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authorMike Rapoport <rppt@linux.vnet.ibm.com>2017-02-25 01:58:22 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-25 04:46:55 +0300
commit897ab3e0c49e24b62e2d54d165c7afec6bbca65b (patch)
tree5fa7e09864d6c959cef33849f6cb10ed04e459e4 /fs/proc
parent846b1a0f1db065a8479159dd8fecddb1ebf30547 (diff)
downloadlinux-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.tar.xz
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 'fs/proc')
-rw-r--r--fs/proc/vmcore.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index f52d8e857ff7..885d445afa0d 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -388,7 +388,7 @@ static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
}
return 0;
fail:
- do_munmap(vma->vm_mm, from, len);
+ do_munmap(vma->vm_mm, from, len, NULL);
return -EAGAIN;
}
@@ -481,7 +481,7 @@ static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
return 0;
fail:
- do_munmap(vma->vm_mm, vma->vm_start, len);
+ do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
return -EAGAIN;
}
#else