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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
645 lines
17 KiB
C
645 lines
17 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* mm/mremap.c
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*
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* (C) Copyright 1996 Linus Torvalds
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*
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* Address space accounting code <alan@lxorguk.ukuu.org.uk>
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* (C) Copyright 2002 Red Hat Inc, All Rights Reserved
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*/
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/shm.h>
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#include <linux/ksm.h>
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#include <linux/mman.h>
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#include <linux/swap.h>
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#include <linux/capability.h>
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#include <linux/fs.h>
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#include <linux/swapops.h>
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#include <linux/highmem.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/mmu_notifier.h>
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#include <linux/uaccess.h>
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#include <linux/mm-arch-hooks.h>
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#include <linux/userfaultfd_k.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include "internal.h"
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static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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pgd = pgd_offset(mm, addr);
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if (pgd_none_or_clear_bad(pgd))
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return NULL;
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p4d = p4d_offset(pgd, addr);
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if (p4d_none_or_clear_bad(p4d))
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return NULL;
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pud = pud_offset(p4d, addr);
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if (pud_none_or_clear_bad(pud))
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return NULL;
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pmd = pmd_offset(pud, addr);
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if (pmd_none(*pmd))
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return NULL;
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return pmd;
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}
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static pmd_t *alloc_new_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
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unsigned long addr)
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{
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pgd_t *pgd;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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pgd = pgd_offset(mm, addr);
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p4d = p4d_alloc(mm, pgd, addr);
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if (!p4d)
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return NULL;
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pud = pud_alloc(mm, p4d, addr);
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if (!pud)
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return NULL;
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pmd = pmd_alloc(mm, pud, addr);
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if (!pmd)
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return NULL;
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VM_BUG_ON(pmd_trans_huge(*pmd));
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return pmd;
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}
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static void take_rmap_locks(struct vm_area_struct *vma)
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{
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if (vma->vm_file)
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i_mmap_lock_write(vma->vm_file->f_mapping);
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if (vma->anon_vma)
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anon_vma_lock_write(vma->anon_vma);
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}
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static void drop_rmap_locks(struct vm_area_struct *vma)
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{
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if (vma->anon_vma)
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anon_vma_unlock_write(vma->anon_vma);
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if (vma->vm_file)
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i_mmap_unlock_write(vma->vm_file->f_mapping);
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}
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static pte_t move_soft_dirty_pte(pte_t pte)
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{
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/*
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* Set soft dirty bit so we can notice
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* in userspace the ptes were moved.
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*/
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#ifdef CONFIG_MEM_SOFT_DIRTY
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if (pte_present(pte))
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pte = pte_mksoft_dirty(pte);
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else if (is_swap_pte(pte))
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pte = pte_swp_mksoft_dirty(pte);
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#endif
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return pte;
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}
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static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
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unsigned long old_addr, unsigned long old_end,
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struct vm_area_struct *new_vma, pmd_t *new_pmd,
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unsigned long new_addr, bool need_rmap_locks, bool *need_flush)
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{
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struct mm_struct *mm = vma->vm_mm;
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pte_t *old_pte, *new_pte, pte;
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spinlock_t *old_ptl, *new_ptl;
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bool force_flush = false;
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unsigned long len = old_end - old_addr;
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/*
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* When need_rmap_locks is true, we take the i_mmap_rwsem and anon_vma
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* locks to ensure that rmap will always observe either the old or the
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* new ptes. This is the easiest way to avoid races with
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* truncate_pagecache(), page migration, etc...
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*
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* When need_rmap_locks is false, we use other ways to avoid
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* such races:
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*
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* - During exec() shift_arg_pages(), we use a specially tagged vma
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* which rmap call sites look for using is_vma_temporary_stack().
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*
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* - During mremap(), new_vma is often known to be placed after vma
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* in rmap traversal order. This ensures rmap will always observe
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* either the old pte, or the new pte, or both (the page table locks
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* serialize access to individual ptes, but only rmap traversal
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* order guarantees that we won't miss both the old and new ptes).
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*/
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if (need_rmap_locks)
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take_rmap_locks(vma);
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/*
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* We don't have to worry about the ordering of src and dst
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* pte locks because exclusive mmap_sem prevents deadlock.
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*/
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old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
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new_pte = pte_offset_map(new_pmd, new_addr);
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new_ptl = pte_lockptr(mm, new_pmd);
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if (new_ptl != old_ptl)
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spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
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flush_tlb_batched_pending(vma->vm_mm);
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arch_enter_lazy_mmu_mode();
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for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
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new_pte++, new_addr += PAGE_SIZE) {
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if (pte_none(*old_pte))
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continue;
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pte = ptep_get_and_clear(mm, old_addr, old_pte);
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/*
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* If we are remapping a dirty PTE, make sure
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* to flush TLB before we drop the PTL for the
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* old PTE or we may race with page_mkclean().
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*
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* This check has to be done after we removed the
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* old PTE from page tables or another thread may
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* dirty it after the check and before the removal.
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*/
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if (pte_present(pte) && pte_dirty(pte))
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force_flush = true;
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pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr);
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pte = move_soft_dirty_pte(pte);
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set_pte_at(mm, new_addr, new_pte, pte);
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}
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arch_leave_lazy_mmu_mode();
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if (new_ptl != old_ptl)
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spin_unlock(new_ptl);
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pte_unmap(new_pte - 1);
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if (force_flush)
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flush_tlb_range(vma, old_end - len, old_end);
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else
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*need_flush = true;
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pte_unmap_unlock(old_pte - 1, old_ptl);
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if (need_rmap_locks)
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drop_rmap_locks(vma);
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}
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#define LATENCY_LIMIT (64 * PAGE_SIZE)
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unsigned long move_page_tables(struct vm_area_struct *vma,
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unsigned long old_addr, struct vm_area_struct *new_vma,
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unsigned long new_addr, unsigned long len,
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bool need_rmap_locks)
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{
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unsigned long extent, next, old_end;
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pmd_t *old_pmd, *new_pmd;
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bool need_flush = false;
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unsigned long mmun_start; /* For mmu_notifiers */
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unsigned long mmun_end; /* For mmu_notifiers */
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old_end = old_addr + len;
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flush_cache_range(vma, old_addr, old_end);
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mmun_start = old_addr;
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mmun_end = old_end;
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mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end);
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for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
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cond_resched();
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next = (old_addr + PMD_SIZE) & PMD_MASK;
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/* even if next overflowed, extent below will be ok */
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extent = next - old_addr;
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if (extent > old_end - old_addr)
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extent = old_end - old_addr;
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old_pmd = get_old_pmd(vma->vm_mm, old_addr);
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if (!old_pmd)
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continue;
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new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr);
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if (!new_pmd)
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break;
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if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) {
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if (extent == HPAGE_PMD_SIZE) {
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bool moved;
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/* See comment in move_ptes() */
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if (need_rmap_locks)
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take_rmap_locks(vma);
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moved = move_huge_pmd(vma, old_addr, new_addr,
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old_end, old_pmd, new_pmd,
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&need_flush);
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if (need_rmap_locks)
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drop_rmap_locks(vma);
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if (moved)
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continue;
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}
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split_huge_pmd(vma, old_pmd, old_addr);
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if (pmd_trans_unstable(old_pmd))
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continue;
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}
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if (pte_alloc(new_vma->vm_mm, new_pmd, new_addr))
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break;
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next = (new_addr + PMD_SIZE) & PMD_MASK;
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if (extent > next - new_addr)
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extent = next - new_addr;
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if (extent > LATENCY_LIMIT)
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extent = LATENCY_LIMIT;
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move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma,
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new_pmd, new_addr, need_rmap_locks, &need_flush);
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}
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if (need_flush)
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flush_tlb_range(vma, old_end-len, old_addr);
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mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
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return len + old_addr - old_end; /* how much done */
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}
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static unsigned long move_vma(struct vm_area_struct *vma,
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unsigned long old_addr, unsigned long old_len,
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unsigned long new_len, unsigned long new_addr,
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bool *locked, struct vm_userfaultfd_ctx *uf,
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struct list_head *uf_unmap)
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{
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struct mm_struct *mm = vma->vm_mm;
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struct vm_area_struct *new_vma;
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unsigned long vm_flags = vma->vm_flags;
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unsigned long new_pgoff;
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unsigned long moved_len;
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unsigned long excess = 0;
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unsigned long hiwater_vm;
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int split = 0;
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int err;
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bool need_rmap_locks;
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/*
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* We'd prefer to avoid failure later on in do_munmap:
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* which may split one vma into three before unmapping.
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*/
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if (mm->map_count >= sysctl_max_map_count - 3)
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return -ENOMEM;
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/*
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* Advise KSM to break any KSM pages in the area to be moved:
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* it would be confusing if they were to turn up at the new
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* location, where they happen to coincide with different KSM
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* pages recently unmapped. But leave vma->vm_flags as it was,
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* so KSM can come around to merge on vma and new_vma afterwards.
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*/
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err = ksm_madvise(vma, old_addr, old_addr + old_len,
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MADV_UNMERGEABLE, &vm_flags);
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if (err)
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return err;
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new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
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new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff,
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&need_rmap_locks);
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if (!new_vma)
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return -ENOMEM;
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moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len,
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need_rmap_locks);
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if (moved_len < old_len) {
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err = -ENOMEM;
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} else if (vma->vm_ops && vma->vm_ops->mremap) {
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err = vma->vm_ops->mremap(new_vma);
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}
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if (unlikely(err)) {
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/*
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* On error, move entries back from new area to old,
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* which will succeed since page tables still there,
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* and then proceed to unmap new area instead of old.
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*/
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move_page_tables(new_vma, new_addr, vma, old_addr, moved_len,
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true);
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vma = new_vma;
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old_len = new_len;
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old_addr = new_addr;
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new_addr = err;
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} else {
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mremap_userfaultfd_prep(new_vma, uf);
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arch_remap(mm, old_addr, old_addr + old_len,
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new_addr, new_addr + new_len);
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}
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/* Conceal VM_ACCOUNT so old reservation is not undone */
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if (vm_flags & VM_ACCOUNT) {
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vma->vm_flags &= ~VM_ACCOUNT;
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excess = vma->vm_end - vma->vm_start - old_len;
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if (old_addr > vma->vm_start &&
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old_addr + old_len < vma->vm_end)
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split = 1;
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}
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/*
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* If we failed to move page tables we still do total_vm increment
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* since do_munmap() will decrement it by old_len == new_len.
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*
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* Since total_vm is about to be raised artificially high for a
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* moment, we need to restore high watermark afterwards: if stats
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* are taken meanwhile, total_vm and hiwater_vm appear too high.
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* If this were a serious issue, we'd add a flag to do_munmap().
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*/
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hiwater_vm = mm->hiwater_vm;
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vm_stat_account(mm, vma->vm_flags, new_len >> PAGE_SHIFT);
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/* Tell pfnmap has moved from this vma */
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if (unlikely(vma->vm_flags & VM_PFNMAP))
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untrack_pfn_moved(vma);
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if (do_munmap(mm, old_addr, old_len, uf_unmap) < 0) {
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/* OOM: unable to split vma, just get accounts right */
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vm_unacct_memory(excess >> PAGE_SHIFT);
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excess = 0;
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}
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mm->hiwater_vm = hiwater_vm;
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/* Restore VM_ACCOUNT if one or two pieces of vma left */
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if (excess) {
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vma->vm_flags |= VM_ACCOUNT;
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if (split)
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vma->vm_next->vm_flags |= VM_ACCOUNT;
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}
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if (vm_flags & VM_LOCKED) {
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mm->locked_vm += new_len >> PAGE_SHIFT;
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*locked = true;
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}
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return new_addr;
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}
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static struct vm_area_struct *vma_to_resize(unsigned long addr,
|
|
unsigned long old_len, unsigned long new_len, unsigned long *p)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma = find_vma(mm, addr);
|
|
unsigned long pgoff;
|
|
|
|
if (!vma || vma->vm_start > addr)
|
|
return ERR_PTR(-EFAULT);
|
|
|
|
/*
|
|
* !old_len is a special case where an attempt is made to 'duplicate'
|
|
* a mapping. This makes no sense for private mappings as it will
|
|
* instead create a fresh/new mapping unrelated to the original. This
|
|
* is contrary to the basic idea of mremap which creates new mappings
|
|
* based on the original. There are no known use cases for this
|
|
* behavior. As a result, fail such attempts.
|
|
*/
|
|
if (!old_len && !(vma->vm_flags & (VM_SHARED | VM_MAYSHARE))) {
|
|
pr_warn_once("%s (%d): attempted to duplicate a private mapping with mremap. This is not supported.\n", current->comm, current->pid);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (is_vm_hugetlb_page(vma))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
/* We can't remap across vm area boundaries */
|
|
if (old_len > vma->vm_end - addr)
|
|
return ERR_PTR(-EFAULT);
|
|
|
|
if (new_len == old_len)
|
|
return vma;
|
|
|
|
/* Need to be careful about a growing mapping */
|
|
pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
|
|
pgoff += vma->vm_pgoff;
|
|
if (pgoff + (new_len >> PAGE_SHIFT) < pgoff)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
|
|
return ERR_PTR(-EFAULT);
|
|
|
|
if (vma->vm_flags & VM_LOCKED) {
|
|
unsigned long locked, lock_limit;
|
|
locked = mm->locked_vm << PAGE_SHIFT;
|
|
lock_limit = rlimit(RLIMIT_MEMLOCK);
|
|
locked += new_len - old_len;
|
|
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
|
|
return ERR_PTR(-EAGAIN);
|
|
}
|
|
|
|
if (!may_expand_vm(mm, vma->vm_flags,
|
|
(new_len - old_len) >> PAGE_SHIFT))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (vma->vm_flags & VM_ACCOUNT) {
|
|
unsigned long charged = (new_len - old_len) >> PAGE_SHIFT;
|
|
if (security_vm_enough_memory_mm(mm, charged))
|
|
return ERR_PTR(-ENOMEM);
|
|
*p = charged;
|
|
}
|
|
|
|
return vma;
|
|
}
|
|
|
|
static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
|
|
unsigned long new_addr, unsigned long new_len, bool *locked,
|
|
struct vm_userfaultfd_ctx *uf,
|
|
struct list_head *uf_unmap_early,
|
|
struct list_head *uf_unmap)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma;
|
|
unsigned long ret = -EINVAL;
|
|
unsigned long charged = 0;
|
|
unsigned long map_flags;
|
|
|
|
if (offset_in_page(new_addr))
|
|
goto out;
|
|
|
|
if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
|
|
goto out;
|
|
|
|
/* Ensure the old/new locations do not overlap */
|
|
if (addr + old_len > new_addr && new_addr + new_len > addr)
|
|
goto out;
|
|
|
|
ret = do_munmap(mm, new_addr, new_len, uf_unmap_early);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (old_len >= new_len) {
|
|
ret = do_munmap(mm, addr+new_len, old_len - new_len, uf_unmap);
|
|
if (ret && old_len != new_len)
|
|
goto out;
|
|
old_len = new_len;
|
|
}
|
|
|
|
vma = vma_to_resize(addr, old_len, new_len, &charged);
|
|
if (IS_ERR(vma)) {
|
|
ret = PTR_ERR(vma);
|
|
goto out;
|
|
}
|
|
|
|
map_flags = MAP_FIXED;
|
|
if (vma->vm_flags & VM_MAYSHARE)
|
|
map_flags |= MAP_SHARED;
|
|
|
|
ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
|
|
((addr - vma->vm_start) >> PAGE_SHIFT),
|
|
map_flags);
|
|
if (offset_in_page(ret))
|
|
goto out1;
|
|
|
|
ret = move_vma(vma, addr, old_len, new_len, new_addr, locked, uf,
|
|
uf_unmap);
|
|
if (!(offset_in_page(ret)))
|
|
goto out;
|
|
out1:
|
|
vm_unacct_memory(charged);
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
|
|
{
|
|
unsigned long end = vma->vm_end + delta;
|
|
if (end < vma->vm_end) /* overflow */
|
|
return 0;
|
|
if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */
|
|
return 0;
|
|
if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
|
|
0, MAP_FIXED) & ~PAGE_MASK)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Expand (or shrink) an existing mapping, potentially moving it at the
|
|
* same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
|
|
*
|
|
* MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
|
|
* This option implies MREMAP_MAYMOVE.
|
|
*/
|
|
SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
|
|
unsigned long, new_len, unsigned long, flags,
|
|
unsigned long, new_addr)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma;
|
|
unsigned long ret = -EINVAL;
|
|
unsigned long charged = 0;
|
|
bool locked = false;
|
|
struct vm_userfaultfd_ctx uf = NULL_VM_UFFD_CTX;
|
|
LIST_HEAD(uf_unmap_early);
|
|
LIST_HEAD(uf_unmap);
|
|
|
|
if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
|
|
return ret;
|
|
|
|
if (flags & MREMAP_FIXED && !(flags & MREMAP_MAYMOVE))
|
|
return ret;
|
|
|
|
if (offset_in_page(addr))
|
|
return ret;
|
|
|
|
old_len = PAGE_ALIGN(old_len);
|
|
new_len = PAGE_ALIGN(new_len);
|
|
|
|
/*
|
|
* We allow a zero old-len as a special case
|
|
* for DOS-emu "duplicate shm area" thing. But
|
|
* a zero new-len is nonsensical.
|
|
*/
|
|
if (!new_len)
|
|
return ret;
|
|
|
|
if (down_write_killable(¤t->mm->mmap_sem))
|
|
return -EINTR;
|
|
|
|
if (flags & MREMAP_FIXED) {
|
|
ret = mremap_to(addr, old_len, new_addr, new_len,
|
|
&locked, &uf, &uf_unmap_early, &uf_unmap);
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Always allow a shrinking remap: that just unmaps
|
|
* the unnecessary pages..
|
|
* do_munmap does all the needed commit accounting
|
|
*/
|
|
if (old_len >= new_len) {
|
|
ret = do_munmap(mm, addr+new_len, old_len - new_len, &uf_unmap);
|
|
if (ret && old_len != new_len)
|
|
goto out;
|
|
ret = addr;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Ok, we need to grow..
|
|
*/
|
|
vma = vma_to_resize(addr, old_len, new_len, &charged);
|
|
if (IS_ERR(vma)) {
|
|
ret = PTR_ERR(vma);
|
|
goto out;
|
|
}
|
|
|
|
/* old_len exactly to the end of the area..
|
|
*/
|
|
if (old_len == vma->vm_end - addr) {
|
|
/* can we just expand the current mapping? */
|
|
if (vma_expandable(vma, new_len - old_len)) {
|
|
int pages = (new_len - old_len) >> PAGE_SHIFT;
|
|
|
|
if (vma_adjust(vma, vma->vm_start, addr + new_len,
|
|
vma->vm_pgoff, NULL)) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
vm_stat_account(mm, vma->vm_flags, pages);
|
|
if (vma->vm_flags & VM_LOCKED) {
|
|
mm->locked_vm += pages;
|
|
locked = true;
|
|
new_addr = addr;
|
|
}
|
|
ret = addr;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We weren't able to just expand or shrink the area,
|
|
* we need to create a new one and move it..
|
|
*/
|
|
ret = -ENOMEM;
|
|
if (flags & MREMAP_MAYMOVE) {
|
|
unsigned long map_flags = 0;
|
|
if (vma->vm_flags & VM_MAYSHARE)
|
|
map_flags |= MAP_SHARED;
|
|
|
|
new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
|
|
vma->vm_pgoff +
|
|
((addr - vma->vm_start) >> PAGE_SHIFT),
|
|
map_flags);
|
|
if (offset_in_page(new_addr)) {
|
|
ret = new_addr;
|
|
goto out;
|
|
}
|
|
|
|
ret = move_vma(vma, addr, old_len, new_len, new_addr,
|
|
&locked, &uf, &uf_unmap);
|
|
}
|
|
out:
|
|
if (offset_in_page(ret)) {
|
|
vm_unacct_memory(charged);
|
|
locked = 0;
|
|
}
|
|
up_write(¤t->mm->mmap_sem);
|
|
if (locked && new_len > old_len)
|
|
mm_populate(new_addr + old_len, new_len - old_len);
|
|
userfaultfd_unmap_complete(mm, &uf_unmap_early);
|
|
mremap_userfaultfd_complete(&uf, addr, new_addr, old_len);
|
|
userfaultfd_unmap_complete(mm, &uf_unmap);
|
|
return ret;
|
|
}
|