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Commit c4f28e54 authored by Jiri Slaby's avatar Jiri Slaby Committed by Linus Torvalds
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[PATCH] 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: default avatarJiri Slaby <jirislaby@gmail.com>
Acked-by: default avatarDenis Oliver Kropp <dok@directfb.org>
Cc: James Simmons <jsimmons@infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 52e7c922

drivers/video/i810/i810.h

+2 −1
Original line number Diff line number Diff line
@@ -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;

drivers/video/i810/i810_main.c

+15 −10
Original line number Diff line number Diff line
@@ -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)

drivers/video/neofb.c

+14 −7
Original line number Diff line number Diff line
@@ -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 


	info->fix.accel = id->driver_data;



	mutex_init(&par->open_lock);

	par->pci_burst = !nopciburst;

	par->lcd_stretch = !nostretch;

	par->libretto = libretto;

drivers/video/riva/fbdev.c

+12 −7
Original line number Diff line number Diff line
@@ -1101,10 +1101,10 @@ static int riva_get_cmap_len(const struct fb_var_screeninfo *var) 
static int rivafb_open(struct fb_info *info, int user)

{

	struct riva_par *par = info->par;

	int cnt = atomic_read(&par->ref_count);



	NVTRACE_ENTER();

	if (!cnt) {

	mutex_lock(&par->open_lock);

	if (!par->ref_count) {

#ifdef CONFIG_X86

		memset(&par->state, 0, sizeof(struct vgastate));

		par->state.flags = VGA_SAVE_MODE  | VGA_SAVE_FONTS;
@@ -1119,7 +1119,8 @@ static int rivafb_open(struct fb_info *info, int user) 
	

		riva_save_state(par, &par->initial_state);

	}

	atomic_inc(&par->ref_count);

	par->ref_count++;

	mutex_unlock(&par->open_lock);

	NVTRACE_LEAVE();

	return 0;

}
@@ -1127,12 +1128,14 @@ static int rivafb_open(struct fb_info *info, int user) 
static int rivafb_release(struct fb_info *info, int user)

{

	struct riva_par *par = info->par;

	int cnt = atomic_read(&par->ref_count);



	NVTRACE_ENTER();

	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) {

		par->riva.LockUnlock(&par->riva, 0);

		par->riva.LoadStateExt(&par->riva, &par->initial_state.ext);

		riva_load_state(par, &par->initial_state);
@@ -1141,7 +1144,8 @@ static int rivafb_release(struct fb_info *info, int user) 
#endif

		par->riva.LockUnlock(&par->riva, 1);

	}

	atomic_dec(&par->ref_count);

	par->ref_count--;

	mutex_unlock(&par->open_lock);

	NVTRACE_LEAVE();

	return 0;

}
@@ -1999,6 +2003,7 @@ static int __devinit rivafb_probe(struct pci_dev *pd, 
		goto err_disable_device;

	}



	mutex_init(&default_par->open_lock);

	default_par->riva.Architecture = riva_get_arch(pd);



	default_par->Chipset = (pd->vendor << 16) | pd->device;

drivers/video/riva/rivafb.h

+2 −1
Original line number Diff line number Diff line
@@ -53,7 +53,8 @@ struct riva_par { 
#ifdef CONFIG_X86

	struct vgastate state;

#endif

	atomic_t ref_count;

	struct mutex open_lock;

	unsigned int ref_count;

	unsigned char *EDID;

	unsigned int Chipset;

	int forceCRTC;