From: Peter Huewe Date: Wed, 13 Jun 2012 22:21:40 +0000 (+0200) Subject: staging/xgifb: Add mutext for fb_mmap locking X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=95649c425fa2805b76f183c27aeed93f159e47cc;p=deliverable%2Flinux.git staging/xgifb: Add mutext for fb_mmap locking This adds a mutex for fb_mmap around smem_start and smem_len so the mutex inside the fb_mmap() is actually used. Changing of these fields before calling the framebuffer_register() are not mutexed. We check whether framebuffer_register has been called by reading fbinfo->count. See 537a1bf0 - "fbdev: add mutex for fb_mmap locking" by Krzysztof Helt for details. Signed-off-by: Peter Huewe Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/xgifb/XGI_main_26.c b/drivers/staging/xgifb/XGI_main_26.c index 729d980f0104..3a4328f28d07 100644 --- a/drivers/staging/xgifb/XGI_main_26.c +++ b/drivers/staging/xgifb/XGI_main_26.c @@ -1350,10 +1350,17 @@ static int XGIfb_get_fix(struct fb_fix_screeninfo *fix, int con, strncpy(fix->id, "XGI", sizeof(fix->id) - 1); - fix->smem_start = xgifb_info->video_base; + /* if register_framebuffer has been called, we must lock */ + if (atomic_read(&info->count)) + mutex_lock(&info->mm_lock); + fix->smem_start = xgifb_info->video_base; fix->smem_len = xgifb_info->video_size; + /* if register_framebuffer has been called, we can unlock */ + if (atomic_read(&info->count)) + mutex_unlock(&info->mm_lock); + fix->type = FB_TYPE_PACKED_PIXELS; fix->type_aux = 0; if (xgifb_info->video_bpp == 8)