Commit ea799aa4 authored by Vivek Kasireddy's avatar Vivek Kasireddy Committed by Wen Zhiwei
Browse files

udmabuf: use vmf_insert_pfn and VM_PFNMAP for handling mmap 

stable inclusion
from stable-v6.6.64
commit ac48ddf6b0232863674d38d4d0edecb40a1bda78
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBL4B6

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ac48ddf6b0232863674d38d4d0edecb40a1bda78

--------------------------------

commit 7d79cd784470395539bda91bf0b3505ff5b2ab6d upstream.

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: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Suggested-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarDave Airlie <airlied@redhat.com>
Acked-by: default avatarGerd Hoffmann <kraxel@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Junxiao Chang <junxiao.chang@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent 34ad88a9

drivers/dma-buf/udmabuf.c

+5 −3
Original line number Diff line number Diff line
@@ -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;

}