diff options
| author | Lukasz Wiecaszek <lukasz.wiecaszek@googlemail.com> | 2022-11-17 18:18:09 +0100 |
|---|---|---|
| committer | Christian König <christian.koenig@amd.com> | 2022-11-18 10:57:26 +0100 |
| commit | 7ae2e684854cd955eff8daceff84fea33a1c94be (patch) | |
| tree | a01a22ab3e792ecca06d4fc5173e7b87dfb6c7a4 /drivers/dma-buf | |
| parent | a189b2ee938f6b15ad9f95bdef63f95a3a092418 (diff) | |
udmabuf: add vmap and vunmap methods to udmabuf_ops
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@gmail.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221117171810.75637-1-lukasz.wiecaszek@gmail.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Diffstat (limited to 'drivers/dma-buf')
| -rw-r--r-- | drivers/dma-buf/udmabuf.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 283816fbd72f..740d6e426ee9 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -13,6 +13,8 @@ #include <linux/slab.h> #include <linux/udmabuf.h> #include <linux/hugetlb.h> +#include <linux/vmalloc.h> +#include <linux/iosys-map.h> static int list_limit = 1024; module_param(list_limit, int, 0644); @@ -60,6 +62,30 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma) return 0; } +static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map) +{ + struct udmabuf *ubuf = buf->priv; + void *vaddr; + + dma_resv_assert_held(buf->resv); + + vaddr = vm_map_ram(ubuf->pages, ubuf->pagecount, -1); + if (!vaddr) + return -EINVAL; + + iosys_map_set_vaddr(map, vaddr); + return 0; +} + +static void vunmap_udmabuf(struct dma_buf *buf, struct iosys_map *map) +{ + struct udmabuf *ubuf = buf->priv; + + dma_resv_assert_held(buf->resv); + + vm_unmap_ram(map->vaddr, ubuf->pagecount); +} + static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, enum dma_data_direction direction) { @@ -162,6 +188,8 @@ static const struct dma_buf_ops udmabuf_ops = { .unmap_dma_buf = unmap_udmabuf, .release = release_udmabuf, .mmap = mmap_udmabuf, + .vmap = vmap_udmabuf, + .vunmap = vunmap_udmabuf, .begin_cpu_access = begin_cpu_udmabuf, .end_cpu_access = end_cpu_udmabuf, }; |