[PATCH 00/18] random: Include <linux/percpu.h> and resolve circular include dependency

Uros Bizjak ubizjak at gmail.com
Thu Sep 5 05:17:08 PDT 2024


There were several attempts to resolve circular include dependency
after the addition of percpu.h: 1c9df907da83 ("random: fix circular
include dependency on arm64 after addition of percpu.h"), c0842fbc1b18
("random32: move the pseudo-random 32-bit definitions to prandom.h") and
finally d9f29deb7fe8 ("prandom: Remove unused include") that completely
removes inclusion of <linux/percpu.h>.

Due to legacy reasons, <linux/random.h> includes <linux/prandom.h>, but
with the commit entry remark:

--quote--
A further cleanup step would be to remove this from <linux/random.h>
entirely, and make people who use the prandom infrastructure include
just the new header file.  That's a bit of a churn patch, but grepping
for "prandom_" and "next_pseudo_random32" "struct rnd_state" should
catch most users.

But it turns out that that nice cleanup step is fairly painful, because
a _lot_ of code currently seems to depend on the implicit include of
<linux/random.h>, which can currently come in a lot of ways, including
such fairly core headfers as <linux/net.h>.

So the "nice cleanup" part may or may never happen.
--/quote--

__percpu tag is currently defined in include/linux/compiler_types.h,
so there is no direct need for the inclusion of <linux/percpu.h>.
However, in [1] we would like to repurpose __percpu tag as a named
address space qualifier, where __percpu macro uses defines from
<linux/percpu.h>.

This patch series is the "nice cleanup" part, and allows us to finally
include <linux/percpu.h> in prandom.h.

The whole series was tested by compiling the kernel for x86_64 allconfig
and some popular architectures, namely arm64 defconfig, powerpc defconfig
and loongarch defconfig.

[1] https://lore.kernel.org/lkml/20240812115945.484051-4-ubizjak@gmail.com/

Cc: Dave Hansen <dave.hansen at linux.intel.com>
Cc: Andy Lutomirski <luto at kernel.org>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Ingo Molnar <mingo at redhat.com>
Cc: Borislav Petkov <bp at alien8.de>
Cc: x86 at kernel.org
Cc: "H. Peter Anvin" <hpa at zytor.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Tvrtko Ursulin <tursulin at ursulin.net>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: Hans Verkuil <hverkuil at xs4all.nl>
Cc: Mauro Carvalho Chehab <mchehab at kernel.org>
Cc: Miquel Raynal <miquel.raynal at bootlin.com>
Cc: Richard Weinberger <richard at nod.at>
Cc: Vignesh Raghavendra <vigneshr at ti.com>
Cc: Eric Biggers <ebiggers at kernel.org>
Cc: "Theodore Y. Ts'o" <tytso at mit.edu>
Cc: Jaegeuk Kim <jaegeuk at kernel.org>
Cc: "Jason A. Donenfeld" <Jason at zx2c4.com>
Cc: Linus Torvalds <torvalds at linux-foundation.org>
Cc: Hannes Reinecke <hare at suse.de>
Cc: "James E.J. Bottomley" <James.Bottomley at HansenPartnership.com>
Cc: "Martin K. Petersen" <martin.petersen at oracle.com>
Cc: Alexei Starovoitov <ast at kernel.org>
Cc: Daniel Borkmann <daniel at iogearbox.net>
Cc: John Fastabend <john.fastabend at gmail.com>
Cc: Andrii Nakryiko <andrii at kernel.org>
Cc: Martin KaFai Lau <martin.lau at linux.dev>
Cc: Eduard Zingerman <eddyz87 at gmail.com>
Cc: Song Liu <song at kernel.org>
Cc: Yonghong Song <yonghong.song at linux.dev>
Cc: KP Singh <kpsingh at kernel.org>
Cc: Stanislav Fomichev <sdf at fomichev.me>
Cc: Hao Luo <haoluo at google.com>
Cc: Jiri Olsa <jolsa at kernel.org>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Brendan Higgins <brendan.higgins at linux.dev>
Cc: David Gow <davidgow at google.com>
Cc: Rae Moar <rmoar at google.com>
Cc: "David S. Miller" <davem at davemloft.net>
Cc: Eric Dumazet <edumazet at google.com>
Cc: Jakub Kicinski <kuba at kernel.org>
Cc: Paolo Abeni <pabeni at redhat.com>
Cc: Jiri Pirko <jiri at resnulli.us>
Cc: Petr Mladek <pmladek at suse.com>
Cc: Steven Rostedt <rostedt at goodmis.org>
Cc: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
Cc: Rasmus Villemoes <linux at rasmusvillemoes.dk>
Cc: Sergey Senozhatsky <senozhatsky at chromium.org>
Cc: Stephen Hemminger <stephen at networkplumber.org>
Cc: Jamal Hadi Salim <jhs at mojatatu.com>
Cc: Cong Wang <xiyou.wangcong at gmail.com>
Cc: Uros Bizjak <ubizjak at gmail.com>
Cc: Kent Overstreet <kent.overstreet at linux.dev>
Cc: intel-gfx at lists.freedesktop.org
Cc: dri-devel at lists.freedesktop.org
Cc: linux-media at vger.kernel.org
Cc: linux-mtd at lists.infradead.org
Cc: linux-fscrypt at vger.kernel.org
Cc: linux-scsi at vger.kernel.org
Cc: bpf at vger.kernel.org
Cc: linux-kselftest at vger.kernel.org
Cc: kunit-dev at googlegroups.com

Uros Bizjak (18):
  x86/kaslr: Include <linux/prandom.h> instead of <linux/random.h>
  drm/i915/selftests: Include <linux/prandom.h> instead of
    <linux/random.h>
  drm/lib: Include <linux/prandom.h> instead of <linux/random.h>
  media: vivid: Include <linux/prandom.h> in vivid-vid-cap.c
  mtd: tests: Include <linux/prandom.h> instead of <linux/random.h>
  fscrypt: Include <linux/prandom.h> instead of <linux/random.h>
  scsi: libfcoe: Include <linux/prandom.h> instead of <linux/random.h>
  bpf: Include <linux/prandom.h> instead of <linux/random.h>
  lib/interval_tree_test.c: Include <linux/prandom.h> instead of
    <linux/random.h>
  kunit: string-stream-test: Include <linux/prandom.h> instead of
    <linux/random.h>
  random32: Include <linux/prandom.h> instead of <linux/random.h>
  lib/rbtree-test: Include <linux/prandom.h> instead of <linux/random.h>
  bpf/tests: Include <linux/prandom.h> instead of <linux/random.h>
  lib/test_parman: Include <linux/prandom.h> instead of <linux/random.h>
  lib/test_scanf: Include <linux/prandom.h> instead of <linux/random.h>
  netem: Include <linux/prandom.h> in sch_netem.c
  random: Do not include <linux/prandom.h>
  prandom: Include <linux/percpu.h>

 arch/x86/mm/kaslr.c                              | 2 +-
 drivers/gpu/drm/i915/selftests/i915_gem.c        | 2 +-
 drivers/gpu/drm/i915/selftests/i915_random.h     | 2 +-
 drivers/gpu/drm/i915/selftests/scatterlist.c     | 2 +-
 drivers/gpu/drm/lib/drm_random.h                 | 2 +-
 drivers/media/test-drivers/vivid/vivid-vid-cap.c | 1 +
 drivers/mtd/tests/oobtest.c                      | 2 +-
 drivers/mtd/tests/pagetest.c                     | 2 +-
 drivers/mtd/tests/subpagetest.c                  | 2 +-
 fs/crypto/keyring.c                              | 2 +-
 include/linux/prandom.h                          | 1 +
 include/linux/random.h                           | 7 -------
 include/scsi/libfcoe.h                           | 2 +-
 kernel/bpf/core.c                                | 2 +-
 lib/interval_tree_test.c                         | 2 +-
 lib/kunit/string-stream-test.c                   | 1 +
 lib/random32.c                                   | 2 +-
 lib/rbtree_test.c                                | 2 +-
 lib/test_bpf.c                                   | 2 +-
 lib/test_parman.c                                | 2 +-
 lib/test_scanf.c                                 | 2 +-
 net/sched/sch_netem.c                            | 1 +
 22 files changed, 21 insertions(+), 24 deletions(-)

-- 
2.46.0




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