Commit Graph

5516 Commits

Author SHA1 Message Date
Linus Torvalds 2c1212de6f Merge tag 'spdx-5.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull SPDX update from Greg KH:
 "Here is a series of patches that add SPDX tags to different kernel
  files, based on two different things:

   - SPDX entries are added to a bunch of files that we missed a year
     ago that do not have any license information at all.

     These were either missed because the tool saw the MODULE_LICENSE()
     tag, or some EXPORT_SYMBOL tags, and got confused and thought the
     file had a real license, or the files have been added since the
     last big sweep, or they were Makefile/Kconfig files, which we
     didn't touch last time.

   - Add GPL-2.0-only or GPL-2.0-or-later tags to files where our scan
     tools can determine the license text in the file itself. Where this
     happens, the license text is removed, in order to cut down on the
     700+ different ways we have in the kernel today, in a quest to get
     rid of all of these.

  These patches have been out for review on the linux-spdx@vger mailing
  list, and while they were created by automatic tools, they were
  hand-verified by a bunch of different people, all whom names are on
  the patches are reviewers.

  The reason for these "large" patches is if we were to continue to
  progress at the current rate of change in the kernel, adding license
  tags to individual files in different subsystems, we would be finished
  in about 10 years at the earliest.

  There will be more series of these types of patches coming over the
  next few weeks as the tools and reviewers crunch through the more
  "odd" variants of how to say "GPLv2" that developers have come up with
  over the years, combined with other fun oddities (GPL + a BSD
  disclaimer?) that are being unearthed, with the goal for the whole
  kernel to be cleaned up.

  These diffstats are not small, 3840 files are touched, over 10k lines
  removed in just 24 patches"

* tag 'spdx-5.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (24 commits)
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 24
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 23
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 22
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 21
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 20
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 19
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 18
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 17
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 15
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 14
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 12
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 11
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 10
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 9
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 7
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 5
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 4
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 3
  ...
2019-05-21 12:33:38 -07:00
Thomas Gleixner aded9cb878 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 10
Based on 1 normalized pattern(s):

  licensed under the fsf s gnu public license v2 or later

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 2 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154041.526489261@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 11:28:45 +02:00
Thomas Gleixner ec8f24b7fa treewide: Add SPDX license identifier - Makefile/Kconfig
Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:46 +02:00
Thomas Gleixner 09c434b8a0 treewide: Add SPDX license identifier for more missed files
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have MODULE_LICENCE("GPL*") inside which was used in the initial
   scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:45 +02:00
Thomas Gleixner 457c899653 treewide: Add SPDX license identifier for missed files
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:45 +02:00
Linus Torvalds 78e0365184 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:1) Use after free in __dev_map_entry_free(), from Eric Dumazet.

 1) Use after free in __dev_map_entry_free(), from Eric Dumazet.

 2) Fix TCP retransmission timestamps on passive Fast Open, from Yuchung
    Cheng.

 3) Orphan NFC, we'll take the patches directly into my tree. From
    Johannes Berg.

 4) We can't recycle cloned TCP skbs, from Eric Dumazet.

 5) Some flow dissector bpf test fixes, from Stanislav Fomichev.

 6) Fix RCU marking and warnings in rhashtable, from Herbert Xu.

 7) Fix some potential fib6 leaks, from Eric Dumazet.

 8) Fix a _decode_session4 uninitialized memory read bug fix that got
    lost in a merge. From Florian Westphal.

 9) Fix ipv6 source address routing wrt. exception route entries, from
    Wei Wang.

10) The netdev_xmit_more() conversion was not done %100 properly in mlx5
    driver, fix from Tariq Toukan.

11) Clean up botched merge on netfilter kselftest, from Florian
    Westphal.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (74 commits)
  of_net: fix of_get_mac_address retval if compiled without CONFIG_OF
  net: fix kernel-doc warnings for socket.c
  net: Treat sock->sk_drops as an unsigned int when printing
  kselftests: netfilter: fix leftover net/net-next merge conflict
  mlxsw: core: Prevent reading unsupported slave address from SFP EEPROM
  mlxsw: core: Prevent QSFP module initialization for old hardware
  vsock/virtio: Initialize core virtio vsock before registering the driver
  net/mlx5e: Fix possible modify header actions memory leak
  net/mlx5e: Fix no rewrite fields with the same match
  net/mlx5e: Additional check for flow destination comparison
  net/mlx5e: Add missing ethtool driver info for representors
  net/mlx5e: Fix number of vports for ingress ACL configuration
  net/mlx5e: Fix ethtool rxfh commands when CONFIG_MLX5_EN_RXNFC is disabled
  net/mlx5e: Fix wrong xmit_more application
  net/mlx5: Fix peer pf disable hca command
  net/mlx5: E-Switch, Correct type to u16 for vport_num and int for vport_index
  net/mlx5: Add meaningful return codes to status_to_err function
  net/mlx5: Imply MLXFW in mlx5_core
  Revert "tipc: fix modprobe tipc failed after switch order of device registration"
  vsock/virtio: free packets during the socket release
  ...
2019-05-20 08:21:07 -07:00
Philippe Mazenauer 38a04b83ab lib: Correct comment of prandom_seed
Variable 'entropy' was wrongly documented as 'seed', changed comment to
reflect actual variable name.

../lib/random32.c:179: warning: Function parameter or member 'entropy' not described in 'prandom_seed'
../lib/random32.c:179: warning: Excess function parameter 'seed' description in 'prandom_seed'

Signed-off-by: Philippe Mazenauer <philippe.mazenauer@outlook.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-17 11:32:47 -07:00
Qian Cai 7878c231da slab: remove /proc/slab_allocators
It turned out that DEBUG_SLAB_LEAK is still broken even after recent
recue efforts that when there is a large number of objects like
kmemleak_object which is normal on a debug kernel,

  # grep kmemleak /proc/slabinfo
  kmemleak_object   2243606 3436210 ...

reading /proc/slab_allocators could easily loop forever while processing
the kmemleak_object cache and any additional freeing or allocating
objects will trigger a reprocessing. To make a situation worse,
soft-lockups could easily happen in this sitatuion which will call
printk() to allocate more kmemleak objects to guarantee an infinite
loop.

Also, since it seems no one had noticed when it was totally broken
more than 2-year ago - see the commit fcf88917dd ("slab: fix a crash
by reading /proc/slab_allocators"), probably nobody cares about it
anymore due to the decline of the SLAB. Just remove it entirely.

Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-16 15:51:55 -07:00
Linus Torvalds 27ebbf9d5b Merge tag 'asm-generic-nommu' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull nommu generic uaccess updates from Arnd Bergmann:
 "asm-generic: kill <asm/segment.h> and improve nommu generic uaccess helpers

  Christoph Hellwig writes:

     This is a series doing two somewhat interwinded things. It improves
     the asm-generic nommu uaccess helper to optionally be entirely
     generic and not require any arch helpers for the actual uaccess.
     For the generic uaccess.h to actually be generically useful I also
     had to kill off the mess we made of <asm/segment.h>, which really
     shouldn't exist on most architectures"

* tag 'asm-generic-nommu' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  asm-generic: optimize generic uaccess for 8-byte loads and stores
  asm-generic: provide entirely generic nommu uaccess
  arch: mostly remove <asm/segment.h>
  asm-generic: don't include <asm/segment.h> from <asm/uaccess.h>
2019-05-16 11:26:37 -07:00
Herbert Xu e9458a4e33 rhashtable: Fix cmpxchg RCU warnings
As cmpxchg is a non-RCU mechanism it will cause sparse warnings
when we use it for RCU.  This patch adds explicit casts to silence
those warnings.  This should probably be moved to RCU itself in
future.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-16 09:45:20 -07:00
Herbert Xu ba6306e3f6 rhashtable: Remove RCU marking from rhash_lock_head
The opaque type rhash_lock_head should not be marked with __rcu
because it can never be dereferenced.  We should apply the RCU
marking when we turn it into a pointer which can be dereferenced.

This patch does exactly that.  This fixes a number of sparse
warnings as well as getting rid of some unnecessary RCU checking.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-16 09:45:20 -07:00
Ingo Molnar 00f5764dbb Merge branch 'linus' into x86/urgent, to pick up dependent changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-05-16 09:04:48 +02:00
Eric Sandeen 2ea622b887 tools/testing/selftests/sysctl/sysctl.sh: add proc_do_large_bitmap() test case
The kernel has only two users of proc_do_large_bitmap(), the kernel CPU
watchdog, and the ip_local_reserved_ports.  Refer to watchdog_cpumask
and ip_local_reserved_ports in Documentation for further details on
these.  When you input a large buffer into these, when it is larger than
PAGE_SIZE- 1, the input data gets misparsed, and the user get
incorrectly informed that the desired input value was set.  This commit
implements a test which mimics and exploits that use case, it uses a
bitmap size, as in the watchdog case.  The bitmap is used to test the
bitmap proc handler, proc_do_large_bitmap().

The next commit fixes this issue.

[akpm@linux-foundation.org: move proc_do_large_bitmap() export to EOF]
[mcgrof@kernel.org: use new target description for backward compatibility]
[mcgrof@kernel.org: augment test number to 50, ran into issues with bash string comparisons when testing up to 50 cases.]
[mcgrof@kernel.org: introduce and use verify_diff_proc_file() to use diff]
[mcgrof@kernel.org: use mktemp for tmp file]
[mcgrof@kernel.org: merge shell test and C code]
[mcgrof@kernel.org: commit log love]
[mcgrof@kernel.org: export proc_do_large_bitmap() to allow for the test
[mcgrof@kernel.org: check for the return value when writing to the proc file]
Link: http://lkml.kernel.org/r/20190320222831.8243-6-mcgrof@kernel.org
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:51 -07:00
Sinan Kaya c66d7a27b7 init: introduce DEBUG_MISC option
Patch series "init: Do not select DEBUG_KERNEL by default", v5.

CONFIG_DEBUG_KERNEL has been designed to just enable Kconfig options.
Kernel code generatoin should not depend on CONFIG_DEBUG_KERNEL.

Proposed alternative plan: let's add a new symbol, something like
DEBUG_MISC ("Miscellaneous debug code that should be under a more
specific debug option but isn't"), make it depend on DEBUG_KERNEL and be
"default DEBUG_KERNEL" but allow itself to be turned off, and then
mechanically change the small handful of "#ifdef CONFIG_DEBUG_KERNEL" to
"#ifdef CONFIG_DEBUG_MISC".

This patch (of 5):

Introduce DEBUG_MISC ("Miscellaneous debug code that should be under a
more specific debug option but isn't"), make it depend on DEBUG_KERNEL
and be "default DEBUG_KERNEL" but allow itself to be turned off, and
then mechanically change the small handful of "#ifdef
CONFIG_DEBUG_KERNEL" to "#ifdef CONFIG_DEBUG_MISC".

Link: http://lkml.kernel.org/r/20190413224438.10802-2-okaya@kernel.org
Signed-off-by: Sinan Kaya <okaya@kernel.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc:  Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Florian Westphal <fw@strlen.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:50 -07:00
Andrew Morton 7507c40258 lib/test_vmalloc.c:test_func(): eliminate local `ret'
Local 'ret' is unneeded and was poorly named: the variable `ret'
generally means the "the value which this function will return".

Cc: Roman Gushchin <guro@fb.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
Yury Norov 6ea86bdfc1 lib/test_bitmap: add tests for bitmap_parselist_user()
Propagate existing bitmap_parselist() tests to bitmap_parselist_user().

Link: http://lkml.kernel.org/r/20190405173211.11373-6-ynorov@marvell.com
Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
Yury Norov a4ab50509c lib/test_bitmap: add testcases for bitmap_parselist()
Add tests for non-number character, empty regions, integer overflow.

[ynorov@marvell.com: v5]
  Link: http://lkml.kernel.org/r/20190416063801.20134-5-ynorov@marvell.com
Link: http://lkml.kernel.org/r/20190405173211.11373-5-ynorov@marvell.com
Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
Yury Norov 0c2111a5c8 lib/test_bitmap: switch test_bitmap_parselist to ktime_get()
test_bitmap_parselist currently uses get_cycles which is not implemented
on some platforms, so use ktime_get() instead.

Link: http://lkml.kernel.org/r/20190405173211.11373-4-ynorov@marvell.com
Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
Yury Norov e371c481d8 lib: rework bitmap_parselist
Remove __bitmap_parselist helper and split the function to logical
parts.

[ynorov@marvell.com: v5]
  Link: http://lkml.kernel.org/r/20190416063801.20134-3-ynorov@marvell.com
Link: http://lkml.kernel.org/r/20190405173211.11373-3-ynorov@marvell.com
Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
Yury Norov 281327c99b lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()
Patch series "lib: rework bitmap_parselist and tests", v5.

bitmap_parselist has been evolved from a pretty simple idea for long and
now lacks for refactoring.  It is not structured, has nested loops and a
set of opaque-named variables.

Things are more complicated because bitmap_parselist() is a part of user
interface, and its behavior should not change.

In this patchset
 - bitmap_parselist_user() made a wrapper on bitmap_parselist();
 - bitmap_parselist() reworked (patch 2);
 - time measurement in test_bitmap_parselist switched to ktime_get
   (patch 3);
 - new tests introduced (patch 4), and
 - bitmap_parselist_user() testing enabled with the same testset as
   bitmap_parselist() (patch 5).

This patch (of 5):

Currently we parse user data byte after byte which leads to
overcomplification of parsing algorithm.  The only user of
bitmap_parselist_user() is not performance-critical, and so we can
duplicate user data to kernel buffer and simply call bitmap_parselist().
This rework lets us unify and simplify bitmap_parselist() and
bitmap_parselist_user(), which is done in the following patch.

Link: http://lkml.kernel.org/r/20190405173211.11373-2-ynorov@marvell.com
Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Mike Travis <travis@sgi.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
Andy Shevchenko 9f61589469 lib/math: move int_pow() from pwm_bl.c for wider use
The integer exponentiation is used in few places and might be used in
the future by other call sites.  Move it to wider use.

Link: http://lkml.kernel.org/r/20190323172531.80025-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
Andy Shevchenko 2c64e9cb0b lib: Move mathematic helpers to separate folder
For better maintenance and expansion move the mathematic helpers to the
separate folder.

No functional change intended.

Note, the int_sqrt() is not used as a part of lib, so, moved to regular
obj.

Link: http://lkml.kernel.org/r/20190323172531.80025-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Ray Jui <rjui@broadcom.com>
[mchehab+samsung@kernel.org: fix broken doc references for div64.c and gcd.c]
  Link: http://lkml.kernel.org/r/734f49bae5d4052b3c25691dfefad59bea2e5843.1555580999.git.mchehab+samsung@kernel.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
George Spelvin b5c56e0cdd lib/list_sort: optimize number of calls to comparison function
CONFIG_RETPOLINE has severely degraded indirect function call
performance, so it's worth putting some effort into reducing the number
of times cmp() is called.

This patch avoids badly unbalanced merges on unlucky input sizes.  It
slightly increases the code size, but saves an average of 0.2*n calls to
cmp().

x86-64 code size 739 -> 803 bytes (+64)

Unfortunately, there's not a lot of low-hanging fruit in a merge sort;
it already performs only n*log2(n) - K*n + O(1) compares.  The leading
coefficient is already at the theoretical limit (log2(n!) corresponds to
K=1.4427), so we're fighting over the linear term, and the best
mergesort can do is K=1.2645, achieved when n is a power of 2.

The differences between mergesort variants appear when n is *not* a
power of 2; K is a function of the fractional part of log2(n).  Top-down
mergesort does best of all, achieving a minimum K=1.2408, and an average
(over all sizes) K=1.248.  However, that requires knowing the number of
entries to be sorted ahead of time, and making a full pass over the
input to count it conflicts with a second performance goal, which is
cache blocking.

Obviously, we have to read the entire list into L1 cache at some point,
and performance is best if it fits.  But if it doesn't fit, each full
pass over the input causes a cache miss per element, which is
undesirable.

While textbooks explain bottom-up mergesort as a succession of merging
passes, practical implementations do merging in depth-first order: as
soon as two lists of the same size are available, they are merged.  This
allows as many merge passes as possible to fit into L1; only the final
few merges force cache misses.

This cache-friendly depth-first merge order depends on us merging the
beginning of the input as much as possible before we've even seen the
end of the input (and thus know its size).

The simple eager merge pattern causes bad performance when n is just
over a power of 2.  If n=1028, the final merge is between 1024- and
4-element lists, which is wasteful of comparisons.  (This is actually
worse on average than n=1025, because a 1204:1 merge will, on average,
end after 512 compares, while 1024:4 will walk 4/5 of the list.)

Because of this, bottom-up mergesort achieves K < 0.5 for such sizes,
and has an average (over all sizes) K of around 1.  (My experiments show
K=1.01, while theory predicts K=0.965.)

There are "worst-case optimal" variants of bottom-up mergesort which
avoid this bad performance, but the algorithms given in the literature,
such as queue-mergesort and boustrodephonic mergesort, depend on the
breadth-first multi-pass structure that we are trying to avoid.

This implementation is as eager as possible while ensuring that all
merge passes are at worst 1:2 unbalanced.  This achieves the same
average K=1.207 as queue-mergesort, which is 0.2*n better then
bottom-up, and only 0.04*n behind top-down mergesort.

Specifically, defers merging two lists of size 2^k until it is known
that there are 2^k additional inputs following.  This ensures that the
final uneven merges triggered by reaching the end of the input will be
at worst 2:1.  This will avoid cache misses as long as 3*2^k elements
fit into the cache.

(I confess to being more than a little bit proud of how clean this code
turned out.  It took a lot of thinking, but the resultant inner loop is
very simple and efficient.)

Refs:
  Bottom-up Mergesort: A Detailed Analysis
  Wolfgang Panny, Helmut Prodinger
  Algorithmica 14(4):340--354, October 1995
  https://doi.org/10.1007/BF01294131
  https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.6.5260

  The cost distribution of queue-mergesort, optimal mergesorts, and
  power-of-two rules
  Wei-Mei Chen, Hsien-Kuei Hwang, Gen-Huey Chen
  Journal of Algorithms 30(2); Pages 423--448, February 1999
  https://doi.org/10.1006/jagm.1998.0986
  https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.5380

  Queue-Mergesort
  Mordecai J. Golin, Robert Sedgewick
  Information Processing Letters, 48(5):253--259, 10 December 1993
  https://doi.org/10.1016/0020-0190(93)90088-q
  https://sci-hub.tw/10.1016/0020-0190(93)90088-Q

Feedback from Rasmus Villemoes <linux@rasmusvillemoes.dk>.

Link: http://lkml.kernel.org/r/fd560853cc4dca0d0f02184ffa888b4c1be89abc.1552704200.git.lkml@sdf.org
Signed-off-by: George Spelvin <lkml@sdf.org>
Acked-by: Andrey Abramov <st5pub@yandex.ru>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Wagner <daniel.wagner@siemens.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Don Mullis <don.mullis@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
George Spelvin 043b3f7b63 lib/list_sort: simplify and remove MAX_LIST_LENGTH_BITS
Rather than a fixed-size array of pending sorted runs, use the ->prev
links to keep track of things.  This reduces stack usage, eliminates
some ugly overflow handling, and reduces the code size.

Also:
* merge() no longer needs to handle NULL inputs, so simplify.
* The same applies to merge_and_restore_back_links(), which is renamed
  to the less ponderous merge_final().  (It's a static helper function,
  so we don't need a super-descriptive name; comments will do.)
* Document the actual return value requirements on the (*cmp)()
  function; some callers are already using this feature.

x86-64 code size 1086 -> 739 bytes (-347)

(Yes, I see checkpatch complaining about no space after comma in
"__attribute__((nonnull(2,3,4,5)))".  Checkpatch is wrong.)

Feedback from Rasmus Villemoes, Andy Shevchenko and Geert Uytterhoeven.

[akpm@linux-foundation.org: remove __pure usage due to mysterious warning]
Link: http://lkml.kernel.org/r/f63c410e0ff76009c9b58e01027e751ff7fdb749.1552704200.git.lkml@sdf.org
Signed-off-by: George Spelvin <lkml@sdf.org>
Acked-by: Andrey Abramov <st5pub@yandex.ru>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Daniel Wagner <daniel.wagner@siemens.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Don Mullis <don.mullis@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00
George Spelvin 8fb583c425 lib/sort: avoid indirect calls to built-in swap
Similar to what's being done in the net code, this takes advantage of
the fact that most invocations use only a few common swap functions, and
replaces indirect calls to them with (highly predictable) conditional
branches.  (The downside, of course, is that if you *do* use a custom
swap function, there are a few extra predicted branches on the code
path.)

This actually *shrinks* the x86-64 code, because it inlines the various
swap functions inside do_swap, eliding function prologues & epilogues.

x86-64 code size 767 -> 703 bytes (-64)

Link: http://lkml.kernel.org/r/d10c5d4b393a1847f32f5b26f4bbaa2857140e1e.1552704200.git.lkml@sdf.org
Signed-off-by: George Spelvin <lkml@sdf.org>
Acked-by: Andrey Abramov <st5pub@yandex.ru>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Wagner <daniel.wagner@siemens.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Don Mullis <don.mullis@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:49 -07:00