From 897ab3e0c49e24b62e2d54d165c7afec6bbca65b Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Fri, 24 Feb 2017 14:58:22 -0800 Subject: 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 Signed-off-by: Michal Hocko Signed-off-by: Arnd Bergmann Acked-by: Hillf Danton Cc: Andrea Arcangeli Cc: "Dr. David Alan Gilbert" Cc: Mike Kravetz Cc: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/vmcore.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/proc/vmcore.c') 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 -- cgit v1.2.3