diff options
| author | Jiri Slaby <jirislaby@gmail.com> | 2007-02-12 00:55:11 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-12 09:48:42 -0800 |
| commit | c4f28e54d61278203c2bb2aea0679e0a738235d2 (patch) | |
| tree | d92cf0718084a4e659444741443ee38afb847836 /drivers/video/neofb.c | |
| parent | 52e7c922f37907ab3cf3445b916fbbc53cbd6c75 (diff) | |
[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 <jirislaby@gmail.com>
Acked-by: Denis Oliver Kropp <dok@directfb.org>
Cc: James Simmons <jsimmons@infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video/neofb.c')
| -rw-r--r-- | drivers/video/neofb.c | 21 |
1 files changed, 14 insertions, 7 deletions
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; |