From: Jiri Slaby Date: Mon, 12 Feb 2007 08:55:11 +0000 (-0800) Subject: [PATCH] Video: fb, add true ref_count atomicity X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c4f28e54d61278203c2bb2aea0679e0a738235d2;p=linux-beck.git [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: Jiri Slaby Acked-by: Denis Oliver Kropp Cc: James Simmons Cc: "Antonino A. Daplas" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/video/i810/i810.h b/drivers/video/i810/i810.h index 579195c2bea3..aa65ffce915b 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 b55a12d95eb2..e343c0da9618 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 459ca553ffc0..395ccedde9a6 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 info->fix.accel = id->driver_data; + mutex_init(&par->open_lock); par->pci_burst = !nopciburst; par->lcd_stretch = !nostretch; par->libretto = libretto; diff --git a/drivers/video/riva/fbdev.c b/drivers/video/riva/fbdev.c index 1a13966b7d5b..7c19b5c2a541 100644 --- a/drivers/video/riva/fbdev.c +++ b/drivers/video/riva/fbdev.c @@ -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; diff --git a/drivers/video/riva/rivafb.h b/drivers/video/riva/rivafb.h index 7fa13fc9c413..48ead6d72f24 100644 --- a/drivers/video/riva/rivafb.h +++ b/drivers/video/riva/rivafb.h @@ -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; diff --git a/drivers/video/vga16fb.c b/drivers/video/vga16fb.c index 6aff63d5b295..ec4c7dc54a66 100644 --- a/drivers/video/vga16fb.c +++ b/drivers/video/vga16fb.c @@ -70,7 +70,8 @@ struct vga16fb_par { unsigned char ClockingMode; /* Seq-Controller:01h */ } vga_state; struct vgastate state; - atomic_t ref_count; + struct mutex open_lock; + unsigned int ref_count; int palette_blanked, vesa_blanked, mode, isVGA; u8 misc, pel_msk, vss, clkdiv; u8 crtc[VGA_CRT_C]; @@ -300,28 +301,33 @@ static void vga16fb_clock_chip(struct vga16fb_par *par, static int vga16fb_open(struct fb_info *info, int user) { struct vga16fb_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_FONTS | VGA_SAVE_MODE | VGA_SAVE_CMAP; save_vga(&par->state); } - atomic_inc(&par->ref_count); + par->ref_count++; + mutex_unlock(&par->open_lock); + return 0; } static int vga16fb_release(struct fb_info *info, int user) { struct vga16fb_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; } @@ -1357,6 +1363,7 @@ static int __init vga16fb_probe(struct platform_device *dev) printk(KERN_INFO "vga16fb: mapped to 0x%p\n", info->screen_base); par = info->par; + mutex_init(&par->open_lock); par->isVGA = ORIG_VIDEO_ISVGA; par->palette_blanked = 0; par->vesa_blanked = 0; diff --git a/include/video/neomagic.h b/include/video/neomagic.h index 78b1f15a538f..a9e118a1cd16 100644 --- a/include/video/neomagic.h +++ b/include/video/neomagic.h @@ -140,7 +140,8 @@ typedef volatile struct { struct neofb_par { struct vgastate state; - atomic_t ref_count; + struct mutex open_lock; + unsigned int ref_count; unsigned char MiscOutReg; /* Misc */ unsigned char CRTC[25]; /* Crtc Controller */