Commit Graph

7 Commits

Author SHA1 Message Date
Fancy Fang
8a6a547fe1 [media] videobuf-dma-contig: set vm_pgoff to be zero to pass the sanity check in vm_iomap_memory()
When user requests V4L2_MEMORY_MMAP type buffers, the videobuf-core
will assign the corresponding offset to the 'boff' field of the
videobuf_buffer for each requested buffer sequentially. Later, user
may call mmap() to map one or all of the buffers with the 'offset'
parameter which is equal to its 'boff' value. Obviously, the 'offset'
value is only used to find the matched buffer instead of to be the
real offset from the buffer's physical start address as used by
vm_iomap_memory(). So, in some case that if the offset is not zero,
vm_iomap_memory() will fail.

Signed-off-by: Fancy Fang <chen.fang@freescale.com>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2014-10-24 09:32:41 -02:00
Ma Haijun
29f1cdb0d0 [media] videobuf-dma-contig: fix incorrect argument to vm_iomap_memory() call
The second argument should be physical address rather than virtual address.

Signed-off-by: Ma Haijun <mahaijuns@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-05-23 12:54:09 -03:00
Hans Verkuil
cca36e2eec [media] Revert "[media] videobuf_vm_{open,close} race fixes"
This reverts commit a242f42610.

That commit actually caused deadlocks, rather then fixing them.

If ext_lock is set to NULL (otherwise videobuf_queue_lock doesn't do
anything), then you get this deadlock:

The driver's mmap function calls videobuf_mmap_mapper which calls
videobuf_queue_lock on q. videobuf_mmap_mapper calls  __videobuf_mmap_mapper,
__videobuf_mmap_mapper calls videobuf_vm_open and videobuf_vm_open
calls videobuf_queue_lock on q (introduced by above patch): deadlocked.

This affects drivers using dma-contig and dma-vmalloc. Only dma-sg is
not affected since it doesn't call videobuf_vm_open from __videobuf_mmap_mapper.

Most drivers these days have a non-NULL ext_lock. Those that still use
NULL there are all fairly obscure drivers, which is why this hasn't been
seen earlier.

Since everything worked perfectly fine for many years I prefer to just
revert this patch rather than trying to fix it. videobuf is quite fragile
and I rather not touch it too much. Work is (slowly) progressing to move
everything over to vb2 or at the very least use non-NULL ext_lock in
videobuf.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: <stable@vger.kernel.org>      # for v3.11 and up
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Reported-by: Pete Eberlein <pete@sensoray.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-02-04 06:29:46 -02:00
Mauro Carvalho Chehab
2a848b2c7f [media] videobuf-dma-contig: use vm_iomap_memory()
vm_iomap_memory() provides a better end user interface than
remap_pfn_range(), as it does the needed tests before doing
mmap.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2013-05-21 09:22:12 -03:00
Al Viro
a242f42610 [media] videobuf_vm_{open,close} race fixes
just use videobuf_queue_lock(map->q) to protect map->count; vm_area_operations
->open() and ->close() are called just under vma->vm_mm->mmap_sem, which
doesn't help the drivers at all, since clonal VMAs are normally in different
address spaces...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2013-05-21 08:56:56 -03:00
Mauro Carvalho Chehab
cb132cd5d7 [media] videobuf-dma-contig: remove support for cached mem
videobuf_queue_dma_contig_init_cached() is not used anywhere.
Drop support for it, cleaning up the code a little bit.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2013-04-25 09:50:19 -03:00
Mauro Carvalho Chehab
5bc3cb743b [media] v4l: move v4l2 core into a separate directory
Currently, the v4l2 core is mixed together with other non-core drivers.
Move them into a separate directory.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-08-13 23:02:38 -03:00