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 --- arch/x86/mm/mpx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/mm') diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index aad4ac386f98..c98079684bdb 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -51,7 +51,7 @@ static unsigned long mpx_mmap(unsigned long len) down_write(&mm->mmap_sem); addr = do_mmap(NULL, 0, len, PROT_READ | PROT_WRITE, - MAP_ANONYMOUS | MAP_PRIVATE, VM_MPX, 0, &populate); + MAP_ANONYMOUS | MAP_PRIVATE, VM_MPX, 0, &populate, NULL); up_write(&mm->mmap_sem); if (populate) mm_populate(addr, populate); @@ -893,7 +893,7 @@ static int unmap_entire_bt(struct mm_struct *mm, * avoid recursion, do_munmap() will check whether it comes * from one bounds table through VM_MPX flag. */ - return do_munmap(mm, bt_addr, mpx_bt_size_bytes(mm)); + return do_munmap(mm, bt_addr, mpx_bt_size_bytes(mm), NULL); } static int try_unmap_single_bt(struct mm_struct *mm, -- cgit v1.2.3