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| author | Peter Xu <peterx@redhat.com> | 2020-04-06 20:06:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-07 10:43:39 -0700 |
| commit | 23080e2783ba45208795faad124eab0e0bdae85a (patch) | |
| tree | 44fed2e3b48fe01ffce463897cf3870f97645160 /fs/userfaultfd.c | |
| parent | e06f1e1dd4998ffc9da37f580703b55a93fc4de4 (diff) | |
| download | lwn-23080e2783ba45208795faad124eab0e0bdae85a.tar.gz lwn-23080e2783ba45208795faad124eab0e0bdae85a.zip | |
userfaultfd: wp: don't wake up when doing write protect
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.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20200220163112.11409-16-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/userfaultfd.c')
| -rw-r--r-- | fs/userfaultfd.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 59e9e399fddb..6e878d23547c 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1812,6 +1812,7 @@ 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; @@ -1830,18 +1831,20 @@ 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); |