These arguments are always passed as 0, and they are never evaluated.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

In gfs2_rgrp_verify and compute_bitstructs, make sure to report errors before
withdrawing the filesystem: otherwise, when we withdraw first and withdraw is
configured to panic, we'll never get to the error reporting.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

Split gfs2_lm_withdraw into a function that prints an error message and a
function that withdraws the filesystem.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

In gfs2_file_write_iter, for direct writes, the error checking in the buffered
write fallback case is incomplete.  This can cause inode write errors to go
undetected.  Fix and clean up gfs2_file_write_iter along the way.

Based on a proposed fix by Christoph Hellwig <hch@lst.de>.

Fixes: 967bcc91 ("gfs2: iomap direct I/O support")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Set current->backing_dev_info just around the buffered write calls to
prepare for the next fix.

Fixes: 967bcc91 ("gfs2: iomap direct I/O support")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

When the first log header in a journal happens to have a sequence
number of 0, a bug in gfs2_find_jhead() causes it to prematurely exit,
and return an uninitialized jhead with seq 0. This can cause failures
in the caller. For instance, a mount fails in one test case.

The correct behavior is for it to continue searching through the journal
to find the correct journal head with the highest sequence number.

Fixes: f4686c26 ("gfs2: read journal in large chunks")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Pull gfs2 updates from Andreas Gruenbacher:

 - Fix some corner cases on filesystems with a block size < page size.

 - Fix a corner case that could expose incorrect access times over nfs.

 - Revert an otherwise sensible revoke accounting cleanup that causes
   assertion failures. The revoke accounting is whacky and needs to be
   fixed properly before we can add back this cleanup.

 - Various other minor cleanups.

In addition, please expect to see another pull request from Bob Peterson
about his gfs2 recovery patch queue shortly.

* tag 'gfs2-for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  Revert "gfs2: eliminate tr_num_revoke_rm"
  gfs2: remove unused LBIT macros
  fs/gfs2: remove unused IS_DINODE and IS_LEAF macros
  gfs2: Remove GFS2_MIN_LVB_SIZE define
  gfs2: Fix incorrect variable name
  gfs2: Avoid access time thrashing in gfs2_inode_lookup
  gfs2: minor cleanup: remove unneeded variable ret in gfs2_jdata_writepage
  gfs2: eliminate ssize parameter from gfs2_struct2blk
  gfs2: Another gfs2_find_jhead fix

Pull iomap fix from Darrick Wong:
 "A single patch fixing an off-by-one error when we're checking to see
  how far we're gotten into an EOF page"

* tag 'iomap-5.6-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  fs: Fix page_mkwrite off-by-one errors

Pull updates from Andrew Morton:
 "Most of -mm and quite a number of other subsystems: hotfixes, scripts,
  ocfs2, misc, lib, binfmt, init, reiserfs, exec, dma-mapping, kcov.

  MM is fairly quiet this time.  Holidays, I assume"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits)
  kcov: ignore fault-inject and stacktrace
  include/linux/io-mapping.h-mapping: use PHYS_PFN() macro in io_mapping_map_atomic_wc()
  execve: warn if process starts with executable stack
  reiserfs: prevent NULL pointer dereference in reiserfs_insert_item()
  init/main.c: fix misleading "This architecture does not have kernel memory protection" message
  init/main.c: fix quoted value handling in unknown_bootoption
  init/main.c: remove unnecessary repair_env_string in do_initcall_level
  init/main.c: log arguments and environment passed to init
  fs/binfmt_elf.c: coredump: allow process with empty address space to coredump
  fs/binfmt_elf.c: coredump: delete duplicated overflow check
  fs/binfmt_elf.c: coredump: allocate core ELF header on stack
  fs/binfmt_elf.c: make BAD_ADDR() unlikely
  fs/binfmt_elf.c: better codegen around current->mm
  fs/binfmt_elf.c: don't copy ELF header around
  fs/binfmt_elf.c: fix ->start_code calculation
  fs/binfmt_elf.c: smaller code generation around auxv vector fill
  lib/find_bit.c: uninline helper _find_next_bit()
  lib/find_bit.c: join _find_next_bit{_le}
  uapi: rename ext2_swab() to swab() and share globally in swab.h
  lib/scatterlist.c: adjust indentation in __sg_alloc_table
  ...

Pull module updates from Jessica Yu:
 "Summary of modules changes for the 5.6 merge window:

   - Add "MS" (SHF_MERGE|SHF_STRINGS) section flags to __ksymtab_strings
     to indicate to the linker that it can perform string deduplication
     (i.e., duplicate strings are reduced to a single copy in the string
     table). This means any repeated namespace string would be merged to
     just one entry in __ksymtab_strings.

   - Various code cleanups and small fixes (fix small memleak in error
     path, improve moduleparam docs, silence rcu warnings, improve error
     logging)"

* tag 'modules-for-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module.h: Annotate mod_kallsyms with __rcu
  module: avoid setting info->name early in case we can fall back to info->mod->name
  modsign: print module name along with error message
  kernel/module: Fix memleak in module_add_modinfo_attrs()
  export.h: reduce __ksymtab_strings string duplication by using "MS" section flags
  moduleparam: fix kerneldoc
  modules: lockdep: Suppress suspicious RCU usage warning

Pull MIPS changes from Paul Burton:
 "Nothing too big or scary in here:

   - Support mremap() for the VDSO, primarily to allow CRIU to restore
     the VDSO to its checkpointed location.

   - Restore the MIPS32 cBPF JIT, after having reverted the enablement
     of the eBPF JIT for MIPS32 systems in the 5.5 cycle.

   - Improve cop0 counter synchronization behaviour whilst onlining CPUs
     by running with interrupts disabled.

   - Better match FPU behaviour when emulating multiply-accumulate
     instructions on pre-r6 systems that implement IEEE754-2008 style
     MACs.

   - Loongson64 kernels now build using the MIPS64r2 ISA, allowing them
     to take advantage of instructions introduced by r2.

   - Support for the Ingenic X1000 SoC & the really nice little CU Neo
     development board that's using it.

   - Support for WMAC on GARDENA Smart Gateway devices.

   - Lots of cleanup & refactoring of SGI IP27 (Origin 2*) support in
     preparation for introducing IP35 (Origin 3*) support.

   - Various Kconfig & Makefile cleanups"

* tag 'mips_5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (60 commits)
  MIPS: PCI: Add detection of IOC3 on IO7, IO8, IO9 and Fuel
  MIPS: Loongson64: Disable exec hazard
  MIPS: Loongson64: Bump ISA level to MIPSR2
  MIPS: Make DIEI support as a config option
  MIPS: OCTEON: octeon-irq: fix spelling mistake "to" -> "too"
  MIPS: asm: local: add barriers for Loongson
  MIPS: Loongson64: Select mac2008 only feature
  MIPS: Add MAC2008 Support
  Revert "MIPS: Add custom serial.h with BASE_BAUD override for generic kernel"
  MIPS: sort MIPS and MIPS_GENERIC Kconfig selects alphabetically (again)
  MIPS: make CPU_HAS_LOAD_STORE_LR opt-out
  MIPS: generic: don't unconditionally select PINCTRL
  MIPS: don't explicitly select LIBFDT in Kconfig
  MIPS: sync-r4k: do slave counter synchronization with disabled HW interrupts
  MIPS: SGI-IP30: Check for valid pointer before using it
  MIPS: syscalls: fix indentation of the 'SYSNR' message
  MIPS: boot: fix typo in 'vmlinux.lzma.its' target
  MIPS: fix indentation of the 'RELOCS' message
  dt-bindings: Document loongson vendor-prefix
  MIPS: CU1000-Neo: Refresh defconfig to support HWMON and WiFi.
  ...

Pull ARC updates from Vineet Gupta:

 - Wire up clone3 syscall

 - ARCv2 FPU state save/restore across context switch

 - AXS10x platform and misc fixes

* tag 'arc-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARCv2: fpu: preserve userspace fpu state
  ARC: fpu: declutter code, move bits out into fpu.h
  ARC: wireup clone3 syscall
  ARC: [plat-axs10x]: Add missing multicast filter number to GMAC node
  ARC: update feature support for jump-labels

Pull RISC-V updates from Palmer Dabbelt:
 "This contains a handful of patches for this merge window:

   - Support for kasan

   - 32-bit physical addresses on rv32i-based systems

   - Support for CONFIG_DEBUG_VIRTUAL

   - DT entry for the FU540 GPIO controller, which has recently had a
     device driver merged

  These boot a buildroot-based system on QEMU's virt board for me"

* tag 'riscv-for-linus-5.6-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: dts: Add DT support for SiFive FU540 GPIO driver
  riscv: mm: add support for CONFIG_DEBUG_VIRTUAL
  riscv: keep 32-bit kernel to 32-bit phys_addr_t
  kasan: Add riscv to KASAN documentation.
  riscv: Add KASAN support
  kasan: No KASAN's memmove check if archs don't have it.

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - three fixes and a cleanup for the resctrl code

   - a HyperV fix

   - a fix to /proc/kcore contents in live debugging sessions

   - a fix for the x86 decoder opcode map"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/decoder: Add TEST opcode to Group3-2
  x86/resctrl: Clean up unused function parameter in mkdir path
  x86/resctrl: Fix a deadlock due to inaccurate reference
  x86/resctrl: Fix use-after-free due to inaccurate refcount of rdtgroup
  x86/resctrl: Fix use-after-free when deleting resource groups
  x86/hyper-v: Add "polling" bit to hv_synic_sint
  x86/crash: Define arch_crash_save_vmcoreinfo() if CONFIG_CRASH_CORE=y

Don't instrument 3 more files that contain debugging facilities and
produce large amounts of uninteresting coverage for every syscall.

The following snippets are sprinkled all over the place in kcov traces
in a debugging kernel.  We already try to disable instrumentation of
stack unwinding code and of most debug facilities.  I guess we did not
use fault-inject.c at the time, and stacktrace.c was somehow missed (or
something has changed in kernel/configs).  This change both speeds up
kcov (kernel doesn't need to store these PCs, user-space doesn't need to
process them) and frees trace buffer capacity for more useful coverage.

  should_fail
  lib/fault-inject.c:149
  fail_dump
  lib/fault-inject.c:45

  stack_trace_save
  kernel/stacktrace.c:124
  stack_trace_consume_entry
  kernel/stacktrace.c:86
  stack_trace_consume_entry
  kernel/stacktrace.c:89
  ... a hundred frames skipped ...
  stack_trace_consume_entry
  kernel/stacktrace.c:93
  stack_trace_consume_entry
  kernel/stacktrace.c:86

Link: http://lkml.kernel.org/r/20200116111449.217744-1-dvyukov@gmail.comSigned-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Use PHYS_PFN() macro in io_mapping_map_atomic_wc() instead of open coded
variant.

Link: http://lkml.kernel.org/r/20191209165624.56351-1-andriy.shevchenko@linux.intel.comSigned-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There were few episodes of silent downgrade to an executable stack over
years:

1) linking innocent looking assembly file will silently add executable
   stack if proper linker options is not given as well:

	$ cat f.S
	.intel_syntax noprefix
	.text
	.globl f
	f:
	        ret

	$ cat main.c
	void f(void);
	int main(void)
	{
	        f();
	        return 0;
	}

	$ gcc main.c f.S
	$ readelf -l ./a.out
	  GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
                         0x0000000000000000 0x0000000000000000  RWE    0x10
			 					 ^^^

2) converting C99 nested function into a closure
   https://nullprogram.com/blog/2019/11/15/

	void intsort2(int *base, size_t nmemb, _Bool invert)
	{
	    int cmp(const void *a, const void *b)
	    {
	        int r = *(int *)a - *(int *)b;
	        return invert ? -r : r;
	    }
	    qsort(base, nmemb, sizeof(*base), cmp);
	}

will silently require stack trampolines while non-closure version will
not.

Without doubt this behaviour is documented somewhere, add a warning so
that developers and users can at least notice.  After so many years of
x86_64 having proper executable stack support it should not cause too
many problems.

Link: http://lkml.kernel.org/r/20191208171918.GC19716@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Will Deacon <will@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The variable inode may be NULL in reiserfs_insert_item(), but there is
no check before accessing the member of inode.

Fix this by adding NULL pointer check before calling reiserfs_debug().

Link: http://lkml.kernel.org/r/79c5135d-ff25-1cc9-4e99-9f572b88cc00@huawei.comSigned-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Cc: zhengbin <zhengbin13@huawei.com>
Cc: Hu Shiyuan <hushiyuan@huawei.com>
Cc: Feilong Lin <linfeilong@huawei.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This message leads to thinking that memory protection is not implemented
for the said architecture, whereas absence of CONFIG_STRICT_KERNEL_RWX
only means that memory protection has not been selected at compile time.

Don't print this message when CONFIG_ARCH_HAS_STRICT_KERNEL_RWX is
selected by the architecture.  Instead, print "Kernel memory protection
not selected by kernel config."

Link: http://lkml.kernel.org/r/62477e446d9685459d4f27d193af6ff1bd69d55f.1578557581.git.christophe.leroy@c-s.frSigned-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "init/main.c: minor cleanup/bugfix of envvar handling", v2.

unknown_bootoption passes unrecognized command line arguments to init as
either environment variables or arguments.  Some of the logic in the
function is broken for quoted command line arguments.

When an argument of the form param="value" is processed by parse_args
and passed to unknown_bootoption, the command line has

  param\0"value\0

with val pointing to the beginning of value.  The helper function
repair_env_string is then used to restore the '=' character that was
removed by parse_args, and strip the quotes off fully.  This results in

  param=value\0\0

and val ends up pointing to the 'a' instead of the 'v' in value.  This
bug was introduced when repair_env_string was refactored into a separate
function, and the decrement of val in repair_env_string became dead
code.

This causes two problems in unknown_bootoption in the two places where
the val pointer is used as a substitute for the length of param:

1. An argument of the form param=".value" is misinterpreted as a
   potential module parameter, with the result that it will not be
   placed in init's environment.

2. An argument of the form param="value" is checked to see if param is
   an existing environment variable that should be overwritten, but the
   comparison is off-by-one and compares 'param=v' instead of 'param='
   against the existing environment. So passing, for example,
   TERM="vt100" on the command line results in init being passed both
   TERM=linux and TERM=vt100 in its environment.

Patch 1 adds logging for the arguments and environment passed to init
and is independent of the rest: it can be dropped if this is
unnecessarily verbose.

Patch 2 removes repair_env_string from initcall parameter parsing in
do_initcall_level, as that uses a separate copy of the command line now
and the repairing is no longer necessary.

Patch 3 fixes the bug in unknown_bootoption by recording the length of
param explicitly instead of implying it from val-param.

This patch (of 3):

Commit a99cd112 ("init: fix bug where environment vars can't be
passed via boot args") introduced two minor bugs in unknown_bootoption
by factoring out the quoted value handling into a separate function.

When value is quoted, repair_env_string will move the value up 1 byte to
strip the quotes, so val in unknown_bootoption no longer points to the
actual location of the value.

The result is that an argument of the form param=".value" is mistakenly
treated as a potential module parameter and is not placed in init's
environment, and an argument of the form param="value" can result in a
duplicate environment variable: eg TERM="vt100" on the command line will
result in both TERM=linux and TERM=vt100 being placed into init's
environment.

Fix this by recording the length of the param before calling
repair_env_string instead of relying on val.

Link: http://lkml.kernel.org/r/20191212180023.24339-4-nivedita@alum.mit.eduSigned-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Since commit 08746a65 ("init: fix in-place parameter modification
regression"), parse_args in do_initcall_level is called on a copy of
saved_command_line.  It is unnecessary to call repair_env_string during
this parsing, as this copy is not used for anything later.

Remove the now unnecessary arguments from repair_env_string as well.

Link: http://lkml.kernel.org/r/20191212180023.24339-3-nivedita@alum.mit.eduSigned-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Krzysztof Mazur <krzysiek@podlesie.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Extend logging in `run_init_process` to also show the arguments and
environment that we are passing to init.

Link: http://lkml.kernel.org/r/20191212180023.24339-2-nivedita@alum.mit.eduSigned-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Unmapping whole address space at once with

	munmap(0, (1ULL<<47) - 4096)

or equivalent will create empty coredump.

It is silly way to exit, however registers content may still be useful.

The right to coredump is fundamental right of a process!

Link: http://lkml.kernel.org/r/20191222150137.GA1277@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

array_size() macro will do overflow check anyway.

Link: http://lkml.kernel.org/r/20191222144009.GB24341@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Comment says ELF header is "too large to be on stack".  64 bytes on
64-bit is not large by any means.

Link: http://lkml.kernel.org/r/20191222143850.GA24341@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If some mapping goes past TASK_SIZE it will be rejected by kernel which
means no such userspace binaries exist.

Mark every such check as unlikely.

Link: http://lkml.kernel.org/r/20191215124355.GA21124@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

"current->mm" pointer is stable in general except few cases one of which
execve(2).  Compiler can't treat is as stable but it _is_ stable most of
the time.  During ELF loading process ->mm becomes stable right after
flush_old_exec().

Help compiler by caching current->mm, otherwise it continues to refetch
it.

	add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-141 (-141)
	Function                                     old     new   delta
	elf_core_dump                               5062    5039     -23
	load_elf_binary                             5426    5308    -118

Note: other cases are left as is because it is either pessimisation or
no change in binary size.

Link: http://lkml.kernel.org/r/20191215124755.GB21124@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ELF header is read into bprm->buf[] by generic execve code.

Save a memcpy and allocate just one header for the interpreter instead
of two headers (64 bytes instead of 128 on 64-bit).

Link: http://lkml.kernel.org/r/20191208171242.GA19716@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Only executable segments should be accounted to ->start_code just like
they do to ->end_code (correctly).

Link: http://lkml.kernel.org/r/20191208171410.GB19716@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Filling auxv vector as array with index (auxv[i++] = ...) generates
terrible code.  "saved_auxv" should be reworked because it is the worst
member of mm_struct by size/usefullness ratio but do it later.

Meanwhile help gcc a little with *auxv++ idiom.

Space savings on x86_64:

	add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-127 (-127)
	Function                                     old     new   delta
	load_elf_binary                             5470    5343    -127

Link: http://lkml.kernel.org/r/20191208172301.GD19716@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It saves 25% of .text for arm64, and more for BE architectures.

Before:
  $ size lib/find_bit.o
     text    data     bss     dec     hex filename
     1012      56       0    1068     42c lib/find_bit.o

After:
  $ size lib/find_bit.o
     text    data     bss     dec     hex filename
      776      56       0     832     340 lib/find_bit.o

Link: http://lkml.kernel.org/r/20200103202846.21616-3-yury.norov@gmail.comSigned-off-by: Yury Norov <yury.norov@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Allison Randal <allison@lohutok.net>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

_find_next_bit and _find_next_bit_le are very similar functions.  It's
possible to join them by adding 1 parameter and a couple of simple
checks.  It's simplify maintenance and make possible to shrink the size
of .text by un-inlining the unified function (in the following patch).

Link: http://lkml.kernel.org/r/20200103202846.21616-2-yury.norov@gmail.comSigned-off-by: Yury Norov <yury.norov@gmail.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Joe Perches <joe@perches.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ext2_swab() is defined locally in lib/find_bit.c However it is not
specific to ext2, neither to bitmaps.

There are many potential users of it, so rename it to just swab() and
move to include/uapi/linux/swab.h

ABI guarantees that size of unsigned long corresponds to BITS_PER_LONG,
therefore drop unneeded cast.

Link: http://lkml.kernel.org/r/20200103202846.21616-1-yury.norov@gmail.comSigned-off-by: Yury Norov <yury.norov@gmail.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Joe Perches <joe@perches.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Clang warns:

  ../lib/scatterlist.c:314:5: warning: misleading indentation; statement
  is not part of the previous 'if' [-Wmisleading-indentation]
                          return -ENOMEM;
                          ^
  ../lib/scatterlist.c:311:4: note: previous statement is here
                          if (prv)
                          ^
  1 warning generated.

This warning occurs because there is a space before the tab on this
line.  Remove it so that the indentation is consistent with the Linux
kernel coding style and clang no longer warns.

Link: http://lkml.kernel.org/r/20191218033606.11942-1-natechancellor@gmail.com
Link: https://github.com/ClangBuiltLinux/linux/issues/830
Fixes: edce6820 ("scatterlist: prevent invalid free when alloc fails")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In order to benefit from s390 zlib hardware compression support,
increase the btrfs zlib workspace buffer size from 1 to 4 pages (if s390
zlib hardware support is enabled on the machine).

This brings up to 60% better performance in hardware on s390 compared to
the PAGE_SIZE buffer and much more compared to the software zlib
processing in btrfs.  In case of memory pressure, fall back to a single
page buffer during workspace allocation.

The data compressed with larger input buffers will still conform to zlib
standard and thus can be decompressed also on a systems that uses only
PAGE_SIZE buffer for btrfs zlib.

Link: http://lkml.kernel.org/r/20200108105103.29028-1-zaslonko@linux.ibm.comSigned-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add a new function to zlib.h checking if s390 Deflate-Conversion
facility is installed and enabled.

Link: http://lkml.kernel.org/r/20200103223334.20669-6-zaslonko@linux.ibm.comSigned-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add the new kernel command line parameter 'dfltcc=' to configure s390
zlib hardware support.

Format: { on | off | def_only | inf_only | always }
 on:       s390 zlib hardware support for compression on
           level 1 and decompression (default)
 off:      No s390 zlib hardware support
 def_only: s390 zlib hardware support for deflate
           only (compression on level 1)
 inf_only: s390 zlib hardware support for inflate
           only (decompression)
 always:   Same as 'on' but ignores the selected compression
           level always using hardware support (used for debugging)

Link: http://lkml.kernel.org/r/20200103223334.20669-5-zaslonko@linux.ibm.comSigned-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add decompression functions to zlib_dfltcc library.  Update zlib_inflate
functions with the hooks for s390 hardware support and adjust workspace
structures with extra parameter lists required for hardware inflate
decompression.

Link: http://lkml.kernel.org/r/20200103223334.20669-4-zaslonko@linux.ibm.comSigned-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Co-developed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change the conflicting macro name in preparation for zlib_inflate
hardware support.

Link: http://lkml.kernel.org/r/20200103223334.20669-3-zaslonko@linux.ibm.comSigned-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "S390 hardware support for kernel zlib", v3.

With IBM z15 mainframe the new DFLTCC instruction is available.  It
implements deflate algorithm in hardware (Nest Acceleration Unit - NXU)
with estimated compression and decompression performance orders of
magnitude faster than the current zlib.

This patchset adds s390 hardware compression support to kernel zlib.
The code is based on the userspace zlib implementation:

	https://github.com/madler/zlib/pull/410

The coding style is also preserved for future maintainability.  There is
only limited set of userspace zlib functions represented in kernel.
Apart from that, all the memory allocation should be performed in
advance.  Thus, the workarea structures are extended with the parameter
lists required for the DEFLATE CONVENTION CALL instruction.

Since kernel zlib itself does not support gzip headers, only Adler-32
checksum is processed (also can be produced by DFLTCC facility).  Like
it was implemented for userspace, kernel zlib will compress in hardware
on level 1, and in software on all other levels.  Decompression will
always happen in hardware (when enabled).

Two DFLTCC compression calls produce the same results only when they
both are made on machines of the same generation, and when the
respective buffers have the same offset relative to the start of the
page.  Therefore care should be taken when using hardware compression
when reproducible results are desired.  However it does always produce
the standard conform output which can be inflated anyway.

The new kernel command line parameter 'dfltcc' is introduced to
configure s390 zlib hardware support:

    Format: { on | off | def_only | inf_only | always }
     on:       s390 zlib hardware support for compression on
               level 1 and decompression (default)
     off:      No s390 zlib hardware support
     def_only: s390 zlib hardware support for deflate
               only (compression on level 1)
     inf_only: s390 zlib hardware support for inflate
               only (decompression)
     always:   Same as 'on' but ignores the selected compression
               level always using hardware support (used for debugging)

The main purpose of the integration of the NXU support into the kernel
zlib is the use of hardware deflate in btrfs filesystem with on-the-fly
compression enabled.  Apart from that, hardware support can also be used
during boot for decompressing the kernel or the ramdisk image

With the patch for btrfs expanding zlib buffer from 1 to 4 pages (patch
6) the following performance results have been achieved using the
ramdisk with btrfs.  These are relative numbers based on throughput rate
and compression ratio for zlib level 1:

  Input data              Deflate rate   Inflate rate   Compression ratio
                          NXU/Software   NXU/Software   NXU/Software
  stream of zeroes        1.46           1.02           1.00
  random ASCII data       10.44          3.00           0.96
  ASCII text (dickens)    6,21           3.33           0.94
  binary data (vmlinux)   8,37           3.90           1.02

This means that s390 hardware deflate can provide up to 10 times faster
compression (on level 1) and up to 4 times faster decompression (refers
to all compression levels) for btrfs zlib.

Disclaimer: Performance results are based on IBM internal tests using DD
command-line utility on btrfs on a Fedora 30 based internal driver in
native LPAR on a z15 system.  Results may vary based on individual
workload, configuration and software levels.

This patch (of 9):

Create zlib_dfltcc library with the s390 DEFLATE CONVERSION CALL
implementation and related compression functions.  Update zlib_deflate
functions with the hooks for s390 hardware support and adjust workspace
structures with extra parameter lists required for hardware deflate.

Link: http://lkml.kernel.org/r/20200103223334.20669-2-zaslonko@linux.ibm.comSigned-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Co-developed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>