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From: Mike Rapoport <rppt@linux.vnet.ibm.com>
To: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-man@vger.kernel.org,
	Mike Rapoport <rppt@linux.vnet.ibm.com>
Subject: [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
Date: Mon,  1 May 2017 08:43:17 +0300	[thread overview]
Message-ID: <1493617399-20897-4-git-send-email-rppt@linux.vnet.ibm.com> (raw)
In-Reply-To: <1493617399-20897-1-git-send-email-rppt@linux.vnet.ibm.com>

The features handshake is not quite convenient.
Elaborate about it in the BUGS section.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
 man2/ioctl_userfaultfd.2 | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
index e12b9de..50316de 100644
--- a/man2/ioctl_userfaultfd.2
+++ b/man2/ioctl_userfaultfd.2
@@ -650,6 +650,15 @@ operations are Linux-specific.
 .SH EXAMPLE
 See
 .BR userfaultfd (2).
+.SH BUGS
+In order to detect available userfault features and
+enable certain subset of those features
+the usefault file descriptor must be closed after the first
+.BR UFFDIO_API
+operation that queries features availability and re-opened before
+the second
+.BR UFFDIO_API
+call that actually enables the desired features.
 .SH SEE ALSO
 .BR ioctl (2),
 .BR mmap (2),
-- 
1.9.1

  parent reply	other threads:[~2017-05-01  5:43 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-01  5:43 [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update Mike Rapoport
2017-05-01  5:43 ` [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas Mike Rapoport
2017-05-01 18:33   ` Michael Kerrisk (man-pages)
2017-05-02  9:31     ` Mike Rapoport
2017-05-02 20:23       ` Michael Kerrisk (man-pages)
2017-05-01  5:43 ` [PATCH man-pages 2/5] ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description Mike Rapoport
2017-05-01 18:33   ` Michael Kerrisk (man-pages)
2017-05-01  5:43 ` Mike Rapoport [this message]
2017-05-01 18:33   ` [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section Michael Kerrisk (man-pages)
2017-05-02  9:32     ` Mike Rapoport
2017-05-01  5:43 ` [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery Mike Rapoport
2017-05-01 18:33   ` Michael Kerrisk (man-pages)
2017-05-02  9:46     ` Mike Rapoport
2017-05-02 20:27       ` Michael Kerrisk (man-pages)
2017-05-01  5:43 ` [PATCH man-pages 5/5] userfaultfd.2: update VERSIONS section with 4.11 chanegs Mike Rapoport
2017-05-01 18:33   ` Michael Kerrisk (man-pages)
2017-05-01 18:34 ` [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update Michael Kerrisk (man-pages)
2017-05-02  9:48   ` Mike Rapoport
2017-05-02 20:28     ` Michael Kerrisk (man-pages)

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