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path: root/fs/userfaultfd.c
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Diffstat (limited to 'fs/userfaultfd.c')
-rw-r--r--fs/userfaultfd.c28
1 files changed, 22 insertions, 6 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 98ac37e34e3d..cc694846617a 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -108,6 +108,21 @@ static bool userfaultfd_is_initialized(struct userfaultfd_ctx *ctx)
return ctx->features & UFFD_FEATURE_INITIALIZED;
}
+static void userfaultfd_set_vm_flags(struct vm_area_struct *vma,
+ vm_flags_t flags)
+{
+ const bool uffd_wp_changed = (vma->vm_flags ^ flags) & VM_UFFD_WP;
+
+ vma->vm_flags = flags;
+ /*
+ * For shared mappings, we want to enable writenotify while
+ * userfaultfd-wp is enabled (see vma_wants_writenotify()). We'll simply
+ * recalculate vma->vm_page_prot whenever userfaultfd-wp changes.
+ */
+ if ((vma->vm_flags & VM_SHARED) && uffd_wp_changed)
+ vma_set_page_prot(vma);
+}
+
static int userfaultfd_wake_function(wait_queue_entry_t *wq, unsigned mode,
int wake_flags, void *key)
{
@@ -618,7 +633,8 @@ static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
for_each_vma(vmi, vma) {
if (vma->vm_userfaultfd_ctx.ctx == release_new_ctx) {
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
- vma->vm_flags &= ~__VM_UFFD_FLAGS;
+ userfaultfd_set_vm_flags(vma,
+ vma->vm_flags & ~__VM_UFFD_FLAGS);
}
}
mmap_write_unlock(mm);
@@ -652,7 +668,7 @@ int dup_userfaultfd(struct vm_area_struct *vma, struct list_head *fcs)
octx = vma->vm_userfaultfd_ctx.ctx;
if (!octx || !(octx->features & UFFD_FEATURE_EVENT_FORK)) {
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
- vma->vm_flags &= ~__VM_UFFD_FLAGS;
+ userfaultfd_set_vm_flags(vma, vma->vm_flags & ~__VM_UFFD_FLAGS);
return 0;
}
@@ -733,7 +749,7 @@ void mremap_userfaultfd_prep(struct vm_area_struct *vma,
} else {
/* Drop uffd context if remap feature not enabled */
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
- vma->vm_flags &= ~__VM_UFFD_FLAGS;
+ userfaultfd_set_vm_flags(vma, vma->vm_flags & ~__VM_UFFD_FLAGS);
}
}
@@ -895,7 +911,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
prev = vma;
}
- vma->vm_flags = new_flags;
+ userfaultfd_set_vm_flags(vma, new_flags);
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
}
mmap_write_unlock(mm);
@@ -1463,7 +1479,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
* the next vma was merged into the current one and
* the current one has not been updated yet.
*/
- vma->vm_flags = new_flags;
+ userfaultfd_set_vm_flags(vma, new_flags);
vma->vm_userfaultfd_ctx.ctx = ctx;
if (is_vm_hugetlb_page(vma) && uffd_disable_huge_pmd_share(vma))
@@ -1651,7 +1667,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
* the next vma was merged into the current one and
* the current one has not been updated yet.
*/
- vma->vm_flags = new_flags;
+ userfaultfd_set_vm_flags(vma, new_flags);
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
skip: