From c4f28e54d61278203c2bb2aea0679e0a738235d2 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 12 Feb 2007 00:55:11 -0800 Subject: [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 --- drivers/video/neofb.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'drivers/video/neofb.c') diff --git a/drivers/video/neofb.c b/drivers/video/neofb.c index 459ca553ffc..395ccedde9a 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; -- cgit v1.2.3-70-g09d2