diff options
| author | Mike Kravetz <mike.kravetz@oracle.com> | 2017-02-22 15:43:01 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-22 16:41:28 -0800 |
| commit | 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 (patch) | |
| tree | 327e1b523dc7cd0e34321ac3dcf5e34ae43a6060 | |
| parent | 810a56b943e265bbabfcd5a8e54cb8d3b16cd6e4 (diff) | |
userfaultfd: hugetlbfs: add userfaultfd hugetlb hook
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 <mike.kravetz@oracle.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/hugetlb.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5d20af921a30..a4b29054cc3f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -32,6 +32,7 @@ #include <linux/hugetlb.h> #include <linux/hugetlb_cgroup.h> #include <linux/node.h> +#include <linux/userfaultfd_k.h> #include "internal.h" int hugepages_treat_as_movable; @@ -3680,6 +3681,38 @@ 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; + struct vm_fault vmf = { + .vma = vma, + .address = address, + .flags = flags, + /* + * Hard to debug if it ends up being + * used by a callee that assumes + * something about the other + * uninitialized fields... same as in + * memory.c + */ + }; + + /* + * 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(&vmf, 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); |