linux/drivers/media/video/uvc
Andrea Righi 27ac792ca0 PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures
On 32-bit architectures PAGE_ALIGN() truncates 64-bit values to the 32-bit
boundary. For example:

	u64 val = PAGE_ALIGN(size);

always returns a value < 4GB even if size is greater than 4GB.

The problem resides in PAGE_MASK definition (from include/asm-x86/page.h for
example):

#define PAGE_SHIFT      12
#define PAGE_SIZE       (_AC(1,UL) << PAGE_SHIFT)
#define PAGE_MASK       (~(PAGE_SIZE-1))
...
#define PAGE_ALIGN(addr)       (((addr)+PAGE_SIZE-1)&PAGE_MASK)

The "~" is performed on a 32-bit value, so everything in "and" with
PAGE_MASK greater than 4GB will be truncated to the 32-bit boundary.
Using the ALIGN() macro seems to be the right way, because it uses
typeof(addr) for the mask.

Also move the PAGE_ALIGN() definitions out of include/asm-*/page.h in
include/linux/mm.h.

See also lkml discussion: http://lkml.org/lkml/2008/6/11/237

[akpm@linux-foundation.org: fix drivers/media/video/uvc/uvc_queue.c]
[akpm@linux-foundation.org: fix v850]
[akpm@linux-foundation.org: fix powerpc]
[akpm@linux-foundation.org: fix arm]
[akpm@linux-foundation.org: fix mips]
[akpm@linux-foundation.org: fix drivers/media/video/pvrusb2/pvrusb2-dvb.c]
[akpm@linux-foundation.org: fix drivers/mtd/maps/uclinux.c]
[akpm@linux-foundation.org: fix powerpc]
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:21 -07:00
..
Kconfig V4L/DVB (8234): uvcvideo: Make input device support optional 2008-07-20 07:18:09 -03:00
Makefile V4L/DVB (8178): uvc: Fix compilation breakage for the other drivers, if uvc is selected 2008-07-02 08:58:15 -03:00
uvc_ctrl.c v4l-dvb: remove legacy checks to allow support for kernels < 2.6.10 2008-07-20 07:17:52 -03:00
uvc_driver.c V4L/DVB (8257): uvcvideo: Fix possible AB-BA deadlock with videodev_lock and open_mutex 2008-07-20 07:19:31 -03:00
uvc_isight.c V4L/DVB (8145a): USB Video Class driver 2008-06-30 17:31:13 -03:00
uvc_queue.c PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures 2008-07-24 10:47:21 -07:00
uvc_status.c V4L/DVB (8234): uvcvideo: Make input device support optional 2008-07-20 07:18:09 -03:00
uvc_v4l2.c V4L/DVB (8256): uvc/uvc_v4l2.c: suppress uninitialized var warning 2008-07-20 07:19:26 -03:00
uvc_video.c v4l-dvb: remove legacy checks to allow support for kernels < 2.6.10 2008-07-20 07:17:52 -03:00
uvcvideo.h v4l-dvb: remove legacy checks to allow support for kernels < 2.6.10 2008-07-20 07:17:52 -03:00