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staging/xgifb: Add mutext for fb_mmap locking

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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@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Huewe 2012-06-14 00:21:40 +02:00 committed by Greg Kroah-Hartman
parent 176f7842a8
commit 95649c425f
1 changed files with 8 additions and 1 deletions
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9
drivers/staging/xgifb/XGI_main_26.c
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@ -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)