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authorMike Rapoport <rppt@linux.vnet.ibm.com>2017-02-24 14:58:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-24 17:46:55 -0800
commit897ab3e0c49e24b62e2d54d165c7afec6bbca65b (patch)
tree5fa7e09864d6c959cef33849f6cb10ed04e459e4 /mm/util.c
parent846b1a0f1db065a8479159dd8fecddb1ebf30547 (diff)
downloadop-kernel-dev-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.zip
op-kernel-dev-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.tar.gz
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 'mm/util.c')
-rw-r--r--mm/util.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/util.c b/mm/util.c
index 3cb2164..b8f5388 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -11,6 +11,7 @@
#include <linux/mman.h>
#include <linux/hugetlb.h>
#include <linux/vmalloc.h>
+#include <linux/userfaultfd_k.h>
#include <asm/sections.h>
#include <linux/uaccess.h>
@@ -297,14 +298,16 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
unsigned long ret;
struct mm_struct *mm = current->mm;
unsigned long populate;
+ LIST_HEAD(uf);
ret = security_mmap_file(file, prot, flag);
if (!ret) {
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
- &populate);
+ &populate, &uf);
up_write(&mm->mmap_sem);
+ userfaultfd_unmap_complete(mm, &uf);
if (populate)
mm_populate(ret, populate);
}
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