kernel/linux.git/lib/math, branch master

Merge tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-17T03:11:56+00:00

Pull non-MM updates from Andrew Morton: - "pid: make sub-init creation retryable" (Oleg Nesterov) Make creation of init in a new namespace more robust by clearing away some historical cruft which is no longer needed. Also some documentation fixups - "selftests/fchmodat2: Error handling and general" (Mark Brown) Fix and a cleanup for the fchmodat2() syscall selftest - "lib: polynomial: Move to math/ and clean up" (Andy Shevchenko) - "hung_task: Provide runtime reset interface for hung task detector" (Aaron Tomlin) Give administrators the ability to zero out /proc/sys/kernel/hung_task_detect_count - "tools/getdelays: use the static UAPI headers from tools/include/uapi" (Thomas Weißschuh) Teach getdelays to use the in-kernel UAPI headers rather than the system-provided ones - "watchdog/hardlockup: Improvements to hardlockup" (Mayank Rungta) Several cleanups and fixups to the hardlockup detector code and its documentation - "lib/bch: fix undefined behavior from signed left-shifts" (Josh Law) A couple of small/theoretical fixes in the bch code - "ocfs2/dlm: fix two bugs in dlm_match_regions()" (Junrui Luo) - "cleanup the RAID5 XOR library" (Christoph Hellwig) A quite far-reaching cleanup to this code. I can't do better than to quote Christoph: "The XOR library used for the RAID5 parity is a bit of a mess right now. The main file sits in crypto/ despite not being cryptography and not using the crypto API, with the generic implementations sitting in include/asm-generic and the arch implementations sitting in an asm/ header in theory. The latter doesn't work for many cases, so architectures often build the code directly into the core kernel, or create another module for the architecture code. Change this to a single module in lib/ that also contains the architecture optimizations, similar to the library work Eric Biggers has done for the CRC and crypto libraries later. After that it changes to better calling conventions that allow for smarter architecture implementations (although none is contained here yet), and uses static_call to avoid indirection function call overhead" - "lib/list_sort: Clean up list_sort() scheduling workarounds" (Kuan-Wei Chiu) Clean up this library code by removing a hacky thing which was added for UBIFS, which UBIFS doesn't actually need - "Fix bugs in extract_iter_to_sg()" (Christian Ehrhardt) Fix a few bugs in the scatterlist code, add in-kernel tests for the now-fixed bugs and fix a leak in the test itself - "kdump: Enable LUKS-encrypted dump target support in ARM64 and PowerPC" (Coiby Xu) Enable support of the LUKS-encrypted device dump target on arm64 and powerpc - "ocfs2: consolidate extent list validation into block read callbacks" (Joseph Qi) Cleanup, simplify, and make more robust ocfs2's validation of extent list fields (Kernel test robot loves mounting corrupted fs images!) * tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (127 commits) ocfs2: validate group add input before caching ocfs2: validate bg_bits during freefrag scan ocfs2: fix listxattr handling when the buffer is full doc: watchdog: fix typos etc update Sean's email address ocfs2: use get_random_u32() where appropriate ocfs2: split transactions in dio completion to avoid credit exhaustion ocfs2: remove redundant l_next_free_rec check in __ocfs2_find_path() ocfs2: validate extent block list fields during block read ocfs2: remove empty extent list check in ocfs2_dx_dir_lookup_rec() ocfs2: validate dx_root extent list fields during block read ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY ocfs2: handle invalid dinode in ocfs2_group_extend .get_maintainer.ignore: add Askar ocfs2: validate bg_list extent bounds in discontig groups checkpatch: exclude forward declarations of const structs tools/accounting: handle truncated taskstats netlink messages taskstats: set version in TGID exit notifications ocfs2/heartbeat: fix slot mapping rollback leaks on error paths arm64,ppc64le/kdump: pass dm-crypt keys to kdump kernel ...

lib/prime_numbers: drop temporary buffer in dump_primes()

2026-04-09T17:28:05+00:00

The function uses temporary buffer to convert primes bitmap into human readable format. Switch to using kunit_info("%*pbl")", and drop the buffer. Signed-off-by: Yury Norov

lib: math: polynomial: remove link to non-exist file and fix spelling

2026-03-28T04:19:39+00:00

The Baikal SoC and platform support was dropped from the kernel, remove the reference to non-exist file. While at it, fix spelling. Link: https://lkml.kernel.org/r/20260302092831.2267785-4-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Reviewed-by: Randy Dunlap Reviewed-by: Kuan-Wei Chiu Signed-off-by: Andrew Morton

lib: math: polynomial: don't use 'proxy' headers

2026-03-28T04:19:39+00:00

Update header inclusions to follow IWYU (Include What You Use) principle. Link: https://lkml.kernel.org/r/20260302092831.2267785-3-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Reviewed-by: Kuan-Wei Chiu Cc: Randy Dunlap Signed-off-by: Andrew Morton

lib: polynomial: move to math/ subfolder

2026-03-28T04:19:39+00:00

Patch series "lib: polynomial: Move to math/ and clean up", v2. While removing Baikal SoC and platform code pieces I found that this code belongs to lib/math/ rather than generic lib/. Hence the move and followed up cleanups. This patch (of 3): The algorithm behind polynomial belongs to our collection of math equations and expressions handling. Move it to math/ subfolder where others of the kind are located. Link: https://lkml.kernel.org/r/20260302092831.2267785-2-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Reviewed-by: Kuan-Wei Chiu Cc: Randy Dunlap Signed-off-by: Andrew Morton

lib: test_mul_u64_u64_div_u64(): test the 32bit code on 64bit

2025-11-20T22:03:42+00:00

There are slight differences in the mul_u64_add_u64_div_u64() code between 32bit and 64bit systems. Compile and test the 32bit version on 64bit hosts for better test coverage. Link: https://lkml.kernel.org/r/20251105201035.64043-10-david.laight.linux@gmail.com Signed-off-by: David Laight Reviewed-by: Nicolas Pitre Cc: Biju Das Cc: Borislav Betkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jens Axboe Cc: Li RongQing Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleinxer Cc: Uwe Kleine-König Signed-off-by: Andrew Morton

lib: mul_u64_u64_div_u64(): optimise the divide code

2025-11-20T22:03:42+00:00

Replace the bit by bit algorithm with one that generates 16 bits per iteration on 32bit architectures and 32 bits on 64bit ones. On my zen 5 this reduces the time for the tests (using the generic code) from ~3350ns to ~1000ns. Running the 32bit algorithm on 64bit x86 takes ~1500ns. It'll be slightly slower on a real 32bit system, mostly due to register pressure. The savings for 32bit x86 are much higher (tested in userspace). The worst case (lots of bits in the quotient) drops from ~900 clocks to ~130 (pretty much independant of the arguments). Other 32bit architectures may see better savings. It is possibly to optimise for divisors that span less than __LONG_WIDTH__/2 bits. However I suspect they don't happen that often and it doesn't remove any slow cpu divide instructions which dominate the result. Typical improvements for 64bit random divides: old new sandy bridge: 470 150 haswell: 400 144 piledriver: 960 467 I think rdpmc is very slow. zen5: 244 80 (Timing is 'rdpmc; mul_div(); rdpmc' with the multiply depending on the first rdpmc and the second rdpmc depending on the quotient.) Object code (64bit x86 test program): old 0x173 new 0x141. Link: https://lkml.kernel.org/r/20251105201035.64043-9-david.laight.linux@gmail.com Signed-off-by: David Laight Reviewed-by: Nicolas Pitre Cc: Biju Das Cc: Borislav Betkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jens Axboe Cc: Li RongQing Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleinxer Cc: Uwe Kleine-König Signed-off-by: Andrew Morton

lib: mul_u64_u64_div_u64(): optimise multiply on 32bit x86

2025-11-20T22:03:42+00:00

gcc generates horrid code for both ((u64)u32_a * u32_b) and (u64_a + u32_b). As well as the extra instructions it can generate a lot of spills to stack (including spills of constant zeros and even multiplies by constant zero). mul_u32_u32() already exists to optimise the multiply. Add a similar add_u64_32() for the addition. Disable both for clang - it generates better code without them. Move the 64x64 => 128 multiply into a static inline helper function for code clarity. No need for the a/b_hi/lo variables, the implicit casts on the function calls do the work for us. Should have minimal effect on the generated code. Use mul_u32_u32() and add_u64_u32() in the 64x64 => 128 multiply in mul_u64_add_u64_div_u64(). Link: https://lkml.kernel.org/r/20251105201035.64043-8-david.laight.linux@gmail.com Signed-off-by: David Laight Reviewed-by: Nicolas Pitre Cc: Biju Das Cc: Borislav Betkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jens Axboe Cc: Li RongQing Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleinxer Cc: Uwe Kleine-König Signed-off-by: Andrew Morton

lib: test_mul_u64_u64_div_u64(): test both generic and arch versions

2025-11-20T22:03:42+00:00

Change the #if in div64.c so that test_mul_u64_u64_div_u64.c can compile and test the generic version (including the 'long multiply') on architectures (eg amd64) that define their own copy. Test the kernel version and the locally compiled version on all arch. Output the time taken (in ns) on the 'test completed' trace. For reference, on my zen 5, the optimised version takes ~220ns and the generic version ~3350ns. Using the native multiply saves ~200ns and adding back the ilog2() 'optimisation' test adds ~50ms. Link: https://lkml.kernel.org/r/20251105201035.64043-7-david.laight.linux@gmail.com Signed-off-by: David Laight Reviewed-by: Nicolas Pitre Cc: Biju Das Cc: Borislav Betkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jens Axboe Cc: Li RongQing Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleinxer Cc: Uwe Kleine-König Signed-off-by: Andrew Morton

lib: add tests for mul_u64_u64_div_u64_roundup()

2025-11-20T22:03:42+00:00

Replicate the existing mul_u64_u64_div_u64() test cases with round up. Update the shell script that verifies the table, remove the comment markers so that it can be directly pasted into a shell. Rename the divisor from 'c' to 'd' to match mul_u64_add_u64_div_u64(). It any tests fail then fail the module load with -EINVAL. Link: https://lkml.kernel.org/r/20251105201035.64043-6-david.laight.linux@gmail.com Signed-off-by: David Laight Reviewed-by: Nicolas Pitre Cc: Biju Das Cc: Borislav Betkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jens Axboe Cc: Li RongQing Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleinxer Cc: Uwe Kleine-König Signed-off-by: Andrew Morton