diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2023-10-04 18:53:08 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-18 23:34:16 +0200 |
| commit | e28ff5dc8cf6aec042741f1ea62089dca6a894ab (patch) | |
| tree | ee9cd4ca0837e2a4e4381cfce7105c4c64903a2e | |
| parent | bitops: add xor_unlock_is_negative_byte() (diff) | |
| download | linux-e28ff5dc8cf6aec042741f1ea62089dca6a894ab.tar.xz linux-e28ff5dc8cf6aec042741f1ea62089dca6a894ab.zip | |
alpha: implement xor_unlock_is_negative_byte
Inspired by the alpha clear_bit() and arch_atomic_add_return(), this will
surely be more efficient than the generic one defined in filemap.c.
Link: https://lkml.kernel.org/r/20231004165317.1061855-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | arch/alpha/include/asm/bitops.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/bitops.h b/arch/alpha/include/asm/bitops.h index bafb1c1f0fdc..b50ad6b83e85 100644 --- a/arch/alpha/include/asm/bitops.h +++ b/arch/alpha/include/asm/bitops.h @@ -286,6 +286,27 @@ arch___test_and_change_bit(unsigned long nr, volatile unsigned long *addr) #define arch_test_bit generic_test_bit #define arch_test_bit_acquire generic_test_bit_acquire +static inline bool xor_unlock_is_negative_byte(unsigned long mask, + volatile unsigned long *p) +{ + unsigned long temp, old; + + __asm__ __volatile__( + "1: ldl_l %0,%4\n" + " mov %0,%2\n" + " xor %0,%3,%0\n" + " stl_c %0,%1\n" + " beq %0,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (temp), "=m" (*p), "=&r" (old) + :"Ir" (mask), "m" (*p)); + + return (old & BIT(7)) != 0; +} +#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte + /* * ffz = Find First Zero in word. Undefined if no zero exists, * so code should check against ~0UL first.. |