tree f8bc0cec256e75717d36952b278181f887252041
parent b4fcdaf7654f9506f80d4e3f2b045a78333d62dc
author Hans Verkuil <hans.verkuil@cisco.com> 1386951218 -0300
committer Mauro Carvalho Chehab <m.chehab@samsung.com> 1389085204 -0200

[media] vb2: push the mmap semaphore down to __buf_prepare()

Rather than taking the mmap semaphore at a relatively high-level function,
push it down to the place where it is really needed.

It was placed in vb2_queue_or_prepare_buf() to prevent racing with other
vb2 calls. The only way I can see that a race can happen is when two
threads queue the same buffer. The solution for that it to introduce
a PREPARING state.

Moving it down offers opportunities to simplify the code.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>