Pushed this one here to drm-misc-next.
Thanks,
Christian.
Am 17.11.22 um 18:18 schrieb Lukasz Wiecaszek:
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.
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Acked-by: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Lukasz Wiecaszek <lukasz.wiecaszek@xxxxxxxxx>
---
v1: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flinux-media%2F202211120352.G7WPASoP-lkp%40intel.com%2FT%2F%23t&data=05%7C01%7Cchristian.koenig%40amd.com%7C9ef170d657a94849986f08dac8bfeb0f%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638043023852257558%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=yml6LFzivvU1Vv4cHRf47BEeqRN%2BkH1Sy%2FN4h%2BMpRxU%3D&reserved=0
v2: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flinux-media%2F20221114052944.GA7264%40thinkpad-p72%2FT%2F%23t&data=05%7C01%7Cchristian.koenig%40amd.com%7C9ef170d657a94849986f08dac8bfeb0f%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638043023852257558%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=mBEfWp7w8wTIhO2qF7ad9GrfMyX29EM3neHNHm0i2Zc%3D&reserved=0
v3: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flinux-media%2F4f92e95f-a0dc-4eac-4c08-0df85de78ae7%40collabora.com%2FT%2F%23t&data=05%7C01%7Cchristian.koenig%40amd.com%7C9ef170d657a94849986f08dac8bfeb0f%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638043023852257558%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=2LTn8lzg48%2B%2BTK4w3vctyQ6PjUva%2BZKS8eZeLG%2FWR7I%3D&reserved=0
v4: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flinux-media%2F970e798d-ea26-5e1e-ace8-7915a866f7c7%40collabora.com%2FT%2F%23t&data=05%7C01%7Cchristian.koenig%40amd.com%7C9ef170d657a94849986f08dac8bfeb0f%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638043023852257558%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=tO4Tgd5jPeu6%2BNuWSl%2BSqF%2FEh4dI7vaah4%2FICimHvgo%3D&reserved=0
v4 -> v5: Added Acked-by and Reviewed-by to the commit message
v3 -> v4: Removed line/info 'reported by kernel test robot'
v2 -> v3: Added .vunmap to 'struct dma_buf_ops udmabuf_ops'
v1 -> v2: Patch prepared and tested against 6.1.0-rc2+
drivers/dma-buf/udmabuf.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
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,
};
