mm: directly use __mlock_vma_pages_range() in find_extend_vma()
In find_extend_vma(), we don't need mlock_vma_pages_range() to verify the vma type - we know we're working with a stack. So, we can call directly into __mlock_vma_pages_range(), and remove the last make_pages_present() call site. Note that we don't use mm_populate() here, so we can't release the mmap_sem while allocating new stack pages. This is deemed acceptable, because the stack vmas grow by a bounded number of pages at a time, and these are anon pages so we don't have to read from disk to populate them. Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
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c22c0d6344
commit
cea10a19b7
5 changed files with 9 additions and 87 deletions
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@ -1035,7 +1035,6 @@ static inline int fixup_user_fault(struct task_struct *tsk,
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}
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#endif
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extern int make_pages_present(unsigned long addr, unsigned long end);
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extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
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extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
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void *buf, int len, int write);
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@ -162,8 +162,8 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
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struct vm_area_struct *prev, struct rb_node *rb_parent);
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#ifdef CONFIG_MMU
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extern long mlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end);
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extern long __mlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end, int *nonblocking);
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extern void munlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end);
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static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
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24
mm/memory.c
24
mm/memory.c
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@ -3824,30 +3824,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
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}
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#endif /* __PAGETABLE_PMD_FOLDED */
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int make_pages_present(unsigned long addr, unsigned long end)
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{
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int ret, len, write;
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struct vm_area_struct * vma;
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vma = find_vma(current->mm, addr);
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if (!vma)
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return -ENOMEM;
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/*
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* We want to touch writable mappings with a write fault in order
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* to break COW, except for shared mappings because these don't COW
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* and we would not want to dirty them for nothing.
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*/
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write = (vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE;
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BUG_ON(addr >= end);
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BUG_ON(end > vma->vm_end);
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len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
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ret = get_user_pages(current, current->mm, addr,
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len, write, 0, NULL, NULL);
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if (ret < 0)
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return ret;
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return ret == len ? 0 : -EFAULT;
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}
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#if !defined(__HAVE_ARCH_GATE_AREA)
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#if defined(AT_SYSINFO_EHDR)
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57
mm/mlock.c
57
mm/mlock.c
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@ -155,9 +155,8 @@ void munlock_vma_page(struct page *page)
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*
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* vma->vm_mm->mmap_sem must be held for at least read.
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*/
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static long __mlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end,
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int *nonblocking)
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long __mlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end, int *nonblocking)
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{
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struct mm_struct *mm = vma->vm_mm;
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unsigned long addr = start;
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@ -202,56 +201,6 @@ static int __mlock_posix_error_return(long retval)
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return retval;
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}
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/**
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* mlock_vma_pages_range() - mlock pages in specified vma range.
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* @vma - the vma containing the specfied address range
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* @start - starting address in @vma to mlock
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* @end - end address [+1] in @vma to mlock
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*
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* For mmap()/mremap()/expansion of mlocked vma.
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*
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* return 0 on success for "normal" vmas.
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*
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* return number of pages [> 0] to be removed from locked_vm on success
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* of "special" vmas.
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*/
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long mlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end)
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{
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int nr_pages = (end - start) / PAGE_SIZE;
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BUG_ON(!(vma->vm_flags & VM_LOCKED));
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/*
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* filter unlockable vmas
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*/
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if (vma->vm_flags & (VM_IO | VM_PFNMAP))
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goto no_mlock;
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if (!((vma->vm_flags & VM_DONTEXPAND) ||
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is_vm_hugetlb_page(vma) ||
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vma == get_gate_vma(current->mm))) {
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__mlock_vma_pages_range(vma, start, end, NULL);
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/* Hide errors from mmap() and other callers */
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return 0;
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}
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/*
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* User mapped kernel pages or huge pages:
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* make these pages present to populate the ptes, but
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* fall thru' to reset VM_LOCKED--no need to unlock, and
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* return nr_pages so these don't get counted against task's
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* locked limit. huge pages are already counted against
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* locked vm limit.
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*/
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make_pages_present(start, end);
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no_mlock:
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vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */
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return nr_pages; /* error or pages NOT mlocked */
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}
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/*
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* munlock_vma_pages_range() - munlock all pages in the vma range.'
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* @vma - vma containing range to be munlock()ed.
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@ -303,7 +252,7 @@ void munlock_vma_pages_range(struct vm_area_struct *vma,
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*
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* Filters out "special" vmas -- VM_LOCKED never gets set for these, and
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* munlock is a no-op. However, for some special vmas, we go ahead and
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* populate the ptes via make_pages_present().
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* populate the ptes.
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*
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* For vmas that pass the filters, merge/split as appropriate.
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*/
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10
mm/mmap.c
10
mm/mmap.c
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@ -2204,9 +2204,8 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr)
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return vma;
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if (!prev || expand_stack(prev, addr))
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return NULL;
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if (prev->vm_flags & VM_LOCKED) {
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mlock_vma_pages_range(prev, addr, prev->vm_end);
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}
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if (prev->vm_flags & VM_LOCKED)
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__mlock_vma_pages_range(prev, addr, prev->vm_end, NULL);
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return prev;
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}
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#else
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@ -2232,9 +2231,8 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr)
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start = vma->vm_start;
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if (expand_stack(vma, addr))
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return NULL;
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if (vma->vm_flags & VM_LOCKED) {
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mlock_vma_pages_range(vma, addr, start);
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}
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if (vma->vm_flags & VM_LOCKED)
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__mlock_vma_pages_range(vma, addr, start, NULL);
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return vma;
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}
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#endif
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