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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>
This commit is contained in:
Takashi Iwai 2014-05-13 12:09:27 +02:00 committed by Greg Kroah-Hartman
parent 4061f4987b
commit 0f2893f0d1
1 changed files with 8 additions and 7 deletions
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15
drivers/video/console/vgacon.c
View File

@ -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);