From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
Hugh Dickins <hughd@google.com>, Maya Gokhale <gokhale2@llnl.gov>,
Jerome Glisse <jglisse@redhat.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
peterx@redhat.com, Martin Cracauer <cracauer@cons.org>,
Shaohua Li <shli@fb.com>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Marty McFadden <mcfadden8@llnl.gov>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Mel Gorman <mgorman@suse.de>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: [PATCH v4 19/27] userfaultfd: introduce helper vma_find_uffd
Date: Fri, 26 Apr 2019 12:51:43 +0800 [thread overview]
Message-ID: <20190426045151.19556-20-peterx@redhat.com> (raw)
In-Reply-To: <20190426045151.19556-1-peterx@redhat.com>
We've have multiple (and more coming) places that would like to find a
userfault enabled VMA from a mm struct that covers a specific memory
range. This patch introduce the helper for it, meanwhile apply it to
the code.
Suggested-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
mm/userfaultfd.c | 54 +++++++++++++++++++++++++++---------------------
1 file changed, 30 insertions(+), 24 deletions(-)
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 240de2a8492d..2606409572b2 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -20,6 +20,34 @@
#include <asm/tlbflush.h>
#include "internal.h"
+/*
+ * Find a valid userfault enabled VMA region that covers the whole
+ * address range, or NULL on failure. Must be called with mmap_sem
+ * held.
+ */
+static struct vm_area_struct *vma_find_uffd(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long len)
+{
+ struct vm_area_struct *vma = find_vma(mm, start);
+
+ if (!vma)
+ return NULL;
+
+ /*
+ * Check the vma is registered in uffd, this is required to
+ * enforce the VM_MAYWRITE check done at uffd registration
+ * time.
+ */
+ if (!vma->vm_userfaultfd_ctx.ctx)
+ return NULL;
+
+ if (start < vma->vm_start || start + len > vma->vm_end)
+ return NULL;
+
+ return vma;
+}
+
static int mcopy_atomic_pte(struct mm_struct *dst_mm,
pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
@@ -228,20 +256,9 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
*/
if (!dst_vma) {
err = -ENOENT;
- dst_vma = find_vma(dst_mm, dst_start);
+ dst_vma = vma_find_uffd(dst_mm, dst_start, len);
if (!dst_vma || !is_vm_hugetlb_page(dst_vma))
goto out_unlock;
- /*
- * Check the vma is registered in uffd, this is
- * required to enforce the VM_MAYWRITE check done at
- * uffd registration time.
- */
- if (!dst_vma->vm_userfaultfd_ctx.ctx)
- goto out_unlock;
-
- if (dst_start < dst_vma->vm_start ||
- dst_start + len > dst_vma->vm_end)
- goto out_unlock;
err = -EINVAL;
if (vma_hpagesize != vma_kernel_pagesize(dst_vma))
@@ -488,20 +505,9 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
* both valid and fully within a single existing vma.
*/
err = -ENOENT;
- dst_vma = find_vma(dst_mm, dst_start);
+ dst_vma = vma_find_uffd(dst_mm, dst_start, len);
if (!dst_vma)
goto out_unlock;
- /*
- * Check the vma is registered in uffd, this is required to
- * enforce the VM_MAYWRITE check done at uffd registration
- * time.
- */
- if (!dst_vma->vm_userfaultfd_ctx.ctx)
- goto out_unlock;
-
- if (dst_start < dst_vma->vm_start ||
- dst_start + len > dst_vma->vm_end)
- goto out_unlock;
err = -EINVAL;
/*
--
2.17.1
next prev parent reply other threads:[~2019-04-26 4:54 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 4:51 [PATCH v4 00/27] userfaultfd: write protection support Peter Xu
2019-04-26 4:51 ` [PATCH v4 01/27] mm: gup: rename "nonblocking" to "locked" where proper Peter Xu
2019-04-26 4:51 ` [PATCH v4 02/27] mm: userfault: return VM_FAULT_RETRY on signals Peter Xu
2019-04-26 4:51 ` [PATCH v4 03/27] userfaultfd: don't retake mmap_sem to emulate NOPAGE Peter Xu
2019-04-26 4:51 ` [PATCH v4 04/27] mm: allow VM_FAULT_RETRY for multiple times Peter Xu
2019-04-26 4:51 ` [PATCH v4 05/27] mm: gup: " Peter Xu
2019-04-26 4:51 ` [PATCH v4 06/27] userfaultfd: wp: add helper for writeprotect check Peter Xu
2019-04-26 4:51 ` [PATCH v4 07/27] userfaultfd: wp: hook userfault handler to write protection fault Peter Xu
2019-04-26 4:51 ` [PATCH v4 08/27] userfaultfd: wp: add WP pagetable tracking to x86 Peter Xu
2019-04-26 4:51 ` [PATCH v4 09/27] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers Peter Xu
2019-04-26 4:51 ` [PATCH v4 10/27] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Peter Xu
2019-04-26 4:51 ` [PATCH v4 11/27] mm: merge parameters for change_protection() Peter Xu
2019-04-26 4:51 ` [PATCH v4 12/27] userfaultfd: wp: apply _PAGE_UFFD_WP bit Peter Xu
2019-04-26 4:51 ` [PATCH v4 13/27] mm: introduce do_wp_page_cont() Peter Xu
2019-04-26 4:51 ` [PATCH v4 14/27] userfaultfd: wp: handle COW properly for uffd-wp Peter Xu
2019-04-26 4:51 ` [PATCH v4 15/27] userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork Peter Xu
2019-04-26 4:51 ` [PATCH v4 16/27] userfaultfd: wp: add pmd_swp_*uffd_wp() helpers Peter Xu
2019-04-26 4:51 ` [PATCH v4 17/27] userfaultfd: wp: support swap and page migration Peter Xu
2019-04-26 4:51 ` [PATCH v4 18/27] khugepaged: skip collapse if uffd-wp detected Peter Xu
2019-04-26 4:51 ` Peter Xu [this message]
2019-04-26 4:51 ` [PATCH v4 20/27] userfaultfd: wp: support write protection for userfault vma range Peter Xu
2019-04-26 4:51 ` [PATCH v4 21/27] userfaultfd: wp: add the writeprotect API to userfaultfd ioctl Peter Xu
2019-04-26 4:51 ` [PATCH v4 22/27] userfaultfd: wp: enabled write protection in userfaultfd API Peter Xu
2019-04-26 4:51 ` [PATCH v4 23/27] userfaultfd: wp: don't wake up when doing write protect Peter Xu
2019-04-26 4:51 ` [PATCH v4 24/27] userfaultfd: wp: UFFDIO_REGISTER_MODE_WP documentation update Peter Xu
2019-04-26 4:51 ` [PATCH v4 25/27] userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally Peter Xu
2019-04-26 4:51 ` [PATCH v4 26/27] userfaultfd: selftests: refactor statistics Peter Xu
2019-04-26 4:51 ` [PATCH v4 27/27] userfaultfd: selftests: add write-protect test Peter Xu
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