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| author | Peter Xu <peterx@redhat.com> | 2022-05-12 20:22:52 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-05-13 07:20:09 -0700 |
| commit | 5c041f5d1f23d3a172dd0db3215634c484b4acd6 (patch) | |
| tree | 07c9d48fc2e21f687e6a8b42bac589c387920051 /fs/userfaultfd.c | |
| parent | 679d103319101800567c8bb7e341b5eee39f6685 (diff) | |
| download | linux-5c041f5d1f23d3a172dd0db3215634c484b4acd6.tar.gz linux-5c041f5d1f23d3a172dd0db3215634c484b4acd6.tar.bz2 linux-5c041f5d1f23d3a172dd0db3215634c484b4acd6.zip | |
mm: teach core mm about pte markers
This patch still does not use pte marker in any way, however it teaches
the core mm about the pte marker idea.
For example, handle_pte_marker() is introduced that will parse and handle
all the pte marker faults.
Many of the places are more about commenting it up - so that we know
there's the possibility of pte marker showing up, and why we don't need
special code for the cases.
[peterx@redhat.com: userfaultfd.c needs swapops.h]
Link: https://lkml.kernel.org/r/YmRlVj3cdizYJsr0@xz-m1.local
Link: https://lkml.kernel.org/r/20220405014833.14015-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/userfaultfd.c')
| -rw-r--r-- | fs/userfaultfd.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index aa0c47cb0d16..78b68e0f9774 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -29,6 +29,7 @@ #include <linux/ioctl.h> #include <linux/security.h> #include <linux/hugetlb.h> +#include <linux/swapops.h> int sysctl_unprivileged_userfaultfd __read_mostly; @@ -249,9 +250,10 @@ static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx, /* * Lockless access: we're in a wait_event so it's ok if it - * changes under us. + * changes under us. PTE markers should be handled the same as none + * ptes here. */ - if (huge_pte_none(pte)) + if (huge_pte_none_mostly(pte)) ret = true; if (!huge_pte_write(pte) && (reason & VM_UFFD_WP)) ret = true; @@ -330,9 +332,10 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx, pte = pte_offset_map(pmd, address); /* * Lockless access: we're in a wait_event so it's ok if it - * changes under us. + * changes under us. PTE markers should be handled the same as none + * ptes here. */ - if (pte_none(*pte)) + if (pte_none_mostly(*pte)) ret = true; if (!pte_write(*pte) && (reason & VM_UFFD_WP)) ret = true; |