Commit 435cdb41 authored by Axel Rasmussen's avatar Axel Rasmussen Committed by Andrew Morton
Browse files

mm: userfaultfd: extract file size check out into a helper 

This code is already duplicated twice, and UFFDIO_POISON will do the same
check a third time.  So, it's worth extracting into a helper to save
repetitive lines of code.

Link: https://lkml.kernel.org/r/20230707215540.2324998-4-axelrasmussen@google.com


Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 2ef5d724

mm/userfaultfd.c

+20 −18
Original line number Diff line number Diff line
@@ -45,6 +45,22 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, 
	return dst_vma;

}



/* Check if dst_addr is outside of file's size. Must be called with ptl held. */

static bool mfill_file_over_size(struct vm_area_struct *dst_vma,

				 unsigned long dst_addr)

{

	struct inode *inode;

	pgoff_t offset, max_off;



	if (!dst_vma->vm_file)

		return false;



	inode = dst_vma->vm_file->f_inode;

	offset = linear_page_index(dst_vma, dst_addr);

	max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);

	return offset >= max_off;

}



/*

 * Install PTEs, to map dst_addr (within dst_vma) to page.

 *
@@ -64,8 +80,6 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, 
	bool page_in_cache = page_mapping(page);

	spinlock_t *ptl;

	struct folio *folio;

	struct inode *inode;

	pgoff_t offset, max_off;



	_dst_pte = mk_pte(page, dst_vma->vm_page_prot);

	_dst_pte = pte_mkdirty(_dst_pte);
@@ -81,13 +95,8 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, 
	if (!dst_pte)

		goto out;



	if (vma_is_shmem(dst_vma)) {

		/* serialize against truncate with the page table lock */

		inode = dst_vma->vm_file->f_inode;

		offset = linear_page_index(dst_vma, dst_addr);

		max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);

	if (mfill_file_over_size(dst_vma, dst_addr)) {

		ret = -EFAULT;

		if (unlikely(offset >= max_off))

		goto out_unlock;

	}
@@ -211,8 +220,6 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, 
	pte_t _dst_pte, *dst_pte;

	spinlock_t *ptl;

	int ret;

	pgoff_t offset, max_off;

	struct inode *inode;



	_dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),

					 dst_vma->vm_page_prot));
@@ -220,13 +227,8 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, 
	dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl);

	if (!dst_pte)

		goto out;

	if (dst_vma->vm_file) {

		/* the shmem MAP_PRIVATE case requires checking the i_size */

		inode = dst_vma->vm_file->f_inode;

		offset = linear_page_index(dst_vma, dst_addr);

		max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);

	if (mfill_file_over_size(dst_vma, dst_addr)) {

		ret = -EFAULT;

		if (unlikely(offset >= max_off))

		goto out_unlock;

	}

	ret = -EEXIST;