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>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Shaohua Li <shli@fb.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 v5 21/25] userfaultfd: wp: don't wake up when doing write protect
Date: Thu, 20 Jun 2019 10:20:04 +0800 [thread overview]
Message-ID: <20190620022008.19172-22-peterx@redhat.com> (raw)
In-Reply-To: <20190620022008.19172-1-peterx@redhat.com>
It does not make sense to try to wake up any waiting thread when we're
write-protecting a memory region. Only wake up when resolving a write
protected page fault.
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
fs/userfaultfd.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 3cf19aeaa0e0..498971fa9163 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1782,6 +1782,7 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx,
struct uffdio_writeprotect uffdio_wp;
struct uffdio_writeprotect __user *user_uffdio_wp;
struct userfaultfd_wake_range range;
+ bool mode_wp, mode_dontwake;
if (READ_ONCE(ctx->mmap_changing))
return -EAGAIN;
@@ -1800,18 +1801,20 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx,
if (uffdio_wp.mode & ~(UFFDIO_WRITEPROTECT_MODE_DONTWAKE |
UFFDIO_WRITEPROTECT_MODE_WP))
return -EINVAL;
- if ((uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP) &&
- (uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE))
+
+ mode_wp = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP;
+ mode_dontwake = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE;
+
+ if (mode_wp && mode_dontwake)
return -EINVAL;
ret = mwriteprotect_range(ctx->mm, uffdio_wp.range.start,
- uffdio_wp.range.len, uffdio_wp.mode &
- UFFDIO_WRITEPROTECT_MODE_WP,
+ uffdio_wp.range.len, mode_wp,
&ctx->mmap_changing);
if (ret)
return ret;
- if (!(uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE)) {
+ if (!mode_wp && !mode_dontwake) {
range.start = uffdio_wp.range.start;
range.len = uffdio_wp.range.len;
wake_userfault(ctx, &range);
--
2.21.0
next prev parent reply other threads:[~2019-06-20 2:24 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 2:19 [PATCH v5 00/25] userfaultfd: write protection support Peter Xu
2019-06-20 2:19 ` [PATCH v5 01/25] mm: gup: rename "nonblocking" to "locked" where proper Peter Xu
2019-06-20 2:19 ` [PATCH v5 02/25] mm: userfault: return VM_FAULT_RETRY on signals Peter Xu
2019-06-22 18:02 ` Linus Torvalds
2019-06-24 7:42 ` Peter Xu
2019-06-24 13:31 ` Linus Torvalds
2019-06-25 5:30 ` Peter Xu
2019-06-26 1:59 ` Linus Torvalds
2019-06-26 7:43 ` Peter Xu
2019-06-20 2:19 ` [PATCH v5 03/25] userfaultfd: don't retake mmap_sem to emulate NOPAGE Peter Xu
2019-06-20 2:19 ` [PATCH v5 04/25] mm: allow VM_FAULT_RETRY for multiple times Peter Xu
2019-06-20 2:19 ` [PATCH v5 05/25] mm: gup: " Peter Xu
2019-06-20 2:19 ` [PATCH v5 06/25] userfaultfd: wp: add helper for writeprotect check Peter Xu
2019-06-20 2:19 ` [PATCH v5 07/25] userfaultfd: wp: hook userfault handler to write protection fault Peter Xu
2019-06-20 2:19 ` [PATCH v5 08/25] userfaultfd: wp: add WP pagetable tracking to x86 Peter Xu
2019-06-20 2:19 ` [PATCH v5 09/25] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers Peter Xu
2019-06-20 2:19 ` [PATCH v5 10/25] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Peter Xu
2019-06-20 2:19 ` [PATCH v5 11/25] mm: merge parameters for change_protection() Peter Xu
2019-06-20 2:19 ` [PATCH v5 12/25] userfaultfd: wp: apply _PAGE_UFFD_WP bit Peter Xu
2019-06-20 2:19 ` [PATCH v5 13/25] userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork Peter Xu
2019-06-20 2:19 ` [PATCH v5 14/25] userfaultfd: wp: add pmd_swp_*uffd_wp() helpers Peter Xu
2019-06-20 2:19 ` [PATCH v5 15/25] userfaultfd: wp: support swap and page migration Peter Xu
2019-06-20 2:19 ` [PATCH v5 16/25] khugepaged: skip collapse if uffd-wp detected Peter Xu
2019-06-20 2:20 ` [PATCH v5 17/25] userfaultfd: introduce helper vma_find_uffd Peter Xu
2019-06-20 2:20 ` [PATCH v5 18/25] userfaultfd: wp: support write protection for userfault vma range Peter Xu
2019-06-20 2:20 ` [PATCH v5 19/25] userfaultfd: wp: add the writeprotect API to userfaultfd ioctl Peter Xu
2019-06-20 2:20 ` [PATCH v5 20/25] userfaultfd: wp: enabled write protection in userfaultfd API Peter Xu
2019-06-20 2:20 ` Peter Xu [this message]
2019-06-20 2:20 ` [PATCH v5 22/25] userfaultfd: wp: UFFDIO_REGISTER_MODE_WP documentation update Peter Xu
2019-06-20 2:20 ` [PATCH v5 23/25] userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally Peter Xu
2019-06-20 2:20 ` [PATCH v5 24/25] userfaultfd: selftests: refactor statistics Peter Xu
2019-06-20 2:20 ` [PATCH v5 25/25] userfaultfd: selftests: add write-protect test Peter Xu
2019-06-23 8:39 ` [PATCH v5 10/25] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Hillf Danton
2020-02-18 3:59 ` [PATCH v5 00/25] userfaultfd: write protection support Bobby Powers
2020-02-18 16:11 ` Peter Xu
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