From b78594936e1ed56cdf4b6a794a50e00df8377e6b Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Thu, 12 Jan 2017 12:19:16 +1100 Subject: [PATCH] userfaultfd: hugetlbfs: add userfaultfd hugetlb hook Orabug: 21685254 When processing a hugetlb fault for no page present, check the vma to determine if faults are to be handled via userfaultfd. If so, drop the hugetlb_fault_mutex and call handle_userfault(). Link: http://lkml.kernel.org/r/20161216144821.5183-21-aarcange@redhat.com Signed-off-by: Mike Kravetz Signed-off-by: Andrea Arcangeli Acked-by: Hillf Danton Cc: "Dr. David Alan Gilbert" Cc: Michael Rapoport Cc: Mike Rapoport Cc: Pavel Emelyanov Signed-off-by: Andrew Morton (cherry picked from linux-next next-20170117 commit 20609d5667d3db6545062527036875e68451086a) [ Ported to UEK ] Signed-off-by: Mike Kravetz Reviewed-by: Dhaval Giani Signed-off-by: Dhaval Giani --- mm/hugetlb.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5098c726714b0..9417f6f2c597f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -33,6 +33,7 @@ #include #include #include +#include #include "internal.h" int hugepages_treat_as_movable; @@ -3547,6 +3548,27 @@ retry: size = i_size_read(mapping->host) >> huge_page_shift(h); if (idx >= size) goto out; + + /* + * Check for page in userfault range + */ + if (userfaultfd_missing(vma)) { + u32 hash; + + /* + * hugetlb_fault_mutex must be dropped before + * handling userfault. Reacquire after handling + * fault to make calling code simpler. + */ + hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, + idx, address); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + ret = handle_userfault(vma, address, flags, + VM_UFFD_MISSING); + mutex_lock(&hugetlb_fault_mutex_table[hash]); + goto out; + } + page = alloc_huge_page(vma, address, 0); if (IS_ERR(page)) { ret = PTR_ERR(page); -- 2.50.1