Commit 74c0e7cd authored by ZhangPeng's avatar ZhangPeng Committed by Ma Wupeng
Browse files

userswap: fix some type and logical bugs 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6CAIM



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

As follows, fix some type and logical bugs.
1) The type of index variable is changed from int to unsigned long to
support large memory registration.
2) Fix the bug that USWAP_PAGES_DIRTY does not take effect.
3) Take the mmap_read_lock() when using the VMA in
uswap_adjust_uffd_range().
4) Do some code refactoring and cleancode.

Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent 8c509665

fs/userfaultfd.c

+5 −6
Original line number Diff line number Diff line
@@ -1314,9 +1314,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 
	if (ret)

		goto out;

#ifdef CONFIG_USERSWAP

	if (uswap_mode)

		if (!uswap_adjust_uffd_range(&uffdio_register, &vm_flags,

					     mm)) {

	if (uswap_mode && !uswap_adjust_uffd_range(&uffdio_register,

						   &vm_flags, mm)) {

		ret = -EINVAL;

		goto out;

	}

include/linux/userswap.h

+14 −8
Original line number Diff line number Diff line
@@ -45,13 +45,18 @@ static inline bool uswap_check_copy_mode(struct vm_area_struct *vma, __u64 mode) 


static inline bool uswap_validate_mremap_flags(unsigned long flags)

{

	if (!static_branch_unlikely(&userswap_enabled) && flags & MREMAP_USWAP_SET_PTE)

	if (static_branch_unlikely(&userswap_enabled)) {

		if (flags & MREMAP_USWAP_SET_PTE &&

		    flags & ~MREMAP_USWAP_SET_PTE)

			return false;

	if (flags & MREMAP_USWAP_SET_PTE && flags & ~MREMAP_USWAP_SET_PTE)

		if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE |

			      MREMAP_DONTUNMAP | MREMAP_USWAP_SET_PTE))

			return false;

	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE | MREMAP_DONTUNMAP |

		      MREMAP_USWAP_SET_PTE))

	} else {

		if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE |

			      MREMAP_DONTUNMAP))

			return false;

	}

	return true;

}
@@ -63,7 +68,8 @@ static inline bool uswap_vm_flag_bug_on(unsigned long reason) 
	if (reason & ~(VM_UFFD_MISSING | VM_UFFD_WP | VM_USWAP))

		return true;

	if (reason & VM_USWAP)

		return !(reason & VM_UFFD_MISSING) || reason & ~(VM_USWAP|VM_UFFD_MISSING);

		return !(reason & VM_UFFD_MISSING) ||

		       reason & ~(VM_USWAP|VM_UFFD_MISSING);

	return !(reason & VM_UFFD_MISSING) ^ !!(reason & VM_UFFD_WP);

}

mm/userswap.c

+14 −8
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ static unsigned long pages_can_be_swapped(struct mm_struct *mm, 
	struct page **pages = NULL;

	unsigned long addr_end = addr + len;

	unsigned long ret;

	int i, page_num = 0;

	unsigned long i, page_num = 0;

	*ppages = NULL;
@@ -248,7 +248,7 @@ static void uswapout_recover(struct mm_struct *mm, 
	struct page *page;

	pmd_t *old_pmd, *new_pmd;

	pte_t pte;

	int i;

	unsigned long i;



	for (i = 0; i < len; i++) {

		page = pages[i];
@@ -288,7 +288,7 @@ static unsigned long do_user_swap(struct mm_struct *mm, 
	pmd_t *pmd;

	pte_t old_pte, *ptes;

	bool pages_dirty = false;

	int i = 0, j;

	unsigned long i = 0, j;

	int ret;



	ptes = kmalloc(sizeof(pte_t) * (len / PAGE_SIZE), GFP_KERNEL);
@@ -337,7 +337,7 @@ static unsigned long do_user_swap(struct mm_struct *mm, 
	}



	if (pages_dirty)

		new_addr = new_addr | USWAP_PAGES_DIRTY;

		new_addr_start = new_addr_start | USWAP_PAGES_DIRTY;

	kfree(ptes);

	return new_addr_start;
@@ -361,7 +361,7 @@ unsigned long uswap_mremap(unsigned long old_addr, unsigned long old_len, 
	struct mm_struct *mm = current->mm;

	unsigned long len = old_len;

	unsigned long ret = -EINVAL;

	int i;

	unsigned long i;



	if (!len || old_len != new_len || offset_in_page(old_addr) ||

	    (len % PAGE_SIZE))
@@ -485,22 +485,28 @@ bool uswap_adjust_uffd_range(struct uffdio_register *uffdio_register, 
{

	struct vm_area_struct *vma;

	unsigned long end;

	bool ret = false;



	if (!static_branch_unlikely(&userswap_enabled))

		return true;

	end = uffdio_register->range.start + uffdio_register->range.len - 1;



	mmap_read_lock(mm);

	vma = find_vma(mm, uffdio_register->range.start);

	if (!vma)

		return false;

		goto out_unlock;

	uffdio_register->range.start = vma->vm_start;

	vma = find_vma(mm, end);

	if (!vma)

		return false;

		goto out_unlock;

	uffdio_register->range.len = vma->vm_end - uffdio_register->range.start;



	*vm_flags |= VM_USWAP;



	return true;

	ret = true;

out_unlock:

	mmap_read_unlock(mm);

	return ret;

}



bool do_uswap_page(swp_entry_t entry, struct vm_fault *vmf,