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John Hubbard eaf4d22a9e docs: mm/gup: pin_user_pages.rst: add a "case 5"
Patch series "vhost, docs: convert to pin_user_pages(), new "case 5""

It recently became clear to me that there are some get_user_pages*()
callers that don't fit neatly into any of the four cases that are so far
listed in pin_user_pages.rst.  vhost.c is one of those.

Add a Case 5 to the documentation, and refer to that when converting
vhost.c.

Thanks to Jan Kara for helping me (again) in understanding the
interaction between get_user_pages() and page writeback [1].

This is based on today's mmotm, which has a nearby patch to
pin_user_pages.rst that rewords cases 3 and 4.

Note that I have only compile-tested the vhost.c patch, although that
does also include cross-compiling for a few other arches.  Any run-time
testing would be greatly appreciated.

[1] https://lore.kernel.org/r/20200529070343.GL14550@quack2.suse.cz

This patch (of 2):

There are four cases listed in pin_user_pages.rst.  These are intended
to help developers figure out whether to use get_user_pages*(), or
pin_user_pages*().  However, the four cases do not cover all the
situations.  For example, drivers/vhost/vhost.c has a "pin, write to
page, set page dirty, unpin" case.

Add a fifth case, to help explain that there is a general pattern that
requires pin_user_pages*() API calls.

[jhubbard@nvidia.com: v2]
  Link: http://lkml.kernel.org/r/20200601052633.853874-2-jhubbard@nvidia.com

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Link: http://lkml.kernel.org/r/20200529234309.484480-1-jhubbard@nvidia.com
Link: http://lkml.kernel.org/r/20200529234309.484480-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-08 11:05:57 -07:00
arch mm/gup.c: convert to use get_user_{page|pages}_fast_only() 2020-06-08 11:05:56 -07:00
block for-5.8/drivers-2020-06-01 2020-06-02 15:37:03 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: engine - do not requeue in case of fatal error 2020-05-28 17:27:52 +10:00
Documentation docs: mm/gup: pin_user_pages.rst: add a "case 5" 2020-06-08 11:05:57 -07:00
drivers Char/Misc driver patches for 5.8-rc1 2020-06-07 10:59:32 -07:00
fs kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases 2020-06-08 11:05:56 -07:00
include mm/gup: introduce pin_user_pages_locked() 2020-06-08 11:05:56 -07:00
init kernel/sysctl: support setting sysctl parameters from kernel command line 2020-06-08 11:05:56 -07:00
ipc ipc/namespace.c: use a work queue to free_ipc 2020-06-08 11:05:56 -07:00
kernel mm/gup.c: convert to use get_user_{page|pages}_fast_only() 2020-06-08 11:05:56 -07:00
lib lib/test_sysctl: support testing of sysctl. boot parameter 2020-06-08 11:05:56 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/gup: documentation fix for pin_user_pages*() APIs 2020-06-08 11:05:56 -07:00
net Kbuild updates for v5.8 2020-06-06 12:00:25 -07:00
samples Kbuild updates for v5.8 2020-06-06 12:00:25 -07:00
scripts Fix for arch/sh build regression with newer binutils, removal of SH5, 2020-06-06 15:22:01 -07:00
security integrity-v5.8 2020-06-06 09:39:05 -07:00
sound powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
tools lib/test_sysctl: support testing of sysctl. boot parameter 2020-06-08 11:05:56 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt mm/gup.c: convert to use get_user_{page|pages}_fast_only() 2020-06-08 11:05:56 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: generate vmlinux.symvers and reuse it for the second modpost 2020-06-06 23:38:12 +09:00
.mailmap A fair amount of stuff this time around, dominated by yet another massive 2020-06-01 15:45:27 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Staging/IIO driver patches for 5.8-rc1 2020-06-07 10:45:08 -07:00
Makefile Kbuild updates for v5.8 2020-06-06 12:00:25 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.