[PATCH 02/14] staging/xgifb: Add mutext for fb_mmap locking
Peter Huewe
peterhuewe at gmx.de
Wed Jun 13 22:21:40 UTC 2012
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 <peterhuewe at gmx.de>
---
drivers/staging/xgifb/XGI_main_26.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/drivers/staging/xgifb/XGI_main_26.c b/drivers/staging/xgifb/XGI_main_26.c
index ff88f1d..f427b85 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)
--
1.7.3.4
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