Hi, On 11/17/22 07:58, Lukasz Wiecaszek wrote: > The reason behind that patch is associated with videobuf2 subsystem > (or more genrally with v4l2 framework) and user created > dma buffers (udmabuf). In some circumstances > when dealing with V4L2_MEMORY_DMABUF buffers videobuf2 subsystem > wants to use dma_buf_vmap() method on the attached dma buffer. > As udmabuf does not have .vmap operation implemented, > such dma_buf_vmap() natually fails. > > videobuf2_common: __vb2_queue_alloc: allocated 3 buffers, 1 plane(s) each > videobuf2_common: __prepare_dmabuf: buffer for plane 0 changed > videobuf2_common: __prepare_dmabuf: failed to map dmabuf for plane 0 > videobuf2_common: __buf_prepare: buffer preparation failed: -14 > > The patch itself seems to be strighforward. > It adds implementation of .vmap and .vunmap methods > to 'struct dma_buf_ops udmabuf_ops'. > .vmap method itself uses vm_map_ram() to map pages linearly > into the kernel virtual address space. > .vunmap removes mapping created earlier by .vmap. > All locking and 'vmapping counting' is done in dma_buf.c > so it seems to be redundant/unnecessary in .vmap/.vunmap. > > Signed-off-by: Lukasz Wiecaszek <lukasz.wiecaszek@xxxxxxxxx> If new patch version doesn't contain significant changes and you got acks/reviews for the previous version, then you should add the given acked-by and reviewed-by tags to the commit message by yourself. -- Best regards, Dmitry
