#include "internal.h"
static __always_inline
-struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm,
- unsigned long dst_start,
- unsigned long len)
+bool validate_dst_vma(struct vm_area_struct *dst_vma, unsigned long dst_end)
{
- /*
- * Make sure that the dst range is both valid and fully within a
- * single existing vma.
- */
- struct vm_area_struct *dst_vma;
-
- dst_vma = find_vma(dst_mm, dst_start);
- if (!range_in_vma(dst_vma, dst_start, dst_start + len))
- return NULL;
+ /* Make sure that the dst range is fully within dst_vma. */
+ if (dst_end > dst_vma->vm_end)
+ return false;
/*
* Check the vma is registered in uffd, this is required to
* time.
*/
if (!dst_vma->vm_userfaultfd_ctx.ctx)
- return NULL;
+ return false;
+
+ return true;
+}
+
+static __always_inline
+struct vm_area_struct *find_vma_and_prepare_anon(struct mm_struct *mm,
+ unsigned long addr)
+{
+ struct vm_area_struct *vma;
+
+ mmap_assert_locked(mm);
+ vma = vma_lookup(mm, addr);
+ if (!vma)
+ vma = ERR_PTR(-ENOENT);
+ else if (!(vma->vm_flags & VM_SHARED) &&
+ unlikely(anon_vma_prepare(vma)))
+ vma = ERR_PTR(-ENOMEM);
+
+ return vma;
+}
+
+#ifdef CONFIG_PER_VMA_LOCK
+/*
+ * lock_vma() - Lookup and lock vma corresponding to @address.
+ * @mm: mm to search vma in.
+ * @address: address that the vma should contain.
+ *
+ * Should be called without holding mmap_lock. vma should be unlocked after use
+ * with unlock_vma().
+ *
+ * Return: A locked vma containing @address, -ENOENT if no vma is found, or
+ * -ENOMEM if anon_vma couldn't be allocated.
+ */
+static struct vm_area_struct *lock_vma(struct mm_struct *mm,
+ unsigned long address)
+{
+ struct vm_area_struct *vma;
+ vma = lock_vma_under_rcu(mm, address);
+ if (vma) {
+ /*
+ * lock_vma_under_rcu() only checks anon_vma for private
+ * anonymous mappings. But we need to ensure it is assigned in
+ * private file-backed vmas as well.
+ */
+ if (!(vma->vm_flags & VM_SHARED) && unlikely(!vma->anon_vma))
+ vma_end_read(vma);
+ else
+ return vma;
+ }
+
+ mmap_read_lock(mm);
+ vma = find_vma_and_prepare_anon(mm, address);
+ if (!IS_ERR(vma)) {
+ /*
+ * We cannot use vma_start_read() as it may fail due to
+ * false locked (see comment in vma_start_read()). We
+ * can avoid that by directly locking vm_lock under
+ * mmap_lock, which guarantees that nobody can lock the
+ * vma for write (vma_start_write()) under us.
+ */
+ down_read(&vma->vm_lock->lock);
+ }
+
+ mmap_read_unlock(mm);
+ return vma;
+}
+
+static struct vm_area_struct *uffd_mfill_lock(struct mm_struct *dst_mm,
+ unsigned long dst_start,
+ unsigned long len)
+{
+ struct vm_area_struct *dst_vma;
+
+ dst_vma = lock_vma(dst_mm, dst_start);
+ if (IS_ERR(dst_vma) || validate_dst_vma(dst_vma, dst_start + len))
+ return dst_vma;
+
+ vma_end_read(dst_vma);
+ return ERR_PTR(-ENOENT);
+}
+
+static void uffd_mfill_unlock(struct vm_area_struct *vma)
+{
+ vma_end_read(vma);
+}
+
+#else
+
+static struct vm_area_struct *uffd_mfill_lock(struct mm_struct *dst_mm,
+ unsigned long dst_start,
+ unsigned long len)
+{
+ struct vm_area_struct *dst_vma;
+
+ mmap_read_lock(dst_mm);
+ dst_vma = find_vma_and_prepare_anon(dst_mm, dst_start);
+ if (IS_ERR(dst_vma))
+ goto out_unlock;
+
+ if (validate_dst_vma(dst_vma, dst_start + len))
+ return dst_vma;
+
+ dst_vma = ERR_PTR(-ENOENT);
+out_unlock:
+ mmap_read_unlock(dst_mm);
return dst_vma;
}
+static void uffd_mfill_unlock(struct vm_area_struct *vma)
+{
+ mmap_read_unlock(vma->vm_mm);
+}
+#endif
+
/* Check if dst_addr is outside of file's size. Must be called with ptl held. */
static bool mfill_file_over_size(struct vm_area_struct *dst_vma,
unsigned long dst_addr)
* Must happen after rmap, as mm_counter() checks mapping (via
* PageAnon()), which is set by __page_set_anon_rmap().
*/
- inc_mm_counter(dst_mm, mm_counter(page));
+ inc_mm_counter(dst_mm, mm_counter(folio));
set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
#ifdef CONFIG_HUGETLB_PAGE
/*
* mfill_atomic processing for HUGETLB vmas. Note that this routine is
- * called with mmap_lock held, it will release mmap_lock before returning.
+ * called with either vma-lock or mmap_lock held, it will release the lock
+ * before returning.
*/
static __always_inline ssize_t mfill_atomic_hugetlb(
+ struct userfaultfd_ctx *ctx,
struct vm_area_struct *dst_vma,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- atomic_t *mmap_changing,
uffd_flags_t flags)
{
struct mm_struct *dst_mm = dst_vma->vm_mm;
- int vm_shared = dst_vma->vm_flags & VM_SHARED;
ssize_t err;
pte_t *dst_pte;
unsigned long src_addr, dst_addr;
* feature is not supported.
*/
if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE)) {
- mmap_read_unlock(dst_mm);
+ up_read(&ctx->map_changing_lock);
+ uffd_mfill_unlock(dst_vma);
return -EINVAL;
}
* retry, dst_vma will be set to NULL and we must lookup again.
*/
if (!dst_vma) {
+ dst_vma = uffd_mfill_lock(dst_mm, dst_start, len);
+ if (IS_ERR(dst_vma)) {
+ err = PTR_ERR(dst_vma);
+ goto out;
+ }
+
err = -ENOENT;
- dst_vma = find_dst_vma(dst_mm, dst_start, len);
- if (!dst_vma || !is_vm_hugetlb_page(dst_vma))
- goto out_unlock;
+ if (!is_vm_hugetlb_page(dst_vma))
+ goto out_unlock_vma;
err = -EINVAL;
if (vma_hpagesize != vma_kernel_pagesize(dst_vma))
- goto out_unlock;
-
- vm_shared = dst_vma->vm_flags & VM_SHARED;
- }
+ goto out_unlock_vma;
- /*
- * If not shared, ensure the dst_vma has a anon_vma.
- */
- err = -ENOMEM;
- if (!vm_shared) {
- if (unlikely(anon_vma_prepare(dst_vma)))
+ /*
+ * If memory mappings are changing because of non-cooperative
+ * operation (e.g. mremap) running in parallel, bail out and
+ * request the user to retry later
+ */
+ down_read(&ctx->map_changing_lock);
+ err = -EAGAIN;
+ if (atomic_read(&ctx->mmap_changing))
goto out_unlock;
}
cond_resched();
if (unlikely(err == -ENOENT)) {
- mmap_read_unlock(dst_mm);
+ up_read(&ctx->map_changing_lock);
+ uffd_mfill_unlock(dst_vma);
BUG_ON(!folio);
err = copy_folio_from_user(folio,
err = -EFAULT;
goto out;
}
- mmap_read_lock(dst_mm);
- /*
- * If memory mappings are changing because of non-cooperative
- * operation (e.g. mremap) running in parallel, bail out and
- * request the user to retry later
- */
- if (mmap_changing && atomic_read(mmap_changing)) {
- err = -EAGAIN;
- break;
- }
dst_vma = NULL;
goto retry;
}
out_unlock:
- mmap_read_unlock(dst_mm);
+ up_read(&ctx->map_changing_lock);
+out_unlock_vma:
+ uffd_mfill_unlock(dst_vma);
out:
if (folio)
folio_put(folio);
}
#else /* !CONFIG_HUGETLB_PAGE */
/* fail at build time if gcc attempts to use this */
-extern ssize_t mfill_atomic_hugetlb(struct vm_area_struct *dst_vma,
+extern ssize_t mfill_atomic_hugetlb(struct userfaultfd_ctx *ctx,
+ struct vm_area_struct *dst_vma,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- atomic_t *mmap_changing,
uffd_flags_t flags);
#endif /* CONFIG_HUGETLB_PAGE */
return err;
}
-static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
+static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- atomic_t *mmap_changing,
uffd_flags_t flags)
{
+ struct mm_struct *dst_mm = ctx->mm;
struct vm_area_struct *dst_vma;
ssize_t err;
pmd_t *dst_pmd;
copied = 0;
folio = NULL;
retry:
- mmap_read_lock(dst_mm);
+ /*
+ * Make sure the vma is not shared, that the dst range is
+ * both valid and fully within a single existing vma.
+ */
+ dst_vma = uffd_mfill_lock(dst_mm, dst_start, len);
+ if (IS_ERR(dst_vma)) {
+ err = PTR_ERR(dst_vma);
+ goto out;
+ }
/*
* If memory mappings are changing because of non-cooperative
* operation (e.g. mremap) running in parallel, bail out and
* request the user to retry later
*/
+ down_read(&ctx->map_changing_lock);
err = -EAGAIN;
- if (mmap_changing && atomic_read(mmap_changing))
- goto out_unlock;
-
- /*
- * Make sure the vma is not shared, that the dst range is
- * both valid and fully within a single existing vma.
- */
- err = -ENOENT;
- dst_vma = find_dst_vma(dst_mm, dst_start, len);
- if (!dst_vma)
+ if (atomic_read(&ctx->mmap_changing))
goto out_unlock;
err = -EINVAL;
* If this is a HUGETLB vma, pass off to appropriate routine
*/
if (is_vm_hugetlb_page(dst_vma))
- return mfill_atomic_hugetlb(dst_vma, dst_start, src_start,
- len, mmap_changing, flags);
+ return mfill_atomic_hugetlb(ctx, dst_vma, dst_start,
+ src_start, len, flags);
if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma))
goto out_unlock;
uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE))
goto out_unlock;
- /*
- * Ensure the dst_vma has a anon_vma or this page
- * would get a NULL anon_vma when moved in the
- * dst_vma.
- */
- err = -ENOMEM;
- if (!(dst_vma->vm_flags & VM_SHARED) &&
- unlikely(anon_vma_prepare(dst_vma)))
- goto out_unlock;
-
while (src_addr < src_start + len) {
pmd_t dst_pmdval;
if (unlikely(err == -ENOENT)) {
void *kaddr;
- mmap_read_unlock(dst_mm);
+ up_read(&ctx->map_changing_lock);
+ uffd_mfill_unlock(dst_vma);
BUG_ON(!folio);
kaddr = kmap_local_folio(folio, 0);
}
out_unlock:
- mmap_read_unlock(dst_mm);
+ up_read(&ctx->map_changing_lock);
+ uffd_mfill_unlock(dst_vma);
out:
if (folio)
folio_put(folio);
return copied ? copied : err;
}
-ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long dst_start,
+ssize_t mfill_atomic_copy(struct userfaultfd_ctx *ctx, unsigned long dst_start,
unsigned long src_start, unsigned long len,
- atomic_t *mmap_changing, uffd_flags_t flags)
+ uffd_flags_t flags)
{
- return mfill_atomic(dst_mm, dst_start, src_start, len, mmap_changing,
+ return mfill_atomic(ctx, dst_start, src_start, len,
uffd_flags_set_mode(flags, MFILL_ATOMIC_COPY));
}
-ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, unsigned long start,
- unsigned long len, atomic_t *mmap_changing)
+ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
+ unsigned long start,
+ unsigned long len)
{
- return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
+ return mfill_atomic(ctx, start, 0, len,
uffd_flags_set_mode(0, MFILL_ATOMIC_ZEROPAGE));
}
-ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long start,
- unsigned long len, atomic_t *mmap_changing,
- uffd_flags_t flags)
+ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long start,
+ unsigned long len, uffd_flags_t flags)
{
- return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
+
+ /*
+ * A caller might reasonably assume that UFFDIO_CONTINUE contains an
+ * smp_wmb() to ensure that any writes to the about-to-be-mapped page by
+ * the thread doing the UFFDIO_CONTINUE are guaranteed to be visible to
+ * subsequent loads from the page through the newly mapped address range.
+ */
+ smp_wmb();
+
+ return mfill_atomic(ctx, start, 0, len,
uffd_flags_set_mode(flags, MFILL_ATOMIC_CONTINUE));
}
-ssize_t mfill_atomic_poison(struct mm_struct *dst_mm, unsigned long start,
- unsigned long len, atomic_t *mmap_changing,
- uffd_flags_t flags)
+ssize_t mfill_atomic_poison(struct userfaultfd_ctx *ctx, unsigned long start,
+ unsigned long len, uffd_flags_t flags)
{
- return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
+ return mfill_atomic(ctx, start, 0, len,
uffd_flags_set_mode(flags, MFILL_ATOMIC_POISON));
}
return ret;
}
-int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
- unsigned long len, bool enable_wp,
- atomic_t *mmap_changing)
+int mwriteprotect_range(struct userfaultfd_ctx *ctx, unsigned long start,
+ unsigned long len, bool enable_wp)
{
+ struct mm_struct *dst_mm = ctx->mm;
unsigned long end = start + len;
unsigned long _start, _end;
struct vm_area_struct *dst_vma;
* operation (e.g. mremap) running in parallel, bail out and
* request the user to retry later
*/
+ down_read(&ctx->map_changing_lock);
err = -EAGAIN;
- if (mmap_changing && atomic_read(mmap_changing))
+ if (atomic_read(&ctx->mmap_changing))
goto out_unlock;
err = -ENOENT;
err = 0;
}
out_unlock:
+ up_read(&ctx->map_changing_lock);
mmap_read_unlock(dst_mm);
return err;
}
return 0;
}
+static int move_zeropage_pte(struct mm_struct *mm,
+ struct vm_area_struct *dst_vma,
+ struct vm_area_struct *src_vma,
+ unsigned long dst_addr, unsigned long src_addr,
+ pte_t *dst_pte, pte_t *src_pte,
+ pte_t orig_dst_pte, pte_t orig_src_pte,
+ spinlock_t *dst_ptl, spinlock_t *src_ptl)
+{
+ pte_t zero_pte;
+
+ double_pt_lock(dst_ptl, src_ptl);
+ if (!pte_same(ptep_get(src_pte), orig_src_pte) ||
+ !pte_same(ptep_get(dst_pte), orig_dst_pte)) {
+ double_pt_unlock(dst_ptl, src_ptl);
+ return -EAGAIN;
+ }
+
+ zero_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
+ dst_vma->vm_page_prot));
+ ptep_clear_flush(src_vma, src_addr, src_pte);
+ set_pte_at(mm, dst_addr, dst_pte, zero_pte);
+ double_pt_unlock(dst_ptl, src_ptl);
+
+ return 0;
+}
+
+
/*
* The mmap_lock for reading is held by the caller. Just move the page
* from src_pmd to dst_pmd if possible, and return true if succeeded
}
if (pte_present(orig_src_pte)) {
+ if (is_zero_pfn(pte_pfn(orig_src_pte))) {
+ err = move_zeropage_pte(mm, dst_vma, src_vma,
+ dst_addr, src_addr, dst_pte, src_pte,
+ orig_dst_pte, orig_src_pte,
+ dst_ptl, src_ptl);
+ goto out;
+ }
+
/*
* Pin and lock both source folio and anon_vma. Since we are in
* RCU read section, we can't block, so on contention have to
if (!vma_is_anonymous(src_vma) || !vma_is_anonymous(dst_vma))
return -EINVAL;
+ return 0;
+}
+
+static __always_inline
+int find_vmas_mm_locked(struct mm_struct *mm,
+ unsigned long dst_start,
+ unsigned long src_start,
+ struct vm_area_struct **dst_vmap,
+ struct vm_area_struct **src_vmap)
+{
+ struct vm_area_struct *vma;
+
+ mmap_assert_locked(mm);
+ vma = find_vma_and_prepare_anon(mm, dst_start);
+ if (IS_ERR(vma))
+ return PTR_ERR(vma);
+
+ *dst_vmap = vma;
+ /* Skip finding src_vma if src_start is in dst_vma */
+ if (src_start >= vma->vm_start && src_start < vma->vm_end)
+ goto out_success;
+
+ vma = vma_lookup(mm, src_start);
+ if (!vma)
+ return -ENOENT;
+out_success:
+ *src_vmap = vma;
+ return 0;
+}
+
+#ifdef CONFIG_PER_VMA_LOCK
+static int uffd_move_lock(struct mm_struct *mm,
+ unsigned long dst_start,
+ unsigned long src_start,
+ struct vm_area_struct **dst_vmap,
+ struct vm_area_struct **src_vmap)
+{
+ struct vm_area_struct *vma;
+ int err;
+
+ vma = lock_vma(mm, dst_start);
+ if (IS_ERR(vma))
+ return PTR_ERR(vma);
+
+ *dst_vmap = vma;
/*
- * Ensure the dst_vma has a anon_vma or this page
- * would get a NULL anon_vma when moved in the
- * dst_vma.
+ * Skip finding src_vma if src_start is in dst_vma. This also ensures
+ * that we don't lock the same vma twice.
*/
- if (unlikely(anon_vma_prepare(dst_vma)))
- return -ENOMEM;
+ if (src_start >= vma->vm_start && src_start < vma->vm_end) {
+ *src_vmap = vma;
+ return 0;
+ }
- return 0;
+ /*
+ * Using lock_vma() to get src_vma can lead to following deadlock:
+ *
+ * Thread1 Thread2
+ * ------- -------
+ * vma_start_read(dst_vma)
+ * mmap_write_lock(mm)
+ * vma_start_write(src_vma)
+ * vma_start_read(src_vma)
+ * mmap_read_lock(mm)
+ * vma_start_write(dst_vma)
+ */
+ *src_vmap = lock_vma_under_rcu(mm, src_start);
+ if (likely(*src_vmap))
+ return 0;
+
+ /* Undo any locking and retry in mmap_lock critical section */
+ vma_end_read(*dst_vmap);
+
+ mmap_read_lock(mm);
+ err = find_vmas_mm_locked(mm, dst_start, src_start, dst_vmap, src_vmap);
+ if (!err) {
+ /*
+ * See comment in lock_vma() as to why not using
+ * vma_start_read() here.
+ */
+ down_read(&(*dst_vmap)->vm_lock->lock);
+ if (*dst_vmap != *src_vmap)
+ down_read(&(*src_vmap)->vm_lock->lock);
+ }
+ mmap_read_unlock(mm);
+ return err;
+}
+
+static void uffd_move_unlock(struct vm_area_struct *dst_vma,
+ struct vm_area_struct *src_vma)
+{
+ vma_end_read(src_vma);
+ if (src_vma != dst_vma)
+ vma_end_read(dst_vma);
+}
+
+#else
+
+static int uffd_move_lock(struct mm_struct *mm,
+ unsigned long dst_start,
+ unsigned long src_start,
+ struct vm_area_struct **dst_vmap,
+ struct vm_area_struct **src_vmap)
+{
+ int err;
+
+ mmap_read_lock(mm);
+ err = find_vmas_mm_locked(mm, dst_start, src_start, dst_vmap, src_vmap);
+ if (err)
+ mmap_read_unlock(mm);
+ return err;
+}
+
+static void uffd_move_unlock(struct vm_area_struct *dst_vma,
+ struct vm_area_struct *src_vma)
+{
+ mmap_assert_locked(src_vma->vm_mm);
+ mmap_read_unlock(dst_vma->vm_mm);
}
+#endif
/**
* move_pages - move arbitrary anonymous pages of an existing vma
* @ctx: pointer to the userfaultfd context
- * @mm: the address space to move pages
* @dst_start: start of the destination virtual memory range
* @src_start: start of the source virtual memory range
* @len: length of the virtual memory range
* @mode: flags from uffdio_move.mode
*
- * Must be called with mmap_lock held for read.
+ * It will either use the mmap_lock in read mode or per-vma locks
*
* move_pages() remaps arbitrary anonymous pages atomically in zero
* copy. It only works on non shared anonymous pages because those can
* could be obtained. This is the only additional complexity added to
* the rmap code to provide this anonymous page remapping functionality.
*/
-ssize_t move_pages(struct userfaultfd_ctx *ctx, struct mm_struct *mm,
- unsigned long dst_start, unsigned long src_start,
- unsigned long len, __u64 mode)
+ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
+ unsigned long src_start, unsigned long len, __u64 mode)
{
+ struct mm_struct *mm = ctx->mm;
struct vm_area_struct *src_vma, *dst_vma;
unsigned long src_addr, dst_addr;
pmd_t *src_pmd, *dst_pmd;
WARN_ON_ONCE(dst_start + len <= dst_start))
goto out;
+ err = uffd_move_lock(mm, dst_start, src_start, &dst_vma, &src_vma);
+ if (err)
+ goto out;
+
+ /* Re-check after taking map_changing_lock */
+ err = -EAGAIN;
+ down_read(&ctx->map_changing_lock);
+ if (likely(atomic_read(&ctx->mmap_changing)))
+ goto out_unlock;
/*
* Make sure the vma is not shared, that the src and dst remap
* ranges are both valid and fully within a single existing
* vma.
*/
- src_vma = find_vma(mm, src_start);
- if (!src_vma || (src_vma->vm_flags & VM_SHARED))
- goto out;
- if (src_start < src_vma->vm_start ||
- src_start + len > src_vma->vm_end)
- goto out;
+ err = -EINVAL;
+ if (src_vma->vm_flags & VM_SHARED)
+ goto out_unlock;
+ if (src_start + len > src_vma->vm_end)
+ goto out_unlock;
- dst_vma = find_vma(mm, dst_start);
- if (!dst_vma || (dst_vma->vm_flags & VM_SHARED))
- goto out;
- if (dst_start < dst_vma->vm_start ||
- dst_start + len > dst_vma->vm_end)
- goto out;
+ if (dst_vma->vm_flags & VM_SHARED)
+ goto out_unlock;
+ if (dst_start + len > dst_vma->vm_end)
+ goto out_unlock;
err = validate_move_areas(ctx, src_vma, dst_vma);
if (err)
- goto out;
+ goto out_unlock;
for (src_addr = src_start, dst_addr = dst_start;
src_addr < src_start + len;) {
err = -ENOENT;
break;
}
- /* Avoid moving zeropages for now */
- if (is_huge_zero_pmd(*src_pmd)) {
- spin_unlock(ptl);
- err = -EBUSY;
- break;
- }
/* Check if we can move the pmd without splitting it. */
if (move_splits_huge_pmd(dst_addr, src_addr, src_start + len) ||
!pmd_none(dst_pmdval)) {
struct folio *folio = pfn_folio(pmd_pfn(*src_pmd));
- if (!folio || !PageAnonExclusive(&folio->page)) {
+ if (!folio || (!is_huge_zero_page(&folio->page) &&
+ !PageAnonExclusive(&folio->page))) {
spin_unlock(ptl);
err = -EBUSY;
break;
moved += step_size;
}
+out_unlock:
+ up_read(&ctx->map_changing_lock);
+ uffd_move_unlock(dst_vma, src_vma);
out:
VM_WARN_ON(moved < 0);
VM_WARN_ON(err > 0);
git.samba.org / sfrench / cifs-2.6.git / blobdiff