diff options
| author | Mike Rapoport <rppt@linux.vnet.ibm.com> | 2017-02-08 10:27:33 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2017-02-09 21:53:04 +1100 |
| commit | 43fe4fa30a944c0d034851ed2ab01fd5c86e7107 (patch) | |
| tree | b390d6bcd49fa5f8ae9d31b25f3f005a537f314a /ipc | |
| parent | 6bfb314b102237ded01e3e716d4ec26a9649fa31 (diff) | |
userfaultfd: non-cooperative: add event for memory unmaps
When a non-cooperative userfaultfd monitor copies pages in the background,
it may encounter regions that were already unmapped. Addition of
UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the
virtual memory layout.
Since there might be different uffd contexts for the affected VMAs, we
first should create a temporary representation for the unmap event for
each uffd context and then notify them one by one to the appropriate
userfault file descriptors.
The event notification occurs after the mmap_sem has been released.
Link: http://lkml.kernel.org/r/1485542673-24387-3-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>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/shm.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 7f6537b84ef5..cb95152e2806 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -1222,7 +1222,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, goto invalid; } - addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate); + addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate, NULL); *raddr = addr; err = 0; if (IS_ERR_VALUE(addr)) @@ -1329,7 +1329,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) */ file = vma->vm_file; size = i_size_read(file_inode(vma->vm_file)); - do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); + do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL); /* * We discovered the size of the shm segment, so * break out of here and fall through to the next @@ -1356,7 +1356,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) if ((vma->vm_ops == &shm_vm_ops) && ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) && (vma->vm_file == file)) - do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); + do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL); vma = next; } |