From 7d79cd784470395539bda91bf0b3505ff5b2ab6d Mon Sep 17 00:00:00 2001 From: Vivek Kasireddy Date: Sun, 23 Jun 2024 23:36:13 -0700 Subject: [PATCH] udmabuf: use vmf_insert_pfn and VM_PFNMAP for handling mmap Add VM_PFNMAP to vm_flags in the mmap handler to ensure that the mappings would be managed without using struct page. And, in the vm_fault handler, use vmf_insert_pfn to share the page's pfn to userspace instead of directly sharing the page (via struct page *). Link: https://lkml.kernel.org/r/20240624063952.1572359-6-vivek.kasireddy@intel.com Signed-off-by: Vivek Kasireddy Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Acked-by: Dave Airlie Acked-by: Gerd Hoffmann Cc: Daniel Vetter Cc: Hugh Dickins Cc: Peter Xu Cc: Jason Gunthorpe Cc: Dongwon Kim Cc: Junxiao Chang Cc: Arnd Bergmann Cc: Christoph Hellwig Cc: Christoph Hellwig Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Oscar Salvador Cc: Shuah Khan Signed-off-by: Andrew Morton --- drivers/dma-buf/udmabuf.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index c406459996489..820c993c86592 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -35,12 +35,13 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) struct vm_area_struct *vma = vmf->vma; struct udmabuf *ubuf = vma->vm_private_data; pgoff_t pgoff = vmf->pgoff; + unsigned long pfn; if (pgoff >= ubuf->pagecount) return VM_FAULT_SIGBUS; - vmf->page = ubuf->pages[pgoff]; - get_page(vmf->page); - return 0; + + pfn = page_to_pfn(ubuf->pages[pgoff]); + return vmf_insert_pfn(vma, vmf->address, pfn); } static const struct vm_operations_struct udmabuf_vm_ops = { @@ -56,6 +57,7 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma) vma->vm_ops = &udmabuf_vm_ops; vma->vm_private_data = ubuf; + vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); return 0; }