| Message ID | 20210823122235.116189-9-senozhatsky@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | videobuf2: support new noncontiguous DMA API | expand |
Hi Sergey, On Mon, Aug 23, 2021 at 09:22:35PM +0900, Sergey Senozhatsky wrote: > This adds support for the 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 | 164 +++++++++++++++--- > 1 file changed, 138 insertions(+), 26 deletions(-) > Thanks a lot for the patch. Please see my comments inline. > diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c > index 1e218bc440c6..f1ad36b04e3a 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 non_coherent_mem; > }; > > /*********************************************/ > @@ -75,17 +77,39 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv) > return &buf->dma_addr; > } > > +/* > + * This function may fail if: > + * > + * - dma_buf_vmap() fails > + * E.g. due to lack of virtual mapping address space, or due to > + * dmabuf->ops misconfiguration. > + * > + * - dma_vmap_noncontiguous() fails > + * For instance, when requested buffer size is larger than totalram_pages(). > + * Relevant for buffers that use non-coherent memory. > + * > + * - Queue DMA attrs have DMA_ATTR_NO_KERNEL_MAPPING set > + * Relevant for buffers that use coherent memory. > + */ > 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->non_coherent_mem) > + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size, > + buf->dma_sgt); > return buf->vaddr; > } > > @@ -101,13 +125,26 @@ 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->non_coherent_mem) > + return; nit: Would it make sense to also set buf->non_coherent_mem to 1 in vb2_dc_get_userptr() and simplify this check? > + > if (!sgt) Is there a case when this would be true at this point? > 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->non_coherent_mem && buf->vaddr) Then this could check only for buf->vaddr. > + flush_kernel_vmap_range(buf->vaddr, buf->size); > } > > static void vb2_dc_finish(void *buf_priv) > @@ -115,13 +152,26 @@ static void vb2_dc_finish(void *buf_priv) Same comments as for _prepare. > 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->non_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->non_coherent_mem && buf->vaddr) > + invalidate_kernel_vmap_range(buf->vaddr, buf->size); > } > > /*********************************************/ > @@ -139,17 +189,66 @@ 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->non_coherent_mem) { > + if (buf->vaddr) > + dma_vunmap_noncontiguous(buf->dev, buf->vaddr); > + dma_free_noncontiguous(buf->dev, buf->size, > + buf->dma_sgt, buf->dma_dir); > + } else { > + dma_free_attrs(buf->dev, buf->size, buf->cookie, > + buf->dma_addr, buf->attrs); > + } > 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_vaddr() > + */ Current code now ignores the attribute, so this comment isn't entirely accurate. Maybe it's better to remove the mention of the attribute and instead say that for non_coherent buffers the kernel mapping is created on demand? > + 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 +258,28 @@ 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->non_coherent_mem = vb->vb2_queue->non_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->non_coherent_mem) > + ret = vb2_dc_alloc_non_coherent(buf); > + else > + ret = vb2_dc_alloc_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 +296,12 @@ 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->non_coherent_mem) > + ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size, > + buf->dma_sgt); > + else > + ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr, > + buf->size, buf->attrs); > if (ret) { > pr_err("Remapping memory failed, error: %d\n", ret); > return ret; > @@ -360,9 +463,15 @@ vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, > > static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map) > { > - struct vb2_dc_buf *buf = dbuf->priv; > + struct vb2_dc_buf *buf; > + void *vaddr; > + > + buf = dbuf->priv; > + vaddr = vb2_dc_vaddr(buf->vb, buf); > + if (!vaddr) > + return -EINVAL; > > - dma_buf_map_set_vaddr(map, buf->vaddr); > + dma_buf_map_set_vaddr(map, vaddr); > > return 0; > } > @@ -390,6 +499,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) > int ret; > struct sg_table *sgt; > > + if (buf->non_coherent_mem) > + return buf->dma_sgt; Wouldn't this lead to a double free in vb2_dc_put()? Best regards, Tomasz
Hi Tomasz, On (21/08/30 22:12), Tomasz Figa wrote: [..] > > + /* 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->non_coherent_mem) > > + return; > > nit: Would it make sense to also set buf->non_coherent_mem to 1 in > vb2_dc_get_userptr() and simplify this check? Sounds good. Done. > > + > > if (!sgt) > > Is there a case when this would be true at this point? We always set ->dma_sgt only for non-coherent buffers at allocation time. The rest (including this if-condition) is form the upstream code. Why was it added there. For USERPTR and coherent MMAP? > > 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->non_coherent_mem && buf->vaddr) > > Then this could check only for buf->vaddr. > > > + flush_kernel_vmap_range(buf->vaddr, buf->size); > > } > > > > static void vb2_dc_finish(void *buf_priv) > > @@ -115,13 +152,26 @@ static void vb2_dc_finish(void *buf_priv) > > Same comments as for _prepare. Done. > > +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_vaddr() > > + */ > > Current code now ignores the attribute, so this comment isn't entirely > accurate. Maybe it's better to remove the mention of the attribute and > instead say that for non_coherent buffers the kernel mapping is created on > demand? Done. > > static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map) > > { > > - struct vb2_dc_buf *buf = dbuf->priv; > > + struct vb2_dc_buf *buf; > > + void *vaddr; > > + > > + buf = dbuf->priv; > > + vaddr = vb2_dc_vaddr(buf->vb, buf); > > + if (!vaddr) > > + return -EINVAL; > > > > - dma_buf_map_set_vaddr(map, buf->vaddr); > > + dma_buf_map_set_vaddr(map, vaddr); > > > > return 0; > > } > > @@ -390,6 +499,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) > > int ret; > > struct sg_table *sgt; > > > > + if (buf->non_coherent_mem) > > + return buf->dma_sgt; > > Wouldn't this lead to a double free in vb2_dc_put()? Most likely. Done, thank you.
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c index 1e218bc440c6..f1ad36b04e3a 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 non_coherent_mem; }; /*********************************************/ @@ -75,17 +77,39 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv) return &buf->dma_addr; } +/* + * This function may fail if: + * + * - dma_buf_vmap() fails + * E.g. due to lack of virtual mapping address space, or due to + * dmabuf->ops misconfiguration. + * + * - dma_vmap_noncontiguous() fails + * For instance, when requested buffer size is larger than totalram_pages(). + * Relevant for buffers that use non-coherent memory. + * + * - Queue DMA attrs have DMA_ATTR_NO_KERNEL_MAPPING set + * Relevant for buffers that use coherent memory. + */ 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->non_coherent_mem) + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size, + buf->dma_sgt); return buf->vaddr; } @@ -101,13 +125,26 @@ 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->non_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->non_coherent_mem && buf->vaddr) + flush_kernel_vmap_range(buf->vaddr, buf->size); } static void vb2_dc_finish(void *buf_priv) @@ -115,13 +152,26 @@ 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->non_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->non_coherent_mem && buf->vaddr) + invalidate_kernel_vmap_range(buf->vaddr, buf->size); } /*********************************************/ @@ -139,17 +189,66 @@ 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->non_coherent_mem) { + if (buf->vaddr) + dma_vunmap_noncontiguous(buf->dev, buf->vaddr); + dma_free_noncontiguous(buf->dev, buf->size, + buf->dma_sgt, buf->dma_dir); + } else { + dma_free_attrs(buf->dev, buf->size, buf->cookie, + buf->dma_addr, buf->attrs); + } 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_vaddr() + */ + 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 +258,28 @@ 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->non_coherent_mem = vb->vb2_queue->non_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->non_coherent_mem) + ret = vb2_dc_alloc_non_coherent(buf); + else + ret = vb2_dc_alloc_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 +296,12 @@ 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->non_coherent_mem) + ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size, + buf->dma_sgt); + else + ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr, + buf->size, buf->attrs); if (ret) { pr_err("Remapping memory failed, error: %d\n", ret); return ret; @@ -360,9 +463,15 @@ vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map) { - struct vb2_dc_buf *buf = dbuf->priv; + struct vb2_dc_buf *buf; + void *vaddr; + + buf = dbuf->priv; + vaddr = vb2_dc_vaddr(buf->vb, buf); + if (!vaddr) + return -EINVAL; - dma_buf_map_set_vaddr(map, buf->vaddr); + dma_buf_map_set_vaddr(map, vaddr); return 0; } @@ -390,6 +499,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) int ret; struct sg_table *sgt; + if (buf->non_coherent_mem) + return buf->dma_sgt; + sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); if (!sgt) { dev_err(buf->dev, "failed to alloc sg table\n");