7 @@ static void vgacon_deinit(struct vc_data *c)
                 vga_set_mem_top(c);
         }
 
-        if (!--vgacon_uni_pagedir[1])
+        if (!--vgacon_refcount)
                 con_free_unimap(c);
         c->vc_uni_pagedir_loc = &c->vc_uni_pagedir;
         con_set_default_unimap(c);