There's been a Linaro memory management working group for the past year to figure out memory management APIs
and unify the memory management landscape
for Linux graphics. One of the fruits of this work is now a DMA buffer sharing mechanism that was put out by Texas Instruments.
The purpose of this buffer sharing mechanism is to be able to allow various sub-systems (V4L2, GPU-accessors, DRI, etc) to share memory buffers between different devices/drivers, especially in the case of ARM SoCs and their unique design. This RFC patch-set was published by Sumit Semwal of Texas Instruments after being inspired by proof-of-concept work from Samsung and the information learned during the various Linaro memory management discussions.
This work won't be of direct interest to many, so if you're interested in learning more, hit up the mailing list
. It's possible this could be merged into the Linux 3.2 kernel, but more than likely it won't happen until the Linux 3.3 kernel or later.