diff options
| author | Mike Rapoport <rppt@linux.vnet.ibm.com> | 2017-02-24 14:58:25 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-24 17:46:55 -0800 |
| commit | ca49ca7114553587736fe78319e22f073b631380 (patch) | |
| tree | ef56409db78f5d218c2aca6b7d49901658a6edaa /fs | |
| parent | 897ab3e0c49e24b62e2d54d165c7afec6bbca65b (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')
| -rw-r--r-- | fs/userfaultfd.c | 28 |
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; |