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Mike Marshall 974ca069d5 orangefs: get rid of knob code...
commit ec95f1dedc upstream.

Christoph Hellwig sent in a reversion of "orangefs: remember count
when reading." because:

  ->read_iter calls can race with each other and one or
  more ->flush calls. Remove the the scheme to store the read
  count in the file private data as is is completely racy and
  can cause use after free or double free conditions

Christoph's reversion caused Orangefs not to work or to compile. I
added a patch that fixed that, but intel's kbuild test robot pointed
out that sending Christoph's patch followed by my patch upstream, it
would break bisection because of the failure to compile. So I have
combined the reversion plus my patch... here's the commit message
that was in my patch:

  Logically, optimal Orangefs "pages" are 4 megabytes. Reading
  large Orangefs files 4096 bytes at a time is like trying to
  kick a dead whale down the beach. Before Christoph's "Revert
  orangefs: remember count when reading." I tried to give users
  a knob whereby they could, for example, use "count" in
  read(2) or bs with dd(1) to get whatever they considered an
  appropriate amount of bytes at a time from Orangefs and fill
  as many page cache pages as they could at once.

  Without the racy code that Christoph reverted Orangefs won't
  even compile, much less work. So this replaces the logic that
  used the private file data that Christoph reverted with
  a static number of bytes to read from Orangefs.

  I ran tests like the following to determine what a
  reasonable static number of bytes might be:

  dd if=/pvfsmnt/asdf of=/dev/null count=128 bs=4194304
  dd if=/pvfsmnt/asdf of=/dev/null count=256 bs=2097152
  dd if=/pvfsmnt/asdf of=/dev/null count=512 bs=1048576
                            .
                            .
                            .
  dd if=/pvfsmnt/asdf of=/dev/null count=4194304 bs=128

  Reads seem faster using the static number, so my "knob code"
  wasn't just racy, it wasn't even a good idea...

Signed-off-by: Mike Marshall <hubcap@omnibond.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-21 13:05:29 +02:00
Documentation dt-bindings: iio: io-channel-mux: Fix compatible string in example code 2020-08-21 13:05:23 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch pseries: Fix 64 bit logical memory block panic 2020-08-21 13:05:28 +02:00
block iocost: Fix check condition of iocg abs_vdebt 2020-08-19 08:15:58 +02:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto keys: asymmetric: fix error return code in software_key_query() 2020-07-22 09:33:04 +02:00
drivers drm/imx: imx-ldb: Disable both channels for split mode in enc->disable() 2020-08-21 13:05:29 +02:00
fs orangefs: get rid of knob code... 2020-08-21 13:05:29 +02:00
include net/compat: Add missing sock updates for SCM_RIGHTS 2020-08-21 13:05:25 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel module: Correctly truncate sysfs sections output 2020-08-21 13:05:28 +02:00
lib kobject: Avoid premature parent object freeing in kobject_cleanup() 2020-08-19 08:16:11 +02:00
mm mm/memory_hotplug: fix unpaired mem_hotplug_begin/done 2020-08-21 13:05:27 +02:00
net mac80211: fix misplaced while instead of if 2020-08-21 13:05:26 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts recordmcount: only record relocation of type R_AARCH64_CALL26 on arm64. 2020-08-19 08:15:57 +02:00
security Smack: prevent underflow in smk_set_cipso() 2020-08-19 08:16:16 +02:00
sound ALSA: usb-audio: add quirk for Pioneer DDJ-RB 2020-08-19 08:16:27 +02:00
tools perf intel-pt: Fix duplicate branch after CBR 2020-08-21 13:05:29 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Don't inherit exec permission across page-table levels 2020-08-05 09:59:51 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +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: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 17:22:19 +01:00
Makefile Linux 5.4.59 2020-08-19 08:16:29 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

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.