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authorAndrea Arcangeli <aarcange@redhat.com>2015-09-05 01:46:20 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-05 02:54:41 +0300
commit6b251fc96cf2cdf1ce4b5db055547e2a5679bc77 (patch)
tree5c5fdd9cdcd1d67ff74b1ac533e5362567b65098 /mm/memory.c
parent16ba6f811dfe44bc14f7946a4b257b85476fc16e (diff)
downloadlinux-6b251fc96cf2cdf1ce4b5db055547e2a5679bc77.tar.xz
userfaultfd: call handle_userfault() for userfaultfd_missing() faults
This is where the page faults must be modified to call handle_userfault() if userfaultfd_missing() is true (so if the vma->vm_flags had VM_UFFD_MISSING set). handle_userfault() then takes care of blocking the page fault and delivering it to userland. The fault flags must also be passed as parameter so the "read|write" kind of fault can be passed to userland. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 388dcf9aa283..2961fb654369 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -61,6 +61,7 @@
#include <linux/string.h>
#include <linux/dma-debug.h>
#include <linux/debugfs.h>
+#include <linux/userfaultfd_k.h>
#include <asm/io.h>
#include <asm/pgalloc.h>
@@ -2685,6 +2686,12 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (!pte_none(*page_table))
goto unlock;
+ /* Deliver the page fault to userland, check inside PT lock */
+ if (userfaultfd_missing(vma)) {
+ pte_unmap_unlock(page_table, ptl);
+ return handle_userfault(vma, address, flags,
+ VM_UFFD_MISSING);
+ }
goto setpte;
}
@@ -2713,6 +2720,15 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
if (!pte_none(*page_table))
goto release;
+ /* Deliver the page fault to userland, check inside PT lock */
+ if (userfaultfd_missing(vma)) {
+ pte_unmap_unlock(page_table, ptl);
+ mem_cgroup_cancel_charge(page, memcg);
+ page_cache_release(page);
+ return handle_userfault(vma, address, flags,
+ VM_UFFD_MISSING);
+ }
+
inc_mm_counter_fast(mm, MM_ANONPAGES);
page_add_new_anon_rmap(page, vma, address);
mem_cgroup_commit_charge(page, memcg, false);