userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEED

[karo-tx-linux.git] / fs / userfaultfd.c

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 2407249998c326e178087f65eb1500954e32abf1..9fd5e51ffb316d64333653ca72e8235d3407d157 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -695,8 +695,7 @@ void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
        userfaultfd_event_wait_completion(ctx, &ewq);
 }
 
-void userfaultfd_remove(struct vm_area_struct *vma,
-                       struct vm_area_struct **prev,
+bool userfaultfd_remove(struct vm_area_struct *vma,
                        unsigned long start, unsigned long end)
 {
        struct mm_struct *mm = vma->vm_mm;
@@ -705,13 +704,11 @@ void userfaultfd_remove(struct vm_area_struct *vma,
 
        ctx = vma->vm_userfaultfd_ctx.ctx;
        if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_REMOVE))
-               return;
+               return true;
 
        userfaultfd_ctx_get(ctx);
        up_read(&mm->mmap_sem);
 
-       *prev = NULL; /* We wait for ACK w/o the mmap semaphore */
-
        msg_init(&ewq.msg);
 
        ewq.msg.event = UFFD_EVENT_REMOVE;
@@ -720,7 +717,7 @@ void userfaultfd_remove(struct vm_area_struct *vma,
 
        userfaultfd_event_wait_completion(ctx, &ewq);
 
-       down_read(&mm->mmap_sem);
+       return false;
 }
 
 static bool has_unmap_ctx(struct userfaultfd_ctx *ctx, struct list_head *unmaps,