Hi all, Whilst investigating a livelock in fs/dcache.c [1], I noticed that the arm64 test_and_set operation always writes back to memory even if the value is already set. This led me to start hacking on improved versions of our bitops, including an acquire version of test_and_set_bit_lock.
Since there was nothing arm64-specific about the resulting code, I figured I'd replace what's sitting in asm-generic/bitops/atomic.h and simply include that instead. I had to rejig a couple of #includes so that I can call into atomic_* ops from bitops.h, but that was actually pretty straightforward. Feedback welcome, Will [1] https://lkml.org/lkml/2018/2/13/414 --->8 Will Deacon (5): arm64: fpsimd: include <linux/init.h> in fpsimd.h asm-generic: Avoid including linux/kernel.h in asm-generic/bug.h asm-generic/bitops/atomic.h: Rewrite using atomic_fetch_* arm64: Replace our atomic bitops implementation with asm-generic arm64: bitops: Include <asm-generic/bitops/ext2-atomic-setbit.h> arch/arm64/include/asm/bitops.h | 20 +--- arch/arm64/include/asm/fpsimd.h | 1 + arch/arm64/lib/Makefile | 2 +- arch/arm64/lib/bitops.S | 76 ------------- include/asm-generic/bitops/atomic.h | 219 ++++++++++++------------------------ include/asm-generic/bug.h | 2 +- lib/errseq.c | 1 + 7 files changed, 77 insertions(+), 244 deletions(-) delete mode 100644 arch/arm64/lib/bitops.S -- 2.1.4
