Hi,
On Wednesday 28 July 2010 15:08:24 Figo.zhang wrote:
> a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping
> when it encounter page fault at video_vm_ops->fault().
>
> a new implementation for mmap, it translate the vmalloc to page at
> video_vm_ops->fault().
>
> in v2, if mem->dma.vmalloc is NULL at video_vm_ops->fault(), it will
> alloc memory by vmalloc_32().
Can you please elaborate on what you're trying to do ? What problem is this
patch supposed to fix ?
> Signed-off-by: Figo.zhang <figo1802@xxxxxxxxx>
> ---
> drivers/media/video/videobuf-dma-sg.c | 51
> +++++++++++++++++++++++++++------
> 1 files changed, 42 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/video/videobuf-dma-sg.c
> b/drivers/media/video/videobuf-dma-sg.c
> index 8359e6b..767483d 100644
> --- a/drivers/media/video/videobuf-dma-sg.c
> +++ b/drivers/media/video/videobuf-dma-sg.c
> @@ -201,10 +201,11 @@ int videobuf_dma_init_kernel(struct
> videobuf_dmabuf *dma, int direction,
> dprintk(1, "init kernel [%d pages]\n", nr_pages);
>
> dma->direction = direction;
> - dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
> - if (NULL == dma->vmalloc) {
> - dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
> - return -ENOMEM;
> + if (!dma->vmalloc)
> + dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
> + if (NULL == dma->vmalloc) {
> + dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
> + return -ENOMEM;
> }
>
> dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
> @@ -397,16 +398,48 @@ static void videobuf_vm_close(struct
> vm_area_struct *vma)
> */
> static int videobuf_vm_fault(struct vm_area_struct *vma, struct
> vm_fault *vmf)
> {
> - struct page *page;
> + struct page *page = NULL;
> + struct videobuf_mapping *map = vma->vm_private_data;
> + struct videobuf_queue *q = map->q;
> + struct videobuf_dma_sg_memory *mem = NULL;
> +
> + unsigned long offset;
> + unsigned long page_nr;
> + int first;
>
> dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
> (unsigned long)vmf->virtual_address,
> vma->vm_start, vma->vm_end);
>
> - page = alloc_page(GFP_USER | __GFP_DMA32);
> - if (!page)
> - return VM_FAULT_OOM;
> - clear_user_highpage(page, (unsigned long)vmf->virtual_address);
> + mutex_lock(&q->vb_lock);
> +
> + offset = (unsigned long)vmf->virtual_address - vma->vm_start;
> + page_nr = offset >> PAGE_SHIFT;
> +
> + for (first = 0; first < VIDEO_MAX_FRAME; first++) {
> + if (NULL == q->bufs[first])
> + continue;
> +
> + MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
> +
> + if (q->bufs[first]->map == map)
> + break;
> + }
> +
> + mem = q->bufs[first]->priv;
> + if (!mem)
> + return VM_FAULT_SIGBUS;
> + if (!mem->dma.vmalloc) {
> + mem->dma.vmalloc = vmalloc_32(PAGE_ALIGN(q->bufs[first]->size));
> + if (NULL == mem->dma.vmalloc) {
> + dprintk(1, "%s: vmalloc_32() failed\n", __func__);
> + return VM_FAULT_OOM;
> + }
> + } else
> + page = vmalloc_to_page(mem->dma.vmalloc+
> + (offset & (~PAGE_MASK)));
> + mutex_unlock(&q->vb_lock);
> +
> vmf->page = page;
>
> return 0;
--
Regards,
Laurent Pinchart
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
