mm: reorder code blocks in gup.c
This moves the actually exported functions towards the end of the file, and reorders some functions to be in more logical blocks as a preparation for moving various stubs inline into the main functionality using IS_ENABLED(). Link: http://lkml.kernel.org/r/20190625143715.1689-12-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: James Hogan <jhogan@kernel.org> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Hellwig
Linus Torvalds
parent
67a929e097
commit
d3649f68b4
410
mm/gup.c
410
mm/gup.c
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@ -1100,86 +1100,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
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return pages_done;
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}
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/*
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* We can leverage the VM_FAULT_RETRY functionality in the page fault
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* paths better by using either get_user_pages_locked() or
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* get_user_pages_unlocked().
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*
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* get_user_pages_locked() is suitable to replace the form:
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*
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* down_read(&mm->mmap_sem);
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* do_something()
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* get_user_pages(tsk, mm, ..., pages, NULL);
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* up_read(&mm->mmap_sem);
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*
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* to:
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*
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* int locked = 1;
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* down_read(&mm->mmap_sem);
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* do_something()
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* get_user_pages_locked(tsk, mm, ..., pages, &locked);
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* if (locked)
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* up_read(&mm->mmap_sem);
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*/
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long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
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unsigned int gup_flags, struct page **pages,
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int *locked)
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{
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/*
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* FIXME: Current FOLL_LONGTERM behavior is incompatible with
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* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
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* vmas. As there are no users of this flag in this call we simply
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* disallow this option for now.
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*/
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if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
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return -EINVAL;
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return __get_user_pages_locked(current, current->mm, start, nr_pages,
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pages, NULL, locked,
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gup_flags | FOLL_TOUCH);
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}
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EXPORT_SYMBOL(get_user_pages_locked);
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/*
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* get_user_pages_unlocked() is suitable to replace the form:
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*
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* down_read(&mm->mmap_sem);
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* get_user_pages(tsk, mm, ..., pages, NULL);
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* up_read(&mm->mmap_sem);
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*
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* with:
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*
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* get_user_pages_unlocked(tsk, mm, ..., pages);
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*
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* It is functionally equivalent to get_user_pages_fast so
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* get_user_pages_fast should be used instead if specific gup_flags
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* (e.g. FOLL_FORCE) are not required.
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*/
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long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
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struct page **pages, unsigned int gup_flags)
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{
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struct mm_struct *mm = current->mm;
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int locked = 1;
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long ret;
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/*
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* FIXME: Current FOLL_LONGTERM behavior is incompatible with
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* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
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* vmas. As there are no users of this flag in this call we simply
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* disallow this option for now.
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*/
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if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
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return -EINVAL;
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down_read(&mm->mmap_sem);
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ret = __get_user_pages_locked(current, mm, start, nr_pages, pages, NULL,
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&locked, gup_flags | FOLL_TOUCH);
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if (locked)
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up_read(&mm->mmap_sem);
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return ret;
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}
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EXPORT_SYMBOL(get_user_pages_unlocked);
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/*
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* get_user_pages_remote() - pin user pages in memory
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* @tsk: the task_struct to use for page fault accounting, or
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@ -1256,6 +1176,153 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
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}
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EXPORT_SYMBOL(get_user_pages_remote);
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/**
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* populate_vma_page_range() - populate a range of pages in the vma.
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* @vma: target vma
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* @start: start address
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* @end: end address
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* @nonblocking:
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*
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* This takes care of mlocking the pages too if VM_LOCKED is set.
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*
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* return 0 on success, negative error code on error.
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*
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* vma->vm_mm->mmap_sem must be held.
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*
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* If @nonblocking is NULL, it may be held for read or write and will
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* be unperturbed.
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*
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* If @nonblocking is non-NULL, it must held for read only and may be
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* released. If it's released, *@nonblocking will be set to 0.
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*/
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long populate_vma_page_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 nr_pages = (end - start) / PAGE_SIZE;
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int gup_flags;
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VM_BUG_ON(start & ~PAGE_MASK);
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VM_BUG_ON(end & ~PAGE_MASK);
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VM_BUG_ON_VMA(start < vma->vm_start, vma);
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VM_BUG_ON_VMA(end > vma->vm_end, vma);
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VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
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gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
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if (vma->vm_flags & VM_LOCKONFAULT)
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gup_flags &= ~FOLL_POPULATE;
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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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if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
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gup_flags |= FOLL_WRITE;
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/*
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* We want mlock to succeed for regions that have any permissions
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* other than PROT_NONE.
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*/
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if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))
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gup_flags |= FOLL_FORCE;
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/*
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* We made sure addr is within a VMA, so the following will
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* not result in a stack expansion that recurses back here.
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*/
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return __get_user_pages(current, mm, start, nr_pages, gup_flags,
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NULL, NULL, nonblocking);
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}
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/*
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* __mm_populate - populate and/or mlock pages within a range of address space.
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*
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* This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
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* flags. VMAs must be already marked with the desired vm_flags, and
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* mmap_sem must not be held.
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*/
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int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
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{
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struct mm_struct *mm = current->mm;
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unsigned long end, nstart, nend;
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struct vm_area_struct *vma = NULL;
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int locked = 0;
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long ret = 0;
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end = start + len;
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for (nstart = start; nstart < end; nstart = nend) {
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/*
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* We want to fault in pages for [nstart; end) address range.
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* Find first corresponding VMA.
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*/
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if (!locked) {
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locked = 1;
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, nstart);
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} else if (nstart >= vma->vm_end)
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vma = vma->vm_next;
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if (!vma || vma->vm_start >= end)
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break;
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/*
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* Set [nstart; nend) to intersection of desired address
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* range with the first VMA. Also, skip undesirable VMA types.
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*/
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nend = min(end, vma->vm_end);
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if (vma->vm_flags & (VM_IO | VM_PFNMAP))
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continue;
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if (nstart < vma->vm_start)
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nstart = vma->vm_start;
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/*
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* Now fault in a range of pages. populate_vma_page_range()
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* double checks the vma flags, so that it won't mlock pages
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* if the vma was already munlocked.
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*/
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ret = populate_vma_page_range(vma, nstart, nend, &locked);
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if (ret < 0) {
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if (ignore_errors) {
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ret = 0;
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continue; /* continue at next VMA */
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}
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break;
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}
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nend = nstart + ret * PAGE_SIZE;
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ret = 0;
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}
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if (locked)
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up_read(&mm->mmap_sem);
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return ret; /* 0 or negative error code */
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}
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/**
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* get_dump_page() - pin user page in memory while writing it to core dump
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* @addr: user address
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*
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* Returns struct page pointer of user page pinned for dump,
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* to be freed afterwards by put_page().
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*
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* Returns NULL on any kind of failure - a hole must then be inserted into
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* the corefile, to preserve alignment with its headers; and also returns
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* NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
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* allowing a hole to be left in the corefile to save diskspace.
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*
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* Called without mmap_sem, but after all other threads have been killed.
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*/
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#ifdef CONFIG_ELF_CORE
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struct page *get_dump_page(unsigned long addr)
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{
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struct vm_area_struct *vma;
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struct page *page;
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if (__get_user_pages(current, current->mm, addr, 1,
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FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
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NULL) < 1)
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return NULL;
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flush_cache_page(vma, addr, page_to_pfn(page));
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return page;
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}
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#endif /* CONFIG_ELF_CORE */
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#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
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static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
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{
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@ -1503,152 +1570,85 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
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}
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EXPORT_SYMBOL(get_user_pages);
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/**
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* populate_vma_page_range() - populate a range of pages in the vma.
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* @vma: target vma
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* @start: start address
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* @end: end address
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* @nonblocking:
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/*
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* We can leverage the VM_FAULT_RETRY functionality in the page fault
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* paths better by using either get_user_pages_locked() or
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* get_user_pages_unlocked().
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*
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* This takes care of mlocking the pages too if VM_LOCKED is set.
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* get_user_pages_locked() is suitable to replace the form:
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*
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* return 0 on success, negative error code on error.
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* down_read(&mm->mmap_sem);
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* do_something()
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* get_user_pages(tsk, mm, ..., pages, NULL);
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* up_read(&mm->mmap_sem);
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*
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* vma->vm_mm->mmap_sem must be held.
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* to:
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*
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* If @nonblocking is NULL, it may be held for read or write and will
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* be unperturbed.
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*
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* If @nonblocking is non-NULL, it must held for read only and may be
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* released. If it's released, *@nonblocking will be set to 0.
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* int locked = 1;
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* down_read(&mm->mmap_sem);
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* do_something()
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* get_user_pages_locked(tsk, mm, ..., pages, &locked);
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* if (locked)
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* up_read(&mm->mmap_sem);
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*/
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long populate_vma_page_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end, int *nonblocking)
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long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
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unsigned int gup_flags, struct page **pages,
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int *locked)
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{
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struct mm_struct *mm = vma->vm_mm;
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unsigned long nr_pages = (end - start) / PAGE_SIZE;
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int gup_flags;
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VM_BUG_ON(start & ~PAGE_MASK);
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VM_BUG_ON(end & ~PAGE_MASK);
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VM_BUG_ON_VMA(start < vma->vm_start, vma);
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VM_BUG_ON_VMA(end > vma->vm_end, vma);
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VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
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gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
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if (vma->vm_flags & VM_LOCKONFAULT)
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gup_flags &= ~FOLL_POPULATE;
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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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* FIXME: Current FOLL_LONGTERM behavior is incompatible with
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* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
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* vmas. As there are no users of this flag in this call we simply
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* disallow this option for now.
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*/
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if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
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gup_flags |= FOLL_WRITE;
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if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
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return -EINVAL;
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/*
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* We want mlock to succeed for regions that have any permissions
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* other than PROT_NONE.
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*/
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if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))
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gup_flags |= FOLL_FORCE;
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/*
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* We made sure addr is within a VMA, so the following will
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* not result in a stack expansion that recurses back here.
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*/
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return __get_user_pages(current, mm, start, nr_pages, gup_flags,
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NULL, NULL, nonblocking);
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return __get_user_pages_locked(current, current->mm, start, nr_pages,
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pages, NULL, locked,
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gup_flags | FOLL_TOUCH);
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}
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EXPORT_SYMBOL(get_user_pages_locked);
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/*
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* __mm_populate - populate and/or mlock pages within a range of address space.
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* get_user_pages_unlocked() is suitable to replace the form:
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*
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* This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
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* flags. VMAs must be already marked with the desired vm_flags, and
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* mmap_sem must not be held.
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* down_read(&mm->mmap_sem);
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* get_user_pages(tsk, mm, ..., pages, NULL);
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* up_read(&mm->mmap_sem);
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*
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* with:
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*
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* get_user_pages_unlocked(tsk, mm, ..., pages);
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*
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* It is functionally equivalent to get_user_pages_fast so
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* get_user_pages_fast should be used instead if specific gup_flags
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* (e.g. FOLL_FORCE) are not required.
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*/
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int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
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long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
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struct page **pages, unsigned int gup_flags)
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{
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struct mm_struct *mm = current->mm;
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unsigned long end, nstart, nend;
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struct vm_area_struct *vma = NULL;
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int locked = 0;
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long ret = 0;
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int locked = 1;
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long ret;
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end = start + len;
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/*
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* FIXME: Current FOLL_LONGTERM behavior is incompatible with
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* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
|
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* vmas. As there are no users of this flag in this call we simply
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* disallow this option for now.
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*/
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if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
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return -EINVAL;
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for (nstart = start; nstart < end; nstart = nend) {
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/*
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* We want to fault in pages for [nstart; end) address range.
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* Find first corresponding VMA.
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*/
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if (!locked) {
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locked = 1;
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, nstart);
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} else if (nstart >= vma->vm_end)
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vma = vma->vm_next;
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if (!vma || vma->vm_start >= end)
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break;
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/*
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* Set [nstart; nend) to intersection of desired address
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* range with the first VMA. Also, skip undesirable VMA types.
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*/
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nend = min(end, vma->vm_end);
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if (vma->vm_flags & (VM_IO | VM_PFNMAP))
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continue;
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if (nstart < vma->vm_start)
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nstart = vma->vm_start;
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/*
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* Now fault in a range of pages. populate_vma_page_range()
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* double checks the vma flags, so that it won't mlock pages
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* if the vma was already munlocked.
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*/
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ret = populate_vma_page_range(vma, nstart, nend, &locked);
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if (ret < 0) {
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if (ignore_errors) {
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ret = 0;
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continue; /* continue at next VMA */
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}
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break;
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}
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nend = nstart + ret * PAGE_SIZE;
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ret = 0;
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}
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down_read(&mm->mmap_sem);
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ret = __get_user_pages_locked(current, mm, start, nr_pages, pages, NULL,
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&locked, gup_flags | FOLL_TOUCH);
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if (locked)
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up_read(&mm->mmap_sem);
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return ret; /* 0 or negative error code */
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return ret;
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}
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/**
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* get_dump_page() - pin user page in memory while writing it to core dump
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||||
* @addr: user address
|
||||
*
|
||||
* Returns struct page pointer of user page pinned for dump,
|
||||
* to be freed afterwards by put_page().
|
||||
*
|
||||
* Returns NULL on any kind of failure - a hole must then be inserted into
|
||||
* the corefile, to preserve alignment with its headers; and also returns
|
||||
* NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
|
||||
* allowing a hole to be left in the corefile to save diskspace.
|
||||
*
|
||||
* Called without mmap_sem, but after all other threads have been killed.
|
||||
*/
|
||||
#ifdef CONFIG_ELF_CORE
|
||||
struct page *get_dump_page(unsigned long addr)
|
||||
{
|
||||
struct vm_area_struct *vma;
|
||||
struct page *page;
|
||||
|
||||
if (__get_user_pages(current, current->mm, addr, 1,
|
||||
FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
|
||||
NULL) < 1)
|
||||
return NULL;
|
||||
flush_cache_page(vma, addr, page_to_pfn(page));
|
||||
return page;
|
||||
}
|
||||
#endif /* CONFIG_ELF_CORE */
|
||||
EXPORT_SYMBOL(get_user_pages_unlocked);
|
||||
|
||||
/*
|
||||
* Fast GUP
|
||||
|
|
|
|||
Loading…
Reference in New Issue