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().
Signed-off-by: Figo.zhang <figo1802@xxxxxxxxx>
---
drivers/media/video/videobuf-dma-sg.c | 38
++++++++++++++++++++++++++++----
1 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/drivers/media/video/videobuf-dma-sg.c
b/drivers/media/video/videobuf-dma-sg.c
index 8359e6b..c9a8817 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -397,16 +397,44 @@ 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)
+ page = vmalloc_to_page(mem->dma.vmalloc+
+ (offset & (~PAGE_MASK)));
+ if (mem->dma.pages)
+ page = mem->dma.pages[page_nr];
+ mutex_unlock(&q->vb_lock);
+
vmf->page = page;
return 0;
--
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