diff options
| 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 (patch) | |
| tree | 818c65b8517abe7dcfd655b590d4c587dad098fe /fs | |
| parent | 90794bf19dc19691a16b71bcd75c04094d9e392d (diff) | |
userfaultfd: non-cooperative: add madvise() event for MADV_DONTNEED request
If the page is punched out of the address space the uffd reader should
know this and zeromap the respective area in case of the #PF event.
Link: http://lkml.kernel.org/r/20161216144821.5183-14-aarcange@redhat.com
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.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 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; |