Re: [PATCH 1/2] Video: fb, add true ref_count atomicity
Jiri Slaby wrote: video/fb, add true ref_count atomicity Some of fb drivers uses atomic_t in bad manner, since there are still some race-prone gaps. Use mutexes to protect open/close code sections with ref_count testing and finally use simple uint. Signed-off-by: Jiri Slaby <[EMAIL PROTECTED]> Acked-by: Denis Oliver Kropp <[EMAIL PROTECTED]> -- Best regards, Denis Oliver Kropp .--. | DirectFB - Hardware accelerated graphics | | http://www.directfb.org/ | '--' - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/2] Video: fb, add true ref_count atomicity
Jiri Slaby wrote: video/fb, add true ref_count atomicity Some of fb drivers uses atomic_t in bad manner, since there are still some race-prone gaps. Use mutexes to protect open/close code sections with ref_count testing and finally use simple uint. Signed-off-by: Jiri Slaby [EMAIL PROTECTED] Acked-by: Denis Oliver Kropp [EMAIL PROTECTED] -- Best regards, Denis Oliver Kropp .--. | DirectFB - Hardware accelerated graphics | | http://www.directfb.org/ | '--' - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/2] Video: fb, add true ref_count atomicity
video/fb, add true ref_count atomicity
Some of fb drivers uses atomic_t in bad manner, since there are still some
race-prone gaps. Use mutexes to protect open/close code sections with
ref_count testing and finally use simple uint.
Signed-off-by: Jiri Slaby <[EMAIL PROTECTED]>
---
commit fd6de4a65b2d83db766a9ad3c137c44e361d6e0d
tree a4573d343d20988b931313c5fa35d9c370f36a05
parent e8d5617886087b5c8eee9df2c73381495672e23c
author Jiri Slaby <[EMAIL PROTECTED]> Thu, 08 Feb 2007 01:39:50 +0100
committer Jiri Slaby <[EMAIL PROTECTED]> Thu, 08 Feb 2007 01:39:50 +0100
drivers/video/i810/i810.h |3 ++-
drivers/video/i810/i810_main.c | 25 +++--
drivers/video/neofb.c | 21 ++---
drivers/video/riva/fbdev.c | 19 ---
drivers/video/riva/rivafb.h|3 ++-
drivers/video/vga16fb.c| 23 +++
include/video/neomagic.h |3 ++-
7 files changed, 62 insertions(+), 35 deletions(-)
diff --git a/drivers/video/i810/i810.h b/drivers/video/i810/i810.h
index 579195c..aa65ffc 100644
--- a/drivers/video/i810/i810.h
+++ b/drivers/video/i810/i810.h
@@ -264,7 +264,8 @@ struct i810fb_par {
struct heap_data cursor_heap;
struct vgastate state;
struct i810fb_i2c_chan chan[3];
- atomic_t use_count;
+ struct mutex open_lock;
+ unsigned int use_count;
u32 pseudo_palette[17];
unsigned long mmio_start_phys;
u8 __iomem *mmio_start_virtual;
diff --git a/drivers/video/i810/i810_main.c b/drivers/video/i810/i810_main.c
index b55a12d..e343c0d 100644
--- a/drivers/video/i810/i810_main.c
+++ b/drivers/video/i810/i810_main.c
@@ -1235,9 +1235,9 @@ static int i810fb_getcolreg(u8 regno, u8 *red, u8 *green,
u8 *blue,
static int i810fb_open(struct fb_info *info, int user)
{
struct i810fb_par *par = info->par;
- u32 count = atomic_read(>use_count);
-
- if (count == 0) {
+
+ mutex_lock(>open_lock);
+ if (par->use_count == 0) {
memset(>state, 0, sizeof(struct vgastate));
par->state.flags = VGA_SAVE_CMAP;
par->state.vgabase = par->mmio_start_virtual;
@@ -1246,7 +1246,8 @@ static int i810fb_open(struct fb_info *info, int user)
i810_save_vga_state(par);
}
- atomic_inc(>use_count);
+ par->use_count++;
+ mutex_unlock(>open_lock);
return 0;
}
@@ -1254,18 +1255,20 @@ static int i810fb_open(struct fb_info *info, int user)
static int i810fb_release(struct fb_info *info, int user)
{
struct i810fb_par *par = info->par;
- u32 count;
-
- count = atomic_read(>use_count);
- if (count == 0)
+
+ mutex_lock(>open_lock);
+ if (par->use_count == 0) {
+ mutex_unlock(>open_lock);
return -EINVAL;
+ }
- if (count == 1) {
+ if (par->use_count == 1) {
i810_restore_vga_state(par);
restore_vga(>state);
}
- atomic_dec(>use_count);
+ par->use_count--;
+ mutex_unlock(>open_lock);
return 0;
}
@@ -1752,6 +1755,8 @@ static void __devinit i810_init_monspecs(struct fb_info
*info)
static void __devinit i810_init_defaults(struct i810fb_par *par,
struct fb_info *info)
{
+ mutex_init(>open_lock);
+
if (voffset)
v_offset_default = voffset;
else if (par->aperture.size > 32 * 1024 * 1024)
diff --git a/drivers/video/neofb.c b/drivers/video/neofb.c
index 459ca55..395cced 100644
--- a/drivers/video/neofb.c
+++ b/drivers/video/neofb.c
@@ -556,14 +556,16 @@ static int
neofb_open(struct fb_info *info, int user)
{
struct neofb_par *par = info->par;
- int cnt = atomic_read(>ref_count);
- if (!cnt) {
+ mutex_lock(>open_lock);
+ if (!par->ref_count) {
memset(>state, 0, sizeof(struct vgastate));
par->state.flags = VGA_SAVE_MODE | VGA_SAVE_FONTS;
save_vga(>state);
}
- atomic_inc(>ref_count);
+ par->ref_count++;
+ mutex_unlock(>open_lock);
+
return 0;
}
@@ -571,14 +573,18 @@ static int
neofb_release(struct fb_info *info, int user)
{
struct neofb_par *par = info->par;
- int cnt = atomic_read(>ref_count);
- if (!cnt)
+ mutex_lock(>open_lock);
+ if (!par->ref_count) {
+ mutex_unlock(>open_lock);
return -EINVAL;
- if (cnt == 1) {
+ }
+ if (par->ref_count == 1) {
restore_vga(>state);
}
- atomic_dec(>ref_count);
+ par->ref_count--;
+ mutex_unlock(>open_lock);
+
return 0;
}
@@ -2047,6 +2053,7 @@ static struct fb_info *__devinit neo_alloc_fb_info(struct
pci_dev *dev, const st
info->fix.accel = id->driver_data;
+
[PATCH 1/2] Video: fb, add true ref_count atomicity
video/fb, add true ref_count atomicity
Some of fb drivers uses atomic_t in bad manner, since there are still some
race-prone gaps. Use mutexes to protect open/close code sections with
ref_count testing and finally use simple uint.
Signed-off-by: Jiri Slaby [EMAIL PROTECTED]
---
commit fd6de4a65b2d83db766a9ad3c137c44e361d6e0d
tree a4573d343d20988b931313c5fa35d9c370f36a05
parent e8d5617886087b5c8eee9df2c73381495672e23c
author Jiri Slaby [EMAIL PROTECTED] Thu, 08 Feb 2007 01:39:50 +0100
committer Jiri Slaby [EMAIL PROTECTED] Thu, 08 Feb 2007 01:39:50 +0100
drivers/video/i810/i810.h |3 ++-
drivers/video/i810/i810_main.c | 25 +++--
drivers/video/neofb.c | 21 ++---
drivers/video/riva/fbdev.c | 19 ---
drivers/video/riva/rivafb.h|3 ++-
drivers/video/vga16fb.c| 23 +++
include/video/neomagic.h |3 ++-
7 files changed, 62 insertions(+), 35 deletions(-)
diff --git a/drivers/video/i810/i810.h b/drivers/video/i810/i810.h
index 579195c..aa65ffc 100644
--- a/drivers/video/i810/i810.h
+++ b/drivers/video/i810/i810.h
@@ -264,7 +264,8 @@ struct i810fb_par {
struct heap_data cursor_heap;
struct vgastate state;
struct i810fb_i2c_chan chan[3];
- atomic_t use_count;
+ struct mutex open_lock;
+ unsigned int use_count;
u32 pseudo_palette[17];
unsigned long mmio_start_phys;
u8 __iomem *mmio_start_virtual;
diff --git a/drivers/video/i810/i810_main.c b/drivers/video/i810/i810_main.c
index b55a12d..e343c0d 100644
--- a/drivers/video/i810/i810_main.c
+++ b/drivers/video/i810/i810_main.c
@@ -1235,9 +1235,9 @@ static int i810fb_getcolreg(u8 regno, u8 *red, u8 *green,
u8 *blue,
static int i810fb_open(struct fb_info *info, int user)
{
struct i810fb_par *par = info-par;
- u32 count = atomic_read(par-use_count);
-
- if (count == 0) {
+
+ mutex_lock(par-open_lock);
+ if (par-use_count == 0) {
memset(par-state, 0, sizeof(struct vgastate));
par-state.flags = VGA_SAVE_CMAP;
par-state.vgabase = par-mmio_start_virtual;
@@ -1246,7 +1246,8 @@ static int i810fb_open(struct fb_info *info, int user)
i810_save_vga_state(par);
}
- atomic_inc(par-use_count);
+ par-use_count++;
+ mutex_unlock(par-open_lock);
return 0;
}
@@ -1254,18 +1255,20 @@ static int i810fb_open(struct fb_info *info, int user)
static int i810fb_release(struct fb_info *info, int user)
{
struct i810fb_par *par = info-par;
- u32 count;
-
- count = atomic_read(par-use_count);
- if (count == 0)
+
+ mutex_lock(par-open_lock);
+ if (par-use_count == 0) {
+ mutex_unlock(par-open_lock);
return -EINVAL;
+ }
- if (count == 1) {
+ if (par-use_count == 1) {
i810_restore_vga_state(par);
restore_vga(par-state);
}
- atomic_dec(par-use_count);
+ par-use_count--;
+ mutex_unlock(par-open_lock);
return 0;
}
@@ -1752,6 +1755,8 @@ static void __devinit i810_init_monspecs(struct fb_info
*info)
static void __devinit i810_init_defaults(struct i810fb_par *par,
struct fb_info *info)
{
+ mutex_init(par-open_lock);
+
if (voffset)
v_offset_default = voffset;
else if (par-aperture.size 32 * 1024 * 1024)
diff --git a/drivers/video/neofb.c b/drivers/video/neofb.c
index 459ca55..395cced 100644
--- a/drivers/video/neofb.c
+++ b/drivers/video/neofb.c
@@ -556,14 +556,16 @@ static int
neofb_open(struct fb_info *info, int user)
{
struct neofb_par *par = info-par;
- int cnt = atomic_read(par-ref_count);
- if (!cnt) {
+ mutex_lock(par-open_lock);
+ if (!par-ref_count) {
memset(par-state, 0, sizeof(struct vgastate));
par-state.flags = VGA_SAVE_MODE | VGA_SAVE_FONTS;
save_vga(par-state);
}
- atomic_inc(par-ref_count);
+ par-ref_count++;
+ mutex_unlock(par-open_lock);
+
return 0;
}
@@ -571,14 +573,18 @@ static int
neofb_release(struct fb_info *info, int user)
{
struct neofb_par *par = info-par;
- int cnt = atomic_read(par-ref_count);
- if (!cnt)
+ mutex_lock(par-open_lock);
+ if (!par-ref_count) {
+ mutex_unlock(par-open_lock);
return -EINVAL;
- if (cnt == 1) {
+ }
+ if (par-ref_count == 1) {
restore_vga(par-state);
}
- atomic_dec(par-ref_count);
+ par-ref_count--;
+ mutex_unlock(par-open_lock);
+
return 0;
}
@@ -2047,6 +2053,7 @@ static struct fb_info *__devinit neo_alloc_fb_info(struct
pci_dev *dev, const st
