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Slowackiego 173, 80-298 Gdansk - KRS 101882 - NIP 957-07-52-316 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230118_073551_517266_6323C1BC X-CRM114-Status: GOOD ( 13.24 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Hi all, The helper is tiny and there are advices we can live without it, so I want to present few arguments why it would be good to have it: 1. Code readability/simplification/number of lines: - decreases number of lines, - it often eliminates local variables, - for real examples see patches 3+. 2. Presence of similar helpers in other somehow related languages/libs: a) Rust[1]: 'replace' from std::mem module, there is also 'take' helper (__xchg(&x, 0)), which is the same as private helper in i915 - fetch_and_zero, see latest patch. b) C++ [2]: 'exchange' from utility header. If the idea is OK there are still 2 questions to answer: 1. Name of the helper, __xchg follows kernel conventions, but for me Rust names are also OK. 2. Where to put the helper: a) as in this patchset include/linux/non-atomic/xchg.h, proposed by Andy Shevchenko, b) include/linux/utils.h ? any better name? Some kind of container for simple helpers. All __xchg conversions were performed using cocci script, then manually adjusted if necessary. There is lot of places it can be used in, I have just chosen some of them. I can provide cocci script to detect others (not all), if necessary. Changes: v2: squashed all __xchg -> __arch_xchg t one patch (Arnd) v3: fixed alpha/xchg_local (lkp@intel.com) v4: adjusted indentation (Heiko) v5: added more __xchg conversions - patches 3-6, added tags [1]: https://doc.rust-lang.org/std/mem/index.html [2]: https://en.cppreference.com/w/cpp/header/utility Regards Andrzej Andrzej Hajda (7): arch: rename all internal names __xchg to __arch_xchg linux/include: add non-atomic version of xchg arch/*/uprobes: simplify arch_uretprobe_hijack_return_addr llist: simplify __llist_del_all io_uring: use __xchg if possible qed: use __xchg if possible drm/i915/gt: use __xchg instead of internal helper arch/alpha/include/asm/cmpxchg.h | 10 +++++----- arch/arc/include/asm/cmpxchg.h | 4 ++-- arch/arm/include/asm/cmpxchg.h | 7 ++++--- arch/arm/probes/uprobes/core.c | 8 ++------ arch/arm64/include/asm/cmpxchg.h | 7 +++---- arch/arm64/kernel/probes/uprobes.c | 9 ++------- arch/csky/kernel/probes/uprobes.c | 9 ++------- arch/hexagon/include/asm/cmpxchg.h | 10 +++++----- arch/ia64/include/asm/cmpxchg.h | 2 +- arch/ia64/include/uapi/asm/cmpxchg.h | 4 ++-- arch/loongarch/include/asm/cmpxchg.h | 4 ++-- arch/m68k/include/asm/cmpxchg.h | 6 +++--- arch/mips/include/asm/cmpxchg.h | 4 ++-- arch/mips/kernel/uprobes.c | 10 ++-------- arch/openrisc/include/asm/cmpxchg.h | 10 +++++----- arch/parisc/include/asm/cmpxchg.h | 4 ++-- arch/powerpc/include/asm/cmpxchg.h | 4 ++-- arch/powerpc/kernel/uprobes.c | 10 ++-------- arch/riscv/include/asm/atomic.h | 2 +- arch/riscv/include/asm/cmpxchg.h | 4 ++-- arch/riscv/kernel/probes/uprobes.c | 9 ++------- arch/s390/include/asm/cmpxchg.h | 8 ++++---- arch/s390/kernel/uprobes.c | 7 ++----- arch/sh/include/asm/cmpxchg.h | 4 ++-- arch/sparc/include/asm/cmpxchg_32.h | 4 ++-- arch/sparc/include/asm/cmpxchg_64.h | 6 +++--- arch/sparc/kernel/uprobes.c | 7 ++----- arch/xtensa/include/asm/cmpxchg.h | 4 ++-- drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 +- .../gpu/drm/i915/gt/intel_engine_heartbeat.c | 4 ++-- .../drm/i915/gt/intel_execlists_submission.c | 4 ++-- drivers/gpu/drm/i915/gt/intel_ggtt.c | 4 ++-- drivers/gpu/drm/i915/gt/intel_gsc.c | 2 +- drivers/gpu/drm/i915/gt/intel_gt.c | 4 ++-- drivers/gpu/drm/i915/gt/intel_gt_pm.c | 2 +- drivers/gpu/drm/i915/gt/intel_lrc.c | 6 +++--- drivers/gpu/drm/i915/gt/intel_migrate.c | 2 +- drivers/gpu/drm/i915/gt/intel_rc6.c | 2 +- drivers/gpu/drm/i915/gt/intel_rps.c | 2 +- drivers/gpu/drm/i915/gt/selftest_context.c | 2 +- .../drm/i915/gt/selftest_ring_submission.c | 2 +- drivers/gpu/drm/i915/gt/selftest_timeline.c | 2 +- drivers/gpu/drm/i915/gt/uc/intel_gsc_uc.c | 2 +- drivers/gpu/drm/i915/gt/uc/intel_uc.c | 2 +- drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 2 +- drivers/gpu/drm/i915/i915_utils.h | 1 + include/linux/llist.h | 6 ++---- include/linux/non-atomic/xchg.h | 19 +++++++++++++++++++ include/linux/qed/qed_chain.h | 19 +++++++------------ io_uring/io_uring.c | 7 ++----- io_uring/slist.h | 6 ++---- 51 files changed, 126 insertions(+), 155 deletions(-) create mode 100644 include/linux/non-atomic/xchg.h