diff options
| -rw-r--r-- | kernel/events/uprobes.c | 2 | ||||
| -rw-r--r-- | mm/filemap.c | 2 | ||||
| -rw-r--r-- | mm/mmap.c | 250 | ||||
| -rw-r--r-- | mm/rmap.c | 15 |
4 files changed, 107 insertions, 162 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 1a3904e0179c..59887c69d54c 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1351,7 +1351,7 @@ static int delayed_ref_ctr_inc(struct vm_area_struct *vma) } /* - * Called from mmap_region/vma_adjust with mm->mmap_lock acquired. + * Called from mmap_region/vma_merge with mm->mmap_lock acquired. * * Currently we ignore all errors and always return 0, the callers * can't handle the failure anyway. diff --git a/mm/filemap.c b/mm/filemap.c index c915ded191f0..992554c18f1f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -97,7 +97,7 @@ * ->i_pages lock (__sync_single_inode) * * ->i_mmap_rwsem - * ->anon_vma.lock (vma_adjust) + * ->anon_vma.lock (vma_merge) * * ->anon_vma.lock * ->page_table_lock or pte_lock (anon_vma_prepare and various) diff --git a/mm/mmap.c b/mm/mmap.c index 604ba8293a95..8ce4cee42dce 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -741,133 +741,6 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, } /* - * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that - * is already present in an i_mmap tree without adjusting the tree. - * The following helper function should be used when such adjustments - * are necessary. The "insert" vma (if any) is to be inserted - * before we drop the necessary locks. - */ -int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma, - unsigned long start, unsigned long end, pgoff_t pgoff, - struct vm_area_struct *expand) -{ - struct mm_struct *mm = vma->vm_mm; - struct vm_area_struct *remove2 = NULL; - struct vm_area_struct *remove = NULL; - struct vm_area_struct *next = find_vma(mm, vma->vm_end); - struct vm_area_struct *orig_vma = vma; - struct file *file = vma->vm_file; - bool vma_changed = false; - long adjust_next = 0; - struct vma_prepare vma_prep; - - if (next) { - int error = 0; - - if (end >= next->vm_end) { - /* - * vma expands, overlapping all the next, and - * perhaps the one after too (mprotect case 6). - * The only other cases that gets here are - * case 1, case 7 and case 8. - */ - if (next == expand) { - /* - * The only case where we don't expand "vma" - * and we expand "next" instead is case 8. - */ - VM_WARN_ON(end != next->vm_end); - /* - * we're removing "vma" and that to do so we - * swapped "vma" and "next". - */ - VM_WARN_ON(file != next->vm_file); - swap(vma, next); - remove = next; - } else { - VM_WARN_ON(expand != vma); - /* - * case 1, 6, 7, remove next. - * case 6 also removes the one beyond next - */ - remove = next; - if (end > next->vm_end) - remove2 = find_vma(mm, next->vm_end); - - VM_WARN_ON(remove2 != NULL && - end != remove2->vm_end); - } - - /* - * If next doesn't have anon_vma, import from vma after - * next, if the vma overlaps with it. - */ - if (remove != NULL && !next->anon_vma) - error = dup_anon_vma(vma, remove2); - else - error = dup_anon_vma(vma, remove); - - } else if (end > next->vm_start) { - /* - * vma expands, overlapping part of the next: - * mprotect case 5 shifting the boundary up. - */ - adjust_next = (end - next->vm_start); - VM_WARN_ON(expand != vma); - error = dup_anon_vma(vma, next); - } else if (end < vma->vm_end) { - /* - * vma shrinks, and !insert tells it's not - * split_vma inserting another: so it must be - * mprotect case 4 shifting the boundary down. - */ - adjust_next = -(vma->vm_end - end); - VM_WARN_ON(expand != next); - error = dup_anon_vma(next, vma); - } - if (error) - return error; - } - - if (vma_iter_prealloc(vmi)) - return -ENOMEM; - - vma_adjust_trans_huge(orig_vma, start, end, adjust_next); - - init_multi_vma_prep(&vma_prep, vma, adjust_next ? next : NULL, remove, - remove2); - VM_WARN_ON(vma_prep.anon_vma && adjust_next && next->anon_vma && - vma_prep.anon_vma != next->anon_vma); - - vma_prepare(&vma_prep); - - if (start < vma->vm_start || end > vma->vm_end) - vma_changed = true; - - vma->vm_start = start; - vma->vm_end = end; - vma->vm_pgoff = pgoff; - - if (vma_changed) - vma_iter_store(vmi, vma); - - if (adjust_next) { - next->vm_start += adjust_next; - next->vm_pgoff += adjust_next >> PAGE_SHIFT; - if (adjust_next < 0) { - WARN_ON_ONCE(vma_changed); - vma_iter_store(vmi, next); - } - } - - vma_complete(&vma_prep, vmi, mm); - vma_iter_free(vmi); - validate_mm(mm); - - return 0; -} - -/* * If the vma has a ->close operation then the driver probably needs to release * per-vma resources, so we don't attempt to merge those. */ @@ -993,7 +866,7 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, * It is important for case 8 that the vma NNNN overlapping the * region AAAA is never going to extended over XXXX. Instead XXXX must * be extended in region AAAA and NNNN must be removed. This way in - * all cases where vma_merge succeeds, the moment vma_adjust drops the + * all cases where vma_merge succeeds, the moment vma_merge drops the * rmap_locks, the properties of the merged vma will be already * correct for the whole merged range. Some of those properties like * vm_page_prot/vm_flags may be accessed by rmap_walks and they must @@ -1003,6 +876,12 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, * or other rmap walkers (if working on addresses beyond the "end" * parameter) may establish ptes with the wrong permissions of NNNN * instead of the right permissions of XXXX. + * + * In the code below: + * PPPP is represented by *prev + * NNNN is represented by *mid (and possibly equal to *next) + * XXXX is represented by *next or not represented at all. + * AAAA is not represented - it will be merged or the function will return NULL */ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, struct vm_area_struct *prev, unsigned long addr, @@ -1013,11 +892,19 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, struct anon_vma_name *anon_name) { pgoff_t pglen = (end - addr) >> PAGE_SHIFT; + pgoff_t vma_pgoff; struct vm_area_struct *mid, *next, *res = NULL; + struct vm_area_struct *vma, *adjust, *remove, *remove2; int err = -1; bool merge_prev = false; bool merge_next = false; + bool vma_expanded = false; + struct vma_prepare vp; + unsigned long vma_end = end; + long adj_next = 0; + unsigned long vma_start = addr; + validate_mm(mm); /* * We later require that vma->vm_flags == vm_flags, * so this tests vma->vm_flags & VM_SPECIAL, too. @@ -1035,13 +922,17 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, VM_WARN_ON(mid && end > mid->vm_end); VM_WARN_ON(addr >= end); - /* Can we merge the predecessor? */ - if (prev && prev->vm_end == addr && - mpol_equal(vma_policy(prev), policy) && - can_vma_merge_after(prev, vm_flags, - anon_vma, file, pgoff, - vm_userfaultfd_ctx, anon_name)) { - merge_prev = true; + if (prev) { + res = prev; + vma = prev; + vma_start = prev->vm_start; + vma_pgoff = prev->vm_pgoff; + /* Can we merge the predecessor? */ + if (prev->vm_end == addr && mpol_equal(vma_policy(prev), policy) + && can_vma_merge_after(prev, vm_flags, anon_vma, file, + pgoff, vm_userfaultfd_ctx, anon_name)) { + merge_prev = true; + } } /* Can we merge the successor? */ if (next && end == next->vm_start && @@ -1051,32 +942,85 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, vm_userfaultfd_ctx, anon_name)) { merge_next = true; } + + remove = remove2 = adjust = NULL; /* Can we merge both the predecessor and the successor? */ if (merge_prev && merge_next && - is_mergeable_anon_vma(prev->anon_vma, - next->anon_vma, NULL)) { /* cases 1, 6 */ - err = __vma_adjust(vmi, prev, prev->vm_start, - next->vm_end, prev->vm_pgoff, prev); - res = prev; - } else if (merge_prev) { /* cases 2, 5, 7 */ - err = __vma_adjust(vmi, prev, prev->vm_start, - end, prev->vm_pgoff, prev); - res = prev; + is_mergeable_anon_vma(prev->anon_vma, next->anon_vma, NULL)) { + remove = mid; /* case 1 */ + vma_end = next->vm_end; + err = dup_anon_vma(res, remove); + if (mid != next) { /* case 6 */ + remove2 = next; + if (!remove->anon_vma) + err = dup_anon_vma(res, remove2); + } + } else if (merge_prev) { + err = 0; /* case 2 */ + if (mid && end > mid->vm_start) { + err = dup_anon_vma(res, mid); + if (end == mid->vm_end) { /* case 7 */ + remove = mid; + } else { /* case 5 */ + adjust = mid; + adj_next = (end - mid->vm_start); + } + } } else if (merge_next) { - if (prev && addr < prev->vm_end) /* case 4 */ - err = __vma_adjust(vmi, prev, prev->vm_start, - addr, prev->vm_pgoff, next); - else /* cases 3, 8 */ - err = __vma_adjust(vmi, mid, addr, next->vm_end, - next->vm_pgoff - pglen, next); res = next; + if (prev && addr < prev->vm_end) { /* case 4 */ + vma_end = addr; + adjust = mid; + adj_next = -(vma->vm_end - addr); + err = dup_anon_vma(res, adjust); + } else { + vma = next; /* case 3 */ + vma_start = addr; + vma_end = next->vm_end; + vma_pgoff = mid->vm_pgoff; + err = 0; + if (mid != next) { /* case 8 */ + remove = mid; + err = dup_anon_vma(res, remove); + } + } } - /* - * Cannot merge with predecessor or successor or error in __vma_adjust? - */ + /* Cannot merge or error in anon_vma clone */ if (err) return NULL; + + if (vma_iter_prealloc(vmi)) + return NULL; + + vma_adjust_trans_huge(vma, vma_start, vma_end, adj_next); + init_multi_vma_prep(&vp, vma, adjust, remove, remove2); + VM_WARN_ON(vp.anon_vma && adjust && adjust->anon_vma && + vp.anon_vma != adjust->anon_vma); + + vma_prepare(&vp); + if (vma_start < vma->vm_start || vma_end > vma->vm_end) + vma_expanded = true; + + vma->vm_start = vma_start; + vma->vm_end = vma_end; + vma->vm_pgoff = vma_pgoff; + + if (vma_expanded) + vma_iter_store(vmi, vma); + + if (adj_next) { + adjust->vm_start += adj_next; + adjust->vm_pgoff += adj_next >> PAGE_SHIFT; + if (adj_next < 0) { + WARN_ON(vma_expanded); + vma_iter_store(vmi, next); + } + } + + vma_complete(&vp, vmi, mm); + vma_iter_free(vmi); + validate_mm(mm); khugepaged_enter_vma(res, vm_flags); if (res) diff --git a/mm/rmap.c b/mm/rmap.c index 43760d622040..86fccc2b9fc9 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -262,11 +262,12 @@ static inline void unlock_anon_vma_root(struct anon_vma *root) * Attach the anon_vmas from src to dst. * Returns 0 on success, -ENOMEM on failure. * - * anon_vma_clone() is called by __vma_adjust(), __split_vma(), copy_vma() and - * anon_vma_fork(). The first three want an exact copy of src, while the last - * one, anon_vma_fork(), may try to reuse an existing anon_vma to prevent - * endless growth of anon_vma. Since dst->anon_vma is set to NULL before call, - * we can identify this case by checking (!dst->anon_vma && src->anon_vma). + * anon_vma_clone() is called by vma_expand(), vma_merge(), __split_vma(), + * copy_vma() and anon_vma_fork(). The first four want an exact copy of src, + * while the last one, anon_vma_fork(), may try to reuse an existing anon_vma to + * prevent endless growth of anon_vma. Since dst->anon_vma is set to NULL before + * call, we can identify this case by checking (!dst->anon_vma && + * src->anon_vma). * * If (!dst->anon_vma && src->anon_vma) is true, this function tries to find * and reuse existing anon_vma which has no vmas and only one child anon_vma. @@ -1253,7 +1254,7 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma, __lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr); if (likely(!folio_test_ksm(folio))) { - /* address might be in next vma when migration races vma_adjust */ + /* address might be in next vma when migration races vma_merge */ if (first) __page_set_anon_rmap(folio, page, vma, address, !!(flags & RMAP_EXCLUSIVE)); @@ -2524,7 +2525,7 @@ void hugepage_add_anon_rmap(struct page *page, struct vm_area_struct *vma, BUG_ON(!folio_test_locked(folio)); BUG_ON(!anon_vma); - /* address might be in next vma when migration races vma_adjust */ + /* address might be in next vma when migration races vma_merge */ first = atomic_inc_and_test(&folio->_entire_mapcount); VM_BUG_ON_PAGE(!first && (flags & RMAP_EXCLUSIVE), page); VM_BUG_ON_PAGE(!first && PageAnonExclusive(page), page); |