Commit 50ac952d authored by Ricardo Ribalda's avatar Ricardo Ribalda Committed by Mauro Carvalho Chehab
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[media] videobuf2-dma-sg: Support io userptr operations on io memory 



Memory exported via remap_pfn_range cannot be remapped via
get_user_pages.
Other videobuf2 methods (like the dma-contig) supports io memory.
This patch adds support for this kind of memory.
v2: Comments by Marek Szyprowski
-Use vb2_get_vma and vb2_put_vma

Signed-off-by: default avatarRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Acked-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <m.chehab@samsung.com>
parent 1380f575

drivers/media/v4l2-core/videobuf2-dma-sg.c

+47 −4
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ struct vb2_dma_sg_buf { 
	unsigned int			num_pages;

	atomic_t			refcount;

	struct vb2_vmarea_handler	handler;

	struct vm_area_struct		*vma;

};



static void vb2_dma_sg_put(void *buf_priv);
@@ -155,12 +156,18 @@ static void vb2_dma_sg_put(void *buf_priv) 
	}

}



static inline int vma_is_io(struct vm_area_struct *vma)

{

	return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));

}



static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,

				    unsigned long size, int write)

{

	struct vb2_dma_sg_buf *buf;

	unsigned long first, last;

	int num_pages_from_user;

	struct vm_area_struct *vma;



	buf = kzalloc(sizeof *buf, GFP_KERNEL);

	if (!buf)
@@ -180,6 +187,37 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, 
	if (!buf->pages)

		return NULL;



	vma = find_vma(current->mm, vaddr);

	if (!vma) {

		dprintk(1, "no vma for address %lu\n", vaddr);

		goto userptr_fail_find_vma;

	}



	if (vma->vm_end < vaddr + size) {

		dprintk(1, "vma at %lu is too small for %lu bytes\n",

			vaddr, size);

		goto userptr_fail_find_vma;

	}



	buf->vma = vb2_get_vma(vma);

	if (!buf->vma) {

		dprintk(1, "failed to copy vma\n");

		goto userptr_fail_find_vma;

	}



	if (vma_is_io(buf->vma)) {

		for (num_pages_from_user = 0;

		     num_pages_from_user < buf->num_pages;

		     ++num_pages_from_user, vaddr += PAGE_SIZE) {

			unsigned long pfn;



			if (follow_pfn(buf->vma, vaddr, &pfn)) {

				dprintk(1, "no page for address %lu\n", vaddr);

				break;

			}

			buf->pages[num_pages_from_user] = pfn_to_page(pfn);

		}

	} else

		num_pages_from_user = get_user_pages(current, current->mm,

					     vaddr & PAGE_MASK,

					     buf->num_pages,
@@ -201,8 +239,11 @@ userptr_fail_alloc_table_from_pages: 
userptr_fail_get_user_pages:

	dprintk(1, "get_user_pages requested/got: %d/%d]\n",

		buf->num_pages, num_pages_from_user);

	if (!vma_is_io(buf->vma))

		while (--num_pages_from_user >= 0)

			put_page(buf->pages[num_pages_from_user]);

	vb2_put_vma(buf->vma);

userptr_fail_find_vma:

	kfree(buf->pages);

	kfree(buf);

	return NULL;
@@ -225,9 +266,11 @@ static void vb2_dma_sg_put_userptr(void *buf_priv) 
	while (--i >= 0) {

		if (buf->write)

			set_page_dirty_lock(buf->pages[i]);

		if (!vma_is_io(buf->vma))

			put_page(buf->pages[i]);

	}

	kfree(buf->pages);

	vb2_put_vma(buf->vma);

	kfree(buf);

}

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