The basic idea stayed the same since the last version of those patches. The exporter can provide explicit pin/unpin functions and the importer a move_notify callback. This allows us to avoid pinning buffers while importers have a mapping for them.
In difference to the last version the locking changes were separated from this patchset and committed to drm-misc-next.
This allows drivers to implement the new locking semantics without the extra unpinned handling, but of course the changed locking semantics is still a prerequisite to the unpinned handling.
The last time this set was send out the discussion ended by questioning if the move_notify callback was really the right approach of notifying the importers that a buffer is about to change its placement. A possible alternative would be to add a special crafted fence object instead.
Let's discuss on the different approaches once more,
Christian.
From: Colin Ian King <colin.king(a)canonical.com>
The -ENOTTY error return path does not free the allocated
kdata as it returns directly. Fix this by returning via the
error handling label err.
Addresses-Coverity: ("Resource leak")
Fixes: c02a81fba74f ("dma-buf: Add dma-buf heaps framework")
Signed-off-by: Colin Ian King <colin.king(a)canonical.com>
---
drivers/dma-buf/dma-heap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index 4f04d104ae61..80f2f5eac1e4 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -157,7 +157,8 @@ static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
ret = dma_heap_ioctl_allocate(file, kdata);
break;
default:
- return -ENOTTY;
+ ret = -ENOTTY;
+ goto err;
}
if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
--
2.24.0
I've spent a bit too much time reviewing all kinds of users all over
the kernel for this buffer sharing infrastructure. And some of it is
at least questionable.
Make sure we at least see when this stuff flies by.
Acked-by: Dave Airlie <airlied(a)gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com>
Cc: Sumit Semwal <sumit.semwal(a)linaro.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung(a)kernel.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Rob Herring <robh(a)kernel.org>
Cc: linux-media(a)vger.kernel.org
Cc: linaro-mm-sig(a)lists.linaro.org
---
MAINTAINERS | 1 +
1 file changed, 1 insertion(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 375dbea8bc88..c1e3da2c1947 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4941,6 +4941,7 @@ F: include/linux/dma-buf*
F: include/linux/reservation.h
F: include/linux/*fence.h
F: Documentation/driver-api/dma-buf.rst
+K: dma_(buf|fence|resv)
T: git git://anongit.freedesktop.org/drm/drm-misc
DMA GENERIC OFFLOAD ENGINE SUBSYSTEM
--
2.24.0
