author: Pavel Emelyanov <xemul@parallels.com> 2017-02-22 15:42:40 -0800
committer: Linus Torvalds <torvalds@linux-foundation.org> 2017-02-22 16:41:28 -0800
commit: 05ce77249d5068b057082d24ec22d3824f4816ac
parent: 90794bf19dc19691a16b71bcd75c04094d9e392d
Commit Summary:
Diffstat:
1 file changed, 21 insertions, 0 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 5d37c37854b0..ea9008254df4 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -633,6 +633,34 @@ void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
userfaultfd_event_wait_completion(ctx, &ewq);
}
+void madvise_userfault_dontneed(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start, unsigned long end)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct userfaultfd_ctx *ctx;
+ struct userfaultfd_wait_queue ewq;
+
+ ctx = vma->vm_userfaultfd_ctx.ctx;
+ if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_MADVDONTNEED))
+ return;
+
+ 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_MADVDONTNEED;
+ ewq.msg.arg.madv_dn.start = start;
+ ewq.msg.arg.madv_dn.end = end;
+
+ userfaultfd_event_wait_completion(ctx, &ewq);
+
+ down_read(&mm->mmap_sem);
+}
+
static int userfaultfd_release(struct inode *inode, struct file *file)
{
struct userfaultfd_ctx *ctx = file->private_data;