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| author | Mike Rapoport <rppt@linux.vnet.ibm.com> | 2017-02-24 14:58:22 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-24 17:46:55 -0800 |
| commit | 897ab3e0c49e24b62e2d54d165c7afec6bbca65b (patch) | |
| tree | 5fa7e09864d6c959cef33849f6cb10ed04e459e4 /ipc/shm.c | |
| parent | 846b1a0f1db065a8479159dd8fecddb1ebf30547 (diff) | |
| download | lwn-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.tar.gz lwn-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.zip | |
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.
[arnd@arndb.de: fix nommu build]
Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de
[mhocko@suse.com: fix nommu build]
Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz
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>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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 'ipc/shm.c')
| -rw-r--r-- | ipc/shm.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 7f6537b84ef5..d7805acb44fd 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; } @@ -1365,7 +1365,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) * given */ if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { - 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); retval = 0; } |