[PATCHv4,8/8] videobuf2: handle non-contiguous DMA allocations
Commit Message
This adds support for new noncontiguous DMA API, which
requires allocators to have two execution branches: one
for the current API, and one for the new one.
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Christoph Hellwig <hch@lst.de>
---
.../common/videobuf2/videobuf2-dma-contig.c | 142 +++++++++++++++---
1 file changed, 117 insertions(+), 25 deletions(-)
Comments
On 27/07/2021 09:05, Sergey Senozhatsky wrote:
> This adds support for new noncontiguous DMA API, which
for -> for the
> requires allocators to have two execution branches: one
> for the current API, and one for the new one.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> Acked-by: Christoph Hellwig <hch@lst.de>
> ---
> .../common/videobuf2/videobuf2-dma-contig.c | 142 +++++++++++++++---
> 1 file changed, 117 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index 1e218bc440c6..10f73e27d694 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -17,6 +17,7 @@
> #include <linux/sched.h>
> #include <linux/slab.h>
> #include <linux/dma-mapping.h>
> +#include <linux/highmem.h>
>
> #include <media/videobuf2-v4l2.h>
> #include <media/videobuf2-dma-contig.h>
> @@ -42,6 +43,7 @@ struct vb2_dc_buf {
> struct dma_buf_attachment *db_attach;
>
> struct vb2_buffer *vb;
> + bool coherent_mem;
I think that this as well should be renamed to non_coherent_mem.
> };
>
> /*********************************************/
> @@ -78,14 +80,22 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
> static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> {
> struct vb2_dc_buf *buf = buf_priv;
> - struct dma_buf_map map;
> - int ret;
>
> - if (!buf->vaddr && buf->db_attach) {
> - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
> - buf->vaddr = ret ? NULL : map.vaddr;
> + if (buf->vaddr)
> + return buf->vaddr;
> +
> + if (buf->db_attach) {
> + struct dma_buf_map map;
> +
> + if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
> + buf->vaddr = map.vaddr;
> +
> + return buf->vaddr;
> }
>
> + if (!buf->coherent_mem)
> + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
> + buf->dma_sgt);
> return buf->vaddr;
> }
>
> @@ -101,13 +111,26 @@ static void vb2_dc_prepare(void *buf_priv)
> struct vb2_dc_buf *buf = buf_priv;
> struct sg_table *sgt = buf->dma_sgt;
>
> + /* This takes care of DMABUF and user-enforced cache sync hint */
> if (buf->vb->skip_cache_sync_on_prepare)
> return;
>
> + /*
> + * Coherent MMAP buffers do not need to be synced, unlike USERPTR
> + * and non-coherent MMAP buffers.
> + */
> + if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
> + return;
> +
> if (!sgt)
> return;
>
> + /* For both USERPTR and non-coherent MMAP */
> dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
> +
> + /* Non-coherent MMAP only */
> + if (!buf->coherent_mem && buf->vaddr)
> + flush_kernel_vmap_range(buf->vaddr, buf->size);
> }
>
> static void vb2_dc_finish(void *buf_priv)
> @@ -115,13 +138,26 @@ static void vb2_dc_finish(void *buf_priv)
> struct vb2_dc_buf *buf = buf_priv;
> struct sg_table *sgt = buf->dma_sgt;
>
> + /* This takes care of DMABUF and user-enforced cache sync hint */
> if (buf->vb->skip_cache_sync_on_finish)
> return;
>
> + /*
> + * Coherent MMAP buffers do not need to be synced, unlike USERPTR
> + * and non-coherent MMAP buffers.
> + */
> + if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
> + return;
> +
> if (!sgt)
> return;
>
> + /* For both USERPTR and non-coherent MMAP */
> dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
> +
> + /* Non-coherent MMAP only */
> + if (!buf->coherent_mem && buf->vaddr)
> + invalidate_kernel_vmap_range(buf->vaddr, buf->size);
> }
>
> /*********************************************/
> @@ -139,17 +175,66 @@ static void vb2_dc_put(void *buf_priv)
> sg_free_table(buf->sgt_base);
> kfree(buf->sgt_base);
> }
> - dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
> - buf->attrs);
> +
> + if (buf->coherent_mem) {
> + dma_free_attrs(buf->dev, buf->size, buf->cookie,
> + buf->dma_addr, buf->attrs);
> + } else {
> + if (buf->vaddr)
> + dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
> + dma_free_noncontiguous(buf->dev, buf->size,
> + buf->dma_sgt, buf->dma_dir);
> + }
> put_device(buf->dev);
> kfree(buf);
> }
>
> +static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
> +{
> + struct vb2_queue *q = buf->vb->vb2_queue;
> +
> + buf->cookie = dma_alloc_attrs(buf->dev,
> + buf->size,
> + &buf->dma_addr,
> + GFP_KERNEL | q->gfp_flags,
> + buf->attrs);
> + if (!buf->cookie)
> + return -ENOMEM;
> +
> + if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
> + return 0;
> +
> + buf->vaddr = buf->cookie;
> + return 0;
> +}
> +
> +static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
> +{
> + struct vb2_queue *q = buf->vb->vb2_queue;
> +
> + buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
> + buf->size,
> + buf->dma_dir,
> + GFP_KERNEL | q->gfp_flags,
> + buf->attrs);
> + if (!buf->dma_sgt)
> + return -ENOMEM;
> +
> + buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
> +
> + /*
> + * For requests that need kernel mapping (DMA_ATTR_NO_KERNEL_MAPPING
> + * bit is cleared) we perform dma_vmap_noncontiguous() in vb2_dc_vadd().
> + */
> + return 0;
> +}
> +
> static void *vb2_dc_alloc(struct vb2_buffer *vb,
> struct device *dev,
> unsigned long size)
> {
> struct vb2_dc_buf *buf;
> + int ret;
>
> if (WARN_ON(!dev))
> return ERR_PTR(-EINVAL);
> @@ -159,27 +244,28 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
> return ERR_PTR(-ENOMEM);
>
> buf->attrs = vb->vb2_queue->dma_attrs;
> - buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
> - GFP_KERNEL | vb->vb2_queue->gfp_flags,
> - buf->attrs);
> - if (!buf->cookie) {
> - dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
> - kfree(buf);
> - return ERR_PTR(-ENOMEM);
> - }
> -
> - if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
> - buf->vaddr = buf->cookie;
> + buf->dma_dir = vb->vb2_queue->dma_dir;
> + buf->vb = vb;
> + buf->coherent_mem = vb->vb2_queue->coherent_mem;
>
> + buf->size = size;
> /* Prevent the device from being released while the buffer is used */
> buf->dev = get_device(dev);
> - buf->size = size;
> - buf->dma_dir = vb->vb2_queue->dma_dir;
> +
> + if (buf->coherent_mem)
> + ret = vb2_dc_alloc_coherent(buf);
> + else
> + ret = vb2_dc_alloc_non_coherent(buf);
> +
> + if (ret) {
> + dev_err(dev, "dma alloc of size %ld failed\n", size);
> + kfree(buf);
> + return ERR_PTR(-ENOMEM);
> + }
>
> buf->handler.refcount = &buf->refcount;
> buf->handler.put = vb2_dc_put;
> buf->handler.arg = buf;
> - buf->vb = vb;
>
> refcount_set(&buf->refcount, 1);
>
> @@ -196,9 +282,12 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
> return -EINVAL;
> }
>
> - ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
> - buf->dma_addr, buf->size, buf->attrs);
> -
> + if (buf->coherent_mem)
> + ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr,
> + buf->size, buf->attrs);
> + else
> + ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size,
> + buf->dma_sgt);
> if (ret) {
> pr_err("Remapping memory failed, error: %d\n", ret);
> return ret;
> @@ -362,7 +451,7 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
> {
> struct vb2_dc_buf *buf = dbuf->priv;
>
> - dma_buf_map_set_vaddr(map, buf->vaddr);
> + dma_buf_map_set_vaddr(map, vb2_dc_vaddr(buf->vb, buf));
>
> return 0;
> }
> @@ -390,6 +479,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
> int ret;
> struct sg_table *sgt;
>
> + if (!buf->coherent_mem)
> + return buf->dma_sgt;
> +
> sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
> if (!sgt) {
> dev_err(buf->dev, "failed to alloc sg table\n");
>
Regards,
Hans
On 03/08/2021 10:33, Hans Verkuil wrote:
> On 27/07/2021 09:05, Sergey Senozhatsky wrote:
>> This adds support for new noncontiguous DMA API, which
>
> for -> for the
>
>> requires allocators to have two execution branches: one
>> for the current API, and one for the new one.
>>
>> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
>> Acked-by: Christoph Hellwig <hch@lst.de>
>> ---
>> .../common/videobuf2/videobuf2-dma-contig.c | 142 +++++++++++++++---
>> 1 file changed, 117 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
>> index 1e218bc440c6..10f73e27d694 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
>> @@ -17,6 +17,7 @@
>> #include <linux/sched.h>
>> #include <linux/slab.h>
>> #include <linux/dma-mapping.h>
>> +#include <linux/highmem.h>
>>
>> #include <media/videobuf2-v4l2.h>
>> #include <media/videobuf2-dma-contig.h>
>> @@ -42,6 +43,7 @@ struct vb2_dc_buf {
>> struct dma_buf_attachment *db_attach;
>>
>> struct vb2_buffer *vb;
>> + bool coherent_mem;
>
> I think that this as well should be renamed to non_coherent_mem.
>
>> };
>>
>> /*********************************************/
>> @@ -78,14 +80,22 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
>> static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
>> {
>> struct vb2_dc_buf *buf = buf_priv;
>> - struct dma_buf_map map;
>> - int ret;
>>
>> - if (!buf->vaddr && buf->db_attach) {
>> - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
>> - buf->vaddr = ret ? NULL : map.vaddr;
>> + if (buf->vaddr)
>> + return buf->vaddr;
>> +
>> + if (buf->db_attach) {
>> + struct dma_buf_map map;
>> +
>> + if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
>> + buf->vaddr = map.vaddr;
>> +
>> + return buf->vaddr;
>> }
>>
>> + if (!buf->coherent_mem)
>> + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
>> + buf->dma_sgt);
>> return buf->vaddr;
>> }
>>
>> @@ -101,13 +111,26 @@ static void vb2_dc_prepare(void *buf_priv)
>> struct vb2_dc_buf *buf = buf_priv;
>> struct sg_table *sgt = buf->dma_sgt;
>>
>> + /* This takes care of DMABUF and user-enforced cache sync hint */
>> if (buf->vb->skip_cache_sync_on_prepare)
>> return;
>>
>> + /*
>> + * Coherent MMAP buffers do not need to be synced, unlike USERPTR
>> + * and non-coherent MMAP buffers.
>> + */
>> + if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
>> + return;
>> +
>> if (!sgt)
>> return;
>>
>> + /* For both USERPTR and non-coherent MMAP */
>> dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
>> +
>> + /* Non-coherent MMAP only */
>> + if (!buf->coherent_mem && buf->vaddr)
>> + flush_kernel_vmap_range(buf->vaddr, buf->size);
>> }
>>
>> static void vb2_dc_finish(void *buf_priv)
>> @@ -115,13 +138,26 @@ static void vb2_dc_finish(void *buf_priv)
>> struct vb2_dc_buf *buf = buf_priv;
>> struct sg_table *sgt = buf->dma_sgt;
>>
>> + /* This takes care of DMABUF and user-enforced cache sync hint */
>> if (buf->vb->skip_cache_sync_on_finish)
>> return;
>>
>> + /*
>> + * Coherent MMAP buffers do not need to be synced, unlike USERPTR
>> + * and non-coherent MMAP buffers.
>> + */
>> + if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
>> + return;
>> +
>> if (!sgt)
>> return;
>>
>> + /* For both USERPTR and non-coherent MMAP */
>> dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
>> +
>> + /* Non-coherent MMAP only */
>> + if (!buf->coherent_mem && buf->vaddr)
>> + invalidate_kernel_vmap_range(buf->vaddr, buf->size);
>> }
>>
>> /*********************************************/
>> @@ -139,17 +175,66 @@ static void vb2_dc_put(void *buf_priv)
>> sg_free_table(buf->sgt_base);
>> kfree(buf->sgt_base);
>> }
>> - dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
>> - buf->attrs);
>> +
>> + if (buf->coherent_mem) {
>> + dma_free_attrs(buf->dev, buf->size, buf->cookie,
>> + buf->dma_addr, buf->attrs);
>> + } else {
>> + if (buf->vaddr)
>> + dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
>> + dma_free_noncontiguous(buf->dev, buf->size,
>> + buf->dma_sgt, buf->dma_dir);
>> + }
>> put_device(buf->dev);
>> kfree(buf);
>> }
>>
>> +static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
>> +{
>> + struct vb2_queue *q = buf->vb->vb2_queue;
>> +
>> + buf->cookie = dma_alloc_attrs(buf->dev,
>> + buf->size,
>> + &buf->dma_addr,
>> + GFP_KERNEL | q->gfp_flags,
>> + buf->attrs);
>> + if (!buf->cookie)
>> + return -ENOMEM;
>> +
>> + if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
>> + return 0;
>> +
>> + buf->vaddr = buf->cookie;
>> + return 0;
>> +}
>> +
>> +static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
>> +{
>> + struct vb2_queue *q = buf->vb->vb2_queue;
>> +
>> + buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
>> + buf->size,
>> + buf->dma_dir,
>> + GFP_KERNEL | q->gfp_flags,
>> + buf->attrs);
>> + if (!buf->dma_sgt)
>> + return -ENOMEM;
>> +
>> + buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
>> +
>> + /*
>> + * For requests that need kernel mapping (DMA_ATTR_NO_KERNEL_MAPPING
>> + * bit is cleared) we perform dma_vmap_noncontiguous() in vb2_dc_vadd().
Typo: vb2_dc_vadd -> vb2_dc_vaddr
Regards,
Hans
Hi Sergey,
On 27/07/2021 09:05, Sergey Senozhatsky wrote:
> This adds support for new noncontiguous DMA API, which
> requires allocators to have two execution branches: one
> for the current API, and one for the new one.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> Acked-by: Christoph Hellwig <hch@lst.de>
> ---
> .../common/videobuf2/videobuf2-dma-contig.c | 142 +++++++++++++++---
> 1 file changed, 117 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index 1e218bc440c6..10f73e27d694 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -17,6 +17,7 @@
> #include <linux/sched.h>
> #include <linux/slab.h>
> #include <linux/dma-mapping.h>
> +#include <linux/highmem.h>
>
> #include <media/videobuf2-v4l2.h>
> #include <media/videobuf2-dma-contig.h>
> @@ -42,6 +43,7 @@ struct vb2_dc_buf {
> struct dma_buf_attachment *db_attach;
>
> struct vb2_buffer *vb;
> + bool coherent_mem;
> };
>
> /*********************************************/
> @@ -78,14 +80,22 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
> static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> {
> struct vb2_dc_buf *buf = buf_priv;
> - struct dma_buf_map map;
> - int ret;
>
> - if (!buf->vaddr && buf->db_attach) {
> - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
> - buf->vaddr = ret ? NULL : map.vaddr;
> + if (buf->vaddr)
> + return buf->vaddr;
> +
> + if (buf->db_attach) {
> + struct dma_buf_map map;
> +
> + if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
> + buf->vaddr = map.vaddr;
> +
> + return buf->vaddr;
> }
>
> + if (!buf->coherent_mem)
> + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
> + buf->dma_sgt);
> return buf->vaddr;
> }
This function really needs a bunch of comments.
What I want to see here specifically is under which circumstances this function
can return NULL.
- dma_buf_vmap returns an error
- for non-coherent memory dma_vmap_noncontiguous returns an error
- coherent memory with DMA_ATTR_NO_KERNEL_MAPPING set.
In the latter case, if a buffer with coherent memory and DMA_ATTR_NO_KERNEL_MAPPING
is exported as a dma_buf, and dma_buf_vmap is called by the importer of this dma-buf,
what happens then? I think that in that case dma_buf_vmap should return an error?
See also my comment below for the vb2_dc_dmabuf_ops_vmap function.
>
> @@ -101,13 +111,26 @@ static void vb2_dc_prepare(void *buf_priv)
> struct vb2_dc_buf *buf = buf_priv;
> struct sg_table *sgt = buf->dma_sgt;
>
> + /* This takes care of DMABUF and user-enforced cache sync hint */
> if (buf->vb->skip_cache_sync_on_prepare)
> return;
>
> + /*
> + * Coherent MMAP buffers do not need to be synced, unlike USERPTR
> + * and non-coherent MMAP buffers.
> + */
> + if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
> + return;
> +
> if (!sgt)
> return;
>
> + /* For both USERPTR and non-coherent MMAP */
> dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
> +
> + /* Non-coherent MMAP only */
> + if (!buf->coherent_mem && buf->vaddr)
> + flush_kernel_vmap_range(buf->vaddr, buf->size);
> }
>
> static void vb2_dc_finish(void *buf_priv)
> @@ -115,13 +138,26 @@ static void vb2_dc_finish(void *buf_priv)
> struct vb2_dc_buf *buf = buf_priv;
> struct sg_table *sgt = buf->dma_sgt;
>
> + /* This takes care of DMABUF and user-enforced cache sync hint */
> if (buf->vb->skip_cache_sync_on_finish)
> return;
>
> + /*
> + * Coherent MMAP buffers do not need to be synced, unlike USERPTR
> + * and non-coherent MMAP buffers.
> + */
> + if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
> + return;
> +
> if (!sgt)
> return;
>
> + /* For both USERPTR and non-coherent MMAP */
> dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
> +
> + /* Non-coherent MMAP only */
> + if (!buf->coherent_mem && buf->vaddr)
> + invalidate_kernel_vmap_range(buf->vaddr, buf->size);
> }
>
> /*********************************************/
> @@ -139,17 +175,66 @@ static void vb2_dc_put(void *buf_priv)
> sg_free_table(buf->sgt_base);
> kfree(buf->sgt_base);
> }
> - dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
> - buf->attrs);
> +
> + if (buf->coherent_mem) {
> + dma_free_attrs(buf->dev, buf->size, buf->cookie,
> + buf->dma_addr, buf->attrs);
> + } else {
> + if (buf->vaddr)
> + dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
> + dma_free_noncontiguous(buf->dev, buf->size,
> + buf->dma_sgt, buf->dma_dir);
> + }
> put_device(buf->dev);
> kfree(buf);
> }
>
> +static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
> +{
> + struct vb2_queue *q = buf->vb->vb2_queue;
> +
> + buf->cookie = dma_alloc_attrs(buf->dev,
> + buf->size,
> + &buf->dma_addr,
> + GFP_KERNEL | q->gfp_flags,
> + buf->attrs);
> + if (!buf->cookie)
> + return -ENOMEM;
> +
> + if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
> + return 0;
> +
> + buf->vaddr = buf->cookie;
> + return 0;
> +}
> +
> +static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
> +{
> + struct vb2_queue *q = buf->vb->vb2_queue;
> +
> + buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
> + buf->size,
> + buf->dma_dir,
> + GFP_KERNEL | q->gfp_flags,
> + buf->attrs);
> + if (!buf->dma_sgt)
> + return -ENOMEM;
> +
> + buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
> +
> + /*
> + * For requests that need kernel mapping (DMA_ATTR_NO_KERNEL_MAPPING
> + * bit is cleared) we perform dma_vmap_noncontiguous() in vb2_dc_vadd().
> + */
> + return 0;
> +}
> +
> static void *vb2_dc_alloc(struct vb2_buffer *vb,
> struct device *dev,
> unsigned long size)
> {
> struct vb2_dc_buf *buf;
> + int ret;
>
> if (WARN_ON(!dev))
> return ERR_PTR(-EINVAL);
> @@ -159,27 +244,28 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
> return ERR_PTR(-ENOMEM);
>
> buf->attrs = vb->vb2_queue->dma_attrs;
> - buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
> - GFP_KERNEL | vb->vb2_queue->gfp_flags,
> - buf->attrs);
> - if (!buf->cookie) {
> - dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
> - kfree(buf);
> - return ERR_PTR(-ENOMEM);
> - }
> -
> - if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
> - buf->vaddr = buf->cookie;
> + buf->dma_dir = vb->vb2_queue->dma_dir;
> + buf->vb = vb;
> + buf->coherent_mem = vb->vb2_queue->coherent_mem;
>
> + buf->size = size;
> /* Prevent the device from being released while the buffer is used */
> buf->dev = get_device(dev);
> - buf->size = size;
> - buf->dma_dir = vb->vb2_queue->dma_dir;
> +
> + if (buf->coherent_mem)
> + ret = vb2_dc_alloc_coherent(buf);
> + else
> + ret = vb2_dc_alloc_non_coherent(buf);
> +
> + if (ret) {
> + dev_err(dev, "dma alloc of size %ld failed\n", size);
> + kfree(buf);
> + return ERR_PTR(-ENOMEM);
> + }
>
> buf->handler.refcount = &buf->refcount;
> buf->handler.put = vb2_dc_put;
> buf->handler.arg = buf;
> - buf->vb = vb;
>
> refcount_set(&buf->refcount, 1);
>
> @@ -196,9 +282,12 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
> return -EINVAL;
> }
>
> - ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
> - buf->dma_addr, buf->size, buf->attrs);
> -
> + if (buf->coherent_mem)
> + ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr,
> + buf->size, buf->attrs);
> + else
> + ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size,
> + buf->dma_sgt);
> if (ret) {
> pr_err("Remapping memory failed, error: %d\n", ret);
> return ret;
> @@ -362,7 +451,7 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
> {
> struct vb2_dc_buf *buf = dbuf->priv;
>
> - dma_buf_map_set_vaddr(map, buf->vaddr);
> + dma_buf_map_set_vaddr(map, vb2_dc_vaddr(buf->vb, buf));
vb2_dc_vaddr() can return NULL, shouldn't this function return an error in that case?
BTW, looking at where vb2_plane_vaddr() is called in drivers I notice that most (all?)
drivers do not check for NULL. Somewhat scary, to be honest. That's a separate issue, though.
Regards,
Hans
>
> return 0;
> }
> @@ -390,6 +479,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
> int ret;
> struct sg_table *sgt;
>
> + if (!buf->coherent_mem)
> + return buf->dma_sgt;
> +
> sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
> if (!sgt) {
> dev_err(buf->dev, "failed to alloc sg table\n");
>
Hi,
On (21/08/03 12:15), Hans Verkuil wrote:
> > static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> > {
> > struct vb2_dc_buf *buf = buf_priv;
> > - struct dma_buf_map map;
> > - int ret;
> >
> > - if (!buf->vaddr && buf->db_attach) {
> > - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
> > - buf->vaddr = ret ? NULL : map.vaddr;
> > + if (buf->vaddr)
> > + return buf->vaddr;
> > +
> > + if (buf->db_attach) {
> > + struct dma_buf_map map;
> > +
> > + if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
> > + buf->vaddr = map.vaddr;
> > +
> > + return buf->vaddr;
> > }
> >
> > + if (!buf->coherent_mem)
> > + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
> > + buf->dma_sgt);
> > return buf->vaddr;
> > }
>
> This function really needs a bunch of comments.
>
> What I want to see here specifically is under which circumstances this function
> can return NULL.
>
> - dma_buf_vmap returns an error
> - for non-coherent memory dma_vmap_noncontiguous returns an error
> - coherent memory with DMA_ATTR_NO_KERNEL_MAPPING set.
OK, I added some comments.
> In the latter case, if a buffer with coherent memory and DMA_ATTR_NO_KERNEL_MAPPING
> is exported as a dma_buf, and dma_buf_vmap is called by the importer of this dma-buf,
> what happens then? I think that in that case dma_buf_vmap should return an error?
Should we error out in vb2_dc_vaddr() in this case?
---
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index d4089d0b5ec5..e1d8ae1548fa 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -102,6 +102,9 @@ static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
if (buf->db_attach) {
struct dma_buf_map map;
+ if (WARN_ON(buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING))
+ return NULL;
+
if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
buf->vaddr = map.vaddr;
---
[..]
> > @@ -362,7 +451,7 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
> > {
> > struct vb2_dc_buf *buf = dbuf->priv;
> >
> > - dma_buf_map_set_vaddr(map, buf->vaddr);
> > + dma_buf_map_set_vaddr(map, vb2_dc_vaddr(buf->vb, buf));
>
> vb2_dc_vaddr() can return NULL, shouldn't this function return an error in that case?
Done, thanks.
> BTW, looking at where vb2_plane_vaddr() is called in drivers I notice that most (all?)
> drivers do not check for NULL. Somewhat scary, to be honest. That's a separate issue, though.
I may have some time in the future and can add missing if-s to the
drivers.
On Tue, Aug 17, 2021 at 8:57 PM Sergey Senozhatsky
<senozhatsky@chromium.org> wrote:
>
> Hi,
>
> On (21/08/03 12:15), Hans Verkuil wrote:
> > > static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> > > {
> > > struct vb2_dc_buf *buf = buf_priv;
> > > - struct dma_buf_map map;
> > > - int ret;
> > >
> > > - if (!buf->vaddr && buf->db_attach) {
> > > - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
> > > - buf->vaddr = ret ? NULL : map.vaddr;
> > > + if (buf->vaddr)
> > > + return buf->vaddr;
> > > +
> > > + if (buf->db_attach) {
> > > + struct dma_buf_map map;
> > > +
> > > + if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
> > > + buf->vaddr = map.vaddr;
> > > +
> > > + return buf->vaddr;
> > > }
> > >
> > > + if (!buf->coherent_mem)
> > > + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
> > > + buf->dma_sgt);
> > > return buf->vaddr;
> > > }
> >
> > This function really needs a bunch of comments.
> >
> > What I want to see here specifically is under which circumstances this function
> > can return NULL.
> >
> > - dma_buf_vmap returns an error
> > - for non-coherent memory dma_vmap_noncontiguous returns an error
> > - coherent memory with DMA_ATTR_NO_KERNEL_MAPPING set.
>
> OK, I added some comments.
>
> > In the latter case, if a buffer with coherent memory and DMA_ATTR_NO_KERNEL_MAPPING
> > is exported as a dma_buf, and dma_buf_vmap is called by the importer of this dma-buf,
> > what happens then? I think that in that case dma_buf_vmap should return an error?
>
> Should we error out in vb2_dc_vaddr() in this case?
Yes, because there is no way to create a kernel mapping for buffer
allocated with dma_alloc_coherent() post-factum. Of course it's not
the case for dma_alloc_noncontiguous() for which we can create the
kernel mapping on demand.
>
> ---
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index d4089d0b5ec5..e1d8ae1548fa 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -102,6 +102,9 @@ static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> if (buf->db_attach) {
> struct dma_buf_map map;
>
> + if (WARN_ON(buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING))
> + return NULL;
> +
Why here? It's the case for buffers imported _into_ vb2, not exported
from vb2 and imported to other users.
> if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
> buf->vaddr = map.vaddr;
>
>
> ---
>
>
> [..]
> > > @@ -362,7 +451,7 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
> > > {
> > > struct vb2_dc_buf *buf = dbuf->priv;
> > >
> > > - dma_buf_map_set_vaddr(map, buf->vaddr);
> > > + dma_buf_map_set_vaddr(map, vb2_dc_vaddr(buf->vb, buf));
> >
> > vb2_dc_vaddr() can return NULL, shouldn't this function return an error in that case?
>
> Done, thanks.
>
> > BTW, looking at where vb2_plane_vaddr() is called in drivers I notice that most (all?)
> > drivers do not check for NULL. Somewhat scary, to be honest. That's a separate issue, though.
>
> I may have some time in the future and can add missing if-s to the
> drivers.
On (21/08/03 10:33), Hans Verkuil wrote:
> > struct dma_buf_attachment *db_attach;
> >
> > struct vb2_buffer *vb;
> > + bool coherent_mem;
>
> I think that this as well should be renamed to non_coherent_mem.
>
Done.
On (21/08/03 10:39), Hans Verkuil wrote:
> >> +
> >> + /*
> >> + * For requests that need kernel mapping (DMA_ATTR_NO_KERNEL_MAPPING
> >> + * bit is cleared) we perform dma_vmap_noncontiguous() in vb2_dc_vadd().
>
> Typo: vb2_dc_vadd -> vb2_dc_vaddr
Done.
On (21/08/03 12:15), Hans Verkuil wrote:
> > static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> > {
> > struct vb2_dc_buf *buf = buf_priv;
> > - struct dma_buf_map map;
> > - int ret;
> >
> > - if (!buf->vaddr && buf->db_attach) {
> > - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
> > - buf->vaddr = ret ? NULL : map.vaddr;
> > + if (buf->vaddr)
> > + return buf->vaddr;
> > +
> > + if (buf->db_attach) {
> > + struct dma_buf_map map;
> > +
> > + if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
> > + buf->vaddr = map.vaddr;
> > +
> > + return buf->vaddr;
> > }
> >
> > + if (!buf->coherent_mem)
> > + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
> > + buf->dma_sgt);
> > return buf->vaddr;
> > }
>
> This function really needs a bunch of comments.
>
> What I want to see here specifically is under which circumstances this function
> can return NULL.
>
> - dma_buf_vmap returns an error
> - for non-coherent memory dma_vmap_noncontiguous returns an error
> - coherent memory with DMA_ATTR_NO_KERNEL_MAPPING set.
Done.
@@ -17,6 +17,7 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
+#include <linux/highmem.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-dma-contig.h>
@@ -42,6 +43,7 @@ struct vb2_dc_buf {
struct dma_buf_attachment *db_attach;
struct vb2_buffer *vb;
+ bool coherent_mem;
};
/*********************************************/
@@ -78,14 +80,22 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
- struct dma_buf_map map;
- int ret;
- if (!buf->vaddr && buf->db_attach) {
- ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
- buf->vaddr = ret ? NULL : map.vaddr;
+ if (buf->vaddr)
+ return buf->vaddr;
+
+ if (buf->db_attach) {
+ struct dma_buf_map map;
+
+ if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
+ buf->vaddr = map.vaddr;
+
+ return buf->vaddr;
}
+ if (!buf->coherent_mem)
+ buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
+ buf->dma_sgt);
return buf->vaddr;
}
@@ -101,13 +111,26 @@ static void vb2_dc_prepare(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
+ /* This takes care of DMABUF and user-enforced cache sync hint */
if (buf->vb->skip_cache_sync_on_prepare)
return;
+ /*
+ * Coherent MMAP buffers do not need to be synced, unlike USERPTR
+ * and non-coherent MMAP buffers.
+ */
+ if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
+ return;
+
if (!sgt)
return;
+ /* For both USERPTR and non-coherent MMAP */
dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
+
+ /* Non-coherent MMAP only */
+ if (!buf->coherent_mem && buf->vaddr)
+ flush_kernel_vmap_range(buf->vaddr, buf->size);
}
static void vb2_dc_finish(void *buf_priv)
@@ -115,13 +138,26 @@ static void vb2_dc_finish(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
+ /* This takes care of DMABUF and user-enforced cache sync hint */
if (buf->vb->skip_cache_sync_on_finish)
return;
+ /*
+ * Coherent MMAP buffers do not need to be synced, unlike USERPTR
+ * and non-coherent MMAP buffers.
+ */
+ if (buf->vb->memory == V4L2_MEMORY_MMAP && buf->coherent_mem)
+ return;
+
if (!sgt)
return;
+ /* For both USERPTR and non-coherent MMAP */
dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
+
+ /* Non-coherent MMAP only */
+ if (!buf->coherent_mem && buf->vaddr)
+ invalidate_kernel_vmap_range(buf->vaddr, buf->size);
}
/*********************************************/
@@ -139,17 +175,66 @@ static void vb2_dc_put(void *buf_priv)
sg_free_table(buf->sgt_base);
kfree(buf->sgt_base);
}
- dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
- buf->attrs);
+
+ if (buf->coherent_mem) {
+ dma_free_attrs(buf->dev, buf->size, buf->cookie,
+ buf->dma_addr, buf->attrs);
+ } else {
+ if (buf->vaddr)
+ dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
+ dma_free_noncontiguous(buf->dev, buf->size,
+ buf->dma_sgt, buf->dma_dir);
+ }
put_device(buf->dev);
kfree(buf);
}
+static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
+{
+ struct vb2_queue *q = buf->vb->vb2_queue;
+
+ buf->cookie = dma_alloc_attrs(buf->dev,
+ buf->size,
+ &buf->dma_addr,
+ GFP_KERNEL | q->gfp_flags,
+ buf->attrs);
+ if (!buf->cookie)
+ return -ENOMEM;
+
+ if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
+ return 0;
+
+ buf->vaddr = buf->cookie;
+ return 0;
+}
+
+static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
+{
+ struct vb2_queue *q = buf->vb->vb2_queue;
+
+ buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
+ buf->size,
+ buf->dma_dir,
+ GFP_KERNEL | q->gfp_flags,
+ buf->attrs);
+ if (!buf->dma_sgt)
+ return -ENOMEM;
+
+ buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
+
+ /*
+ * For requests that need kernel mapping (DMA_ATTR_NO_KERNEL_MAPPING
+ * bit is cleared) we perform dma_vmap_noncontiguous() in vb2_dc_vadd().
+ */
+ return 0;
+}
+
static void *vb2_dc_alloc(struct vb2_buffer *vb,
struct device *dev,
unsigned long size)
{
struct vb2_dc_buf *buf;
+ int ret;
if (WARN_ON(!dev))
return ERR_PTR(-EINVAL);
@@ -159,27 +244,28 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
return ERR_PTR(-ENOMEM);
buf->attrs = vb->vb2_queue->dma_attrs;
- buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
- GFP_KERNEL | vb->vb2_queue->gfp_flags,
- buf->attrs);
- if (!buf->cookie) {
- dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
- kfree(buf);
- return ERR_PTR(-ENOMEM);
- }
-
- if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
- buf->vaddr = buf->cookie;
+ buf->dma_dir = vb->vb2_queue->dma_dir;
+ buf->vb = vb;
+ buf->coherent_mem = vb->vb2_queue->coherent_mem;
+ buf->size = size;
/* Prevent the device from being released while the buffer is used */
buf->dev = get_device(dev);
- buf->size = size;
- buf->dma_dir = vb->vb2_queue->dma_dir;
+
+ if (buf->coherent_mem)
+ ret = vb2_dc_alloc_coherent(buf);
+ else
+ ret = vb2_dc_alloc_non_coherent(buf);
+
+ if (ret) {
+ dev_err(dev, "dma alloc of size %ld failed\n", size);
+ kfree(buf);
+ return ERR_PTR(-ENOMEM);
+ }
buf->handler.refcount = &buf->refcount;
buf->handler.put = vb2_dc_put;
buf->handler.arg = buf;
- buf->vb = vb;
refcount_set(&buf->refcount, 1);
@@ -196,9 +282,12 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
return -EINVAL;
}
- ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
- buf->dma_addr, buf->size, buf->attrs);
-
+ if (buf->coherent_mem)
+ ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr,
+ buf->size, buf->attrs);
+ else
+ ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size,
+ buf->dma_sgt);
if (ret) {
pr_err("Remapping memory failed, error: %d\n", ret);
return ret;
@@ -362,7 +451,7 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
{
struct vb2_dc_buf *buf = dbuf->priv;
- dma_buf_map_set_vaddr(map, buf->vaddr);
+ dma_buf_map_set_vaddr(map, vb2_dc_vaddr(buf->vb, buf));
return 0;
}
@@ -390,6 +479,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
int ret;
struct sg_table *sgt;
+ if (!buf->coherent_mem)
+ return buf->dma_sgt;
+
sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt) {
dev_err(buf->dev, "failed to alloc sg table\n");