| Message ID | 20230718082605.1570740-2-vivek.kasireddy@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | udmabuf: Add back support for mapping hugetlb pages (v2) | expand |
On 18.07.23 10:26, Vivek Kasireddy wrote: > 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 *). > > Cc: David Hildenbrand <david@redhat.com> > Cc: Mike Kravetz <mike.kravetz@oracle.com> > Cc: Hugh Dickins <hughd@google.com> > Cc: Peter Xu <peterx@redhat.com> > Cc: Jason Gunthorpe <jgg@nvidia.com> > Cc: Gerd Hoffmann <kraxel@redhat.com> > Cc: Dongwon Kim <dongwon.kim@intel.com> > Cc: Junxiao Chang <junxiao.chang@intel.com> > Suggested-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com> > --- > 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 c40645999648..820c993c8659 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; > } > Looks reasonable to me. Acked-by: David Hildenbrand <david@redhat.com>
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index c40645999648..820c993c8659 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; }
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 *). Cc: David Hildenbrand <david@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Dongwon Kim <dongwon.kim@intel.com> Cc: Junxiao Chang <junxiao.chang@intel.com> Suggested-by: David Hildenbrand <david@redhat.com> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com> --- drivers/dma-buf/udmabuf.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)