From 19a809afe2fe089317226bbe5c5a1ce7f53dcdca Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Fri, 4 Sep 2015 15:46:24 -0700 Subject: [PATCH] userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli Acked-by: Pavel Emelyanov Cc: Sanidhya Kashyap Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" Cc: Andres Lagar-Cavilla Cc: Dave Hansen Cc: Paolo Bonzini Cc: Rik van Riel Cc: Mel Gorman Cc: Andy Lutomirski Cc: Hugh Dickins Cc: Peter Feiner Cc: "Dr. David Alan Gilbert" Cc: Johannes Weiner Cc: "Huangpeng (Peter)" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 2 +- mm/madvise.c | 3 ++- mm/mempolicy.c | 4 ++-- mm/mlock.c | 3 ++- mm/mmap.c | 40 +++++++++++++++++++++++++++------------- mm/mprotect.c | 3 ++- 6 files changed, 36 insertions(+), 19 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0f7cd30039ea..77a9d609523e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1835,7 +1835,7 @@ extern int vma_adjust(struct vm_area_struct *vma, unsigned long start, extern struct vm_area_struct *vma_merge(struct mm_struct *, struct vm_area_struct *prev, unsigned long addr, unsigned long end, unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t, - struct mempolicy *); + struct mempolicy *, struct vm_userfaultfd_ctx); extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *); extern int split_vma(struct mm_struct *, struct vm_area_struct *, unsigned long addr, int new_below); diff --git a/mm/madvise.c b/mm/madvise.c index 64bb8a22110c..911357973905 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -103,7 +103,8 @@ static long madvise_behavior(struct vm_area_struct *vma, pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); *prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma, - vma->vm_file, pgoff, vma_policy(vma)); + vma->vm_file, pgoff, vma_policy(vma), + vma->vm_userfaultfd_ctx); if (*prev) { vma = *prev; goto success; diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 99d4c1d0b858..a7f1e0d1d6b8 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -722,8 +722,8 @@ static int mbind_range(struct mm_struct *mm, unsigned long start, pgoff = vma->vm_pgoff + ((vmstart - vma->vm_start) >> PAGE_SHIFT); prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags, - vma->anon_vma, vma->vm_file, pgoff, - new_pol); + vma->anon_vma, vma->vm_file, pgoff, + new_pol, vma->vm_userfaultfd_ctx); if (prev) { vma = prev; next = vma->vm_next; diff --git a/mm/mlock.c b/mm/mlock.c index 6fd2cf15e868..25936680064f 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -510,7 +510,8 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, - vma->vm_file, pgoff, vma_policy(vma)); + vma->vm_file, pgoff, vma_policy(vma), + vma->vm_userfaultfd_ctx); if (*prev) { vma = *prev; goto success; diff --git a/mm/mmap.c b/mm/mmap.c index f126923ce683..82db4fc0a9d3 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include @@ -919,7 +920,8 @@ again: remove_next = 1 + (end > next->vm_end); * per-vma resources, so we don't attempt to merge those. */ static inline int is_mergeable_vma(struct vm_area_struct *vma, - struct file *file, unsigned long vm_flags) + struct file *file, unsigned long vm_flags, + struct vm_userfaultfd_ctx vm_userfaultfd_ctx) { /* * VM_SOFTDIRTY should not prevent from VMA merging, if we @@ -935,6 +937,8 @@ static inline int is_mergeable_vma(struct vm_area_struct *vma, return 0; if (vma->vm_ops && vma->vm_ops->close) return 0; + if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) + return 0; return 1; } @@ -965,9 +969,11 @@ static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, */ static int can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, - struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) + struct anon_vma *anon_vma, struct file *file, + pgoff_t vm_pgoff, + struct vm_userfaultfd_ctx vm_userfaultfd_ctx) { - if (is_mergeable_vma(vma, file, vm_flags) && + if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) && is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { if (vma->vm_pgoff == vm_pgoff) return 1; @@ -984,9 +990,11 @@ can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, */ static int can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, - struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) + struct anon_vma *anon_vma, struct file *file, + pgoff_t vm_pgoff, + struct vm_userfaultfd_ctx vm_userfaultfd_ctx) { - if (is_mergeable_vma(vma, file, vm_flags) && + if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) && is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { pgoff_t vm_pglen; vm_pglen = vma_pages(vma); @@ -1029,7 +1037,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm, struct vm_area_struct *prev, unsigned long addr, unsigned long end, unsigned long vm_flags, struct anon_vma *anon_vma, struct file *file, - pgoff_t pgoff, struct mempolicy *policy) + pgoff_t pgoff, struct mempolicy *policy, + struct vm_userfaultfd_ctx vm_userfaultfd_ctx) { pgoff_t pglen = (end - addr) >> PAGE_SHIFT; struct vm_area_struct *area, *next; @@ -1056,14 +1065,17 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm, if (prev && prev->vm_end == addr && mpol_equal(vma_policy(prev), policy) && can_vma_merge_after(prev, vm_flags, - anon_vma, file, pgoff)) { + anon_vma, file, pgoff, + vm_userfaultfd_ctx)) { /* * OK, it can. Can we now merge in the successor as well? */ if (next && end == next->vm_start && mpol_equal(policy, vma_policy(next)) && can_vma_merge_before(next, vm_flags, - anon_vma, file, pgoff+pglen) && + anon_vma, file, + pgoff+pglen, + vm_userfaultfd_ctx) && is_mergeable_anon_vma(prev->anon_vma, next->anon_vma, NULL)) { /* cases 1, 6 */ @@ -1084,7 +1096,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm, if (next && end == next->vm_start && mpol_equal(policy, vma_policy(next)) && can_vma_merge_before(next, vm_flags, - anon_vma, file, pgoff+pglen)) { + anon_vma, file, pgoff+pglen, + vm_userfaultfd_ctx)) { if (prev && addr < prev->vm_end) /* case 4 */ err = vma_adjust(prev, prev->vm_start, addr, prev->vm_pgoff, NULL); @@ -1570,8 +1583,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* * Can we just expand an old mapping? */ - vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, - NULL); + vma = vma_merge(mm, prev, addr, addr + len, vm_flags, + NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX); if (vma) goto out; @@ -2757,7 +2770,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) /* Can we just expand an old private anonymous mapping? */ vma = vma_merge(mm, prev, addr, addr + len, flags, - NULL, NULL, pgoff, NULL); + NULL, NULL, pgoff, NULL, NULL_VM_UFFD_CTX); if (vma) goto out; @@ -2913,7 +2926,8 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) return NULL; /* should never get here */ new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); + vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), + vma->vm_userfaultfd_ctx); if (new_vma) { /* * Source vma may have been merged into new_vma diff --git a/mm/mprotect.c b/mm/mprotect.c index e7d6f1171ecb..ef5be8eaab00 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -292,7 +292,8 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, */ pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); *pprev = vma_merge(mm, *pprev, start, end, newflags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); + vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), + vma->vm_userfaultfd_ctx); if (*pprev) { vma = *pprev; goto success;