Messages in this thread | | | From | Dave Martin <> | Subject | [RFC PATCH 0/6] Simplify setting thread flags to a particular value | Date | Thu, 19 Apr 2018 11:58:42 +0100 |
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There are a number of bits of code sprinkled around the kernel to set a thread flag if a certain condition is true, and clear it otherwise.
To help make those call sites terser and less cumbersome, this patch adds a new family of thread flag manipulators
update*_thread_flag([...,] flag, cond)
See patch 1 for details.
Reviewers please pay close attention to accidental conversion of set_tsk_thread_flag() to set_thread_flag() for example, and accidental inversion of conditions. I'm pretty sure neither happens, but build-testing can't pick these up.
Build-tested on x86 and the explicitly patched architectures (defconfig and multi_v7_defconfig for arm, defconfig for arm64, mips, powerpc, sparc).
Boot-tested on arm64, with some context-switch stress tests that depend on correct maintenance of TIF_FOREIGN_FPSTATE.
Background rationale:
I've found myself coding this idiom a few times now and would like to stop duplicating it. Using an ungainly lash-up of sed and grep I tried to find other users of the same idiom without too many false positives, and there while there aren't a huge number it seemed enough to be worth having a go at a simple cleanup.
The core changes are in the first patch; other changes are split per-arch.
Dave Martin (6): thread_info: Add update_thread_flag() helpers ARM: Use update_thread_flag() arm64: Use update{,_tsk}_thread_flag() MIPS: Use update{,_tsk}_thread_flag() powerpc: Use update_thread_flag() sparc: Use update_thread_flag()
arch/arm/kernel/elf.c | 9 +++------ arch/arm64/kernel/fpsimd.c | 19 +++++++------------ arch/mips/kernel/elf.c | 10 ++-------- arch/mips/kernel/process.c | 15 ++++++--------- arch/mips/kernel/ptrace.c | 5 +---- arch/mips/kernel/syscall.c | 10 ++-------- arch/powerpc/include/asm/elf.h | 10 ++-------- arch/sparc/include/asm/elf_64.h | 5 +---- include/linux/sched.h | 6 ++++++ include/linux/thread_info.h | 11 +++++++++++ include/trace/syscall.h | 6 ++---- kernel/ptrace.c | 13 +++++-------- 12 files changed, 48 insertions(+), 71 deletions(-)
-- 2.1.4
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