The one in-tree videobuf2-dma-sg driver (mmp-camera) has no need for a
kernel-space mapping of the buffers; one suspects that most other drivers
would not either. The videobuf2-dma-sg module does the right thing if
buf->vaddr == NULL - it maps the buffer on demand if somebody needs it. So
let's not map the buffer at allocation time; that will save a little CPU
time and a lot of address space in the vmalloc range.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add __GFP_NOWARN parameter to videobuf2 dma-sg allocator to prevent
kernel warning and stack dump if there is not enough memory available.
Videobuf2 and drivers should correctly handle no memory case, so there
is no need for stack dump and extensive log.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Memory allocated by alloc_page() function might contain some potentially
important data from other system processes. The patch adds a flag to
zero the allocated page before giving it to videobuf2 (and then to
userspace).
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This patch fixes two minor memory leaks in videobuf2-dma-sg module. They
might happen only in case some other operations (like memory allocation)
failed.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add an implementation of DMA scatter/gather allocator and handling
routines for videobuf2.
For mmap operation mode it is implemented on top of
alloc_page + sg_set_page/_free_page.
For userptr operation mode it is implemented on top of
get_user_pages + sg_set_page/put_page.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
