The patch titled
Subject: udmabuf: use vmf_insert_pfn and VM_PFNMAP for handling mmap
has been added to the -mm mm-unstable branch. Its filename is
udmabuf-use-vmf_insert_pfn-and-vm_pfnmap-for-handling-mmap.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/udmabuf-use-vmf_insert_pfn-and-vm_pfnmap-for-handling-mmap.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
Subject: udmabuf: use vmf_insert_pfn and VM_PFNMAP for handling mmap
Date: Sun, 23 Jun 2024 23:36:13 -0700
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@xxxxxxxxx
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Dave Airlie <airlied@xxxxxxxxxx>
Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Dongwon Kim <dongwon.kim@xxxxxxxxx>
Cc: Junxiao Chang <junxiao.chang@xxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/dma-buf/udmabuf.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/dma-buf/udmabuf.c~udmabuf-use-vmf_insert_pfn-and-vm_pfnmap-for-handling-mmap
+++ a/drivers/dma-buf/udmabuf.c
@@ -35,12 +35,13 @@ static vm_fault_t udmabuf_vm_fault(struc
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 *
vma->vm_ops = &udmabuf_vm_ops;
vma->vm_private_data = ubuf;
+ vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
return 0;
}
_
Patches currently in -mm which might be from vivek.kasireddy@xxxxxxxxx are
mm-gup-introduce-unpin_folio-unpin_folios-helpers.patch
mm-gup-introduce-check_and_migrate_movable_folios.patch
mm-gup-introduce-memfd_pin_folios-for-pinning-memfd-folios.patch
udmabuf-use-vmf_insert_pfn-and-vm_pfnmap-for-handling-mmap.patch
udmabuf-add-back-support-for-mapping-hugetlb-pages.patch
udmabuf-convert-udmabuf-driver-to-use-folios.patch
udmabuf-pin-the-pages-using-memfd_pin_folios-api.patch
selftests-udmabuf-add-tests-to-verify-data-after-page-migration.patch
