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authorMike Rapoport <rppt@linux.vnet.ibm.com>2017-02-24 14:58:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-24 17:46:55 -0800
commitca49ca7114553587736fe78319e22f073b631380 (patch)
treeef56409db78f5d218c2aca6b7d49901658a6edaa /fs/userfaultfd.c
parent897ab3e0c49e24b62e2d54d165c7afec6bbca65b (diff)
userfaultfd: non-cooperative: add event for exit() notification
Allow userfaultfd monitor track termination of the processes that have memory backed by the uffd. [rppt@linux.vnet.ibm.com: add comment] Link: http://lkml.kernel.org/r/20170202135448.GB19804@rapoport-lnxLink: http://lkml.kernel.org/r/1485542673-24387-4-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/userfaultfd.c')
-rw-r--r--fs/userfaultfd.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 4c78458ea78d..b676575f2268 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -774,6 +774,34 @@ void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf)
}
}
+void userfaultfd_exit(struct mm_struct *mm)
+{
+ struct vm_area_struct *vma = mm->mmap;
+
+ /*
+ * We can do the vma walk without locking because the caller
+ * (exit_mm) knows it now has exclusive access
+ */
+ while (vma) {
+ struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
+
+ if (ctx && (ctx->features & UFFD_FEATURE_EVENT_EXIT)) {
+ struct userfaultfd_wait_queue ewq;
+
+ userfaultfd_ctx_get(ctx);
+
+ msg_init(&ewq.msg);
+ ewq.msg.event = UFFD_EVENT_EXIT;
+
+ userfaultfd_event_wait_completion(ctx, &ewq);
+
+ ctx->features &= ~UFFD_FEATURE_EVENT_EXIT;
+ }
+
+ vma = vma->vm_next;
+ }
+}
+
static int userfaultfd_release(struct inode *inode, struct file *file)
{
struct userfaultfd_ctx *ctx = file->private_data;