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[Qemu-devel] [PATCH 08/21] userfaultfd: teach vma_merge to merge across
From: |
Andrea Arcangeli |
Subject: |
[Qemu-devel] [PATCH 08/21] userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx |
Date: |
Thu, 5 Mar 2015 18:17:51 +0100 |
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 <address@hidden>
---
include/linux/mm.h | 2 +-
mm/madvise.c | 3 ++-
mm/mempolicy.c | 4 ++--
mm/mlock.c | 3 ++-
mm/mmap.c | 39 +++++++++++++++++++++++++++------------
mm/mprotect.c | 3 ++-
6 files changed, 36 insertions(+), 18 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 762ef9d..26cef61 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1879,7 +1879,7 @@ 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 d551475..10f62b7 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -102,7 +102,8 @@ 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 4721046..e1a2e9b 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 73cf098..9725abe 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -566,7 +566,8 @@ 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 da9990a..135c2fa 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -41,6 +41,7 @@
#include <linux/notifier.h>
#include <linux/memory.h>
#include <linux/printk.h>
+#include <linux/userfaultfd_k.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -921,7 +922,8 @@ 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
@@ -937,6 +939,8 @@ 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;
}
@@ -967,9 +971,11 @@ 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;
@@ -986,9 +992,11 @@ 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);
@@ -1031,7 +1039,8 @@ 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;
@@ -1058,14 +1067,17 @@ 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 */
@@ -1086,7 +1098,8 @@ 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);
@@ -1573,7 +1586,8 @@ munmap_back:
/*
* 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;
@@ -2760,7 +2774,7 @@ 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;
@@ -2916,7 +2930,8 @@ 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 4472781..c98a074 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -287,7 +287,8 @@ 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;
- [Qemu-devel] [PATCH 00/21] RFC: userfaultfd v3, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 02/21] userfaultfd: linux/Documentation/vm/userfaultfd.txt, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 06/21] userfaultfd: add VM_UFFD_MISSING and VM_UFFD_WP, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 16/21] userfaultfd: remap_pages: rmap preparation, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 17/21] userfaultfd: remap_pages: swp_entry_swapcount() preparation, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 12/21] userfaultfd: activate syscall, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 11/21] userfaultfd: buildsystem activation, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 08/21] userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx,
Andrea Arcangeli <=
- [Qemu-devel] [PATCH 01/21] userfaultfd: waitqueue: add nr wake parameter to __wake_up_locked_key, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 13/21] userfaultfd: UFFDIO_COPY|UFFDIO_ZEROPAGE uAPI, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 15/21] userfaultfd: UFFDIO_COPY and UFFDIO_ZEROPAGE, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 20/21] userfaultfd: UFFDIO_REMAP, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 07/21] userfaultfd: call handle_userfault() for userfaultfd_missing() faults, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 10/21] userfaultfd: add new syscall to provide memory externalization, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 21/21] userfaultfd: add userfaultfd_wp mm helpers, Andrea Arcangeli, 2015/03/05
- [Qemu-devel] [PATCH 19/21] userfaultfd: remap_pages: UFFDIO_REMAP preparation, Andrea Arcangeli, 2015/03/05