The patch titled
Subject: userfaultfd: hugetlbfs: report the working ioctls for shared hugetlbfs mappings
has been removed from the -mm tree. Its filename was
userfaultfd-shmem-allow-registration-of-shared-memory-ranges-fix.patch
This patch was dropped because it is obsolete
------------------------------------------------------
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Subject: userfaultfd: hugetlbfs: report the working ioctls for shared hugetlbfs mappings
The hugetlbfs support is complete for private mappings, shared mappings
will be working soon. Until that restriction is lifted, it's more correct
not to report UFFDIO_COPY as working for uffd registered shared hugetlbfs
mappings.
This change will prevent userland from getting confused about the ioctls
value returned by UFFDIO_REGISTER.
Link: http://lkml.kernel.org/r/20170215195202.GO25530@xxxxxxxxxx
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Michael Rapoport <RAPOPORT@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff -puN fs/userfaultfd.c~userfaultfd-shmem-allow-registration-of-shared-memory-ranges-fix fs/userfaultfd.c
--- a/fs/userfaultfd.c~userfaultfd-shmem-allow-registration-of-shared-memory-ranges-fix
+++ a/fs/userfaultfd.c
@@ -1113,6 +1113,7 @@ static int userfaultfd_register(struct u
unsigned long vm_flags, new_flags;
bool found;
bool non_anon_pages;
+ bool hugetlbfs_shared_pages;
unsigned long start, end, vma_end;
user_uffdio_register = (struct uffdio_register __user *) arg;
@@ -1179,6 +1180,7 @@ static int userfaultfd_register(struct u
*/
found = false;
non_anon_pages = false;
+ hugetlbfs_shared_pages = false;
for (cur = vma; cur && cur->vm_start < end; cur = cur->vm_next) {
cond_resched();
@@ -1217,7 +1219,12 @@ static int userfaultfd_register(struct u
/*
* Note vmas containing huge pages
*/
- if (is_vm_hugetlb_page(cur) || vma_is_shmem(cur))
+ if (is_vm_hugetlb_page(cur)) {
+ non_anon_pages = true;
+ if (cur->vm_flags & VM_SHARED)
+ hugetlbfs_shared_pages = true;
+ }
+ if (vma_is_shmem(cur))
non_anon_pages = true;
found = true;
@@ -1284,13 +1291,25 @@ out_unlock:
up_write(&mm->mmap_sem);
mmput(mm);
if (!ret) {
+ __u64 ioctls = UFFD_API_RANGE_IOCTLS;
+ if (non_anon_pages)
+ ioctls = UFFD_API_RANGE_IOCTLS_BASIC;
+ /*
+ * This hugetlbfs_shared_pages check should be dropped
+ * in the future, so that the
+ * UFFD_API_RANGE_IOCTLS_BASIC will be reported for
+ * VM_SHARED hugetlbfs vmas too. For now don't mislead
+ * userland in thinking UFFDIO_COPY works on hugetlbfs
+ * shared mappings too.
+ */
+ if (hugetlbfs_shared_pages)
+ ioctls = 0;
/*
* Now that we scanned all vmas we can already tell
* userland which ioctls methods are guaranteed to
* succeed on this range.
*/
- if (put_user(non_anon_pages ? UFFD_API_RANGE_IOCTLS_BASIC :
- UFFD_API_RANGE_IOCTLS,
+ if (put_user(ioctls,
&user_uffdio_register->ioctls))
ret = -EFAULT;
}
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
userfaultfd-document-_ior-_iow.patch
userfaultfd-correct-comment-about-uffd_feature_pagefault_flag_wp.patch
userfaultfd-convert-bug-to-warn_on_once.patch
userfaultfd-use-vma_is_anonymous.patch
userfaultfd-non-cooperative-report-all-available-features-to-userland.patch
userfaultfd-non-cooperative-add-fork-event-build-warning-fix.patch
userfaultfd-non-cooperative-optimize-mremap_userfaultfd_complete.patch
userfaultfd-non-cooperative-avoid-madv_dontneed-race-condition.patch
userfaultfd-non-cooperative-wake-userfaults-after-uffdio_unregister.patch
userfaultfd-hugetlbfs-gup-support-vm_fault_retry.patch
userfaultfd-hugetlbfs-uffd_feature_missing_hugetlbfs.patch
userfaultfd-shmem-add-tlbflushh-header-for-microblaze.patch
userfaultfd-shmem-lock-the-page-before-adding-it-to-pagecache.patch
userfaultfd-shmem-avoid-a-lockup-resulting-from-corrupted-page-flags.patch
userfaultfd-shmem-avoid-leaking-blocks-and-used-blocks-in-uffdio_copy.patch
userfaultfd-hugetlbfs-uffd_feature_missing_shmem.patch
userfaultfd-selftest-test-uffdio_zeropage-on-all-memory-types.patch
mm-mprotect-use-pmd_trans_unstable-instead-of-taking-the-pmd_lock.patch
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