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author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2023-10-04 19:53:10 +0300 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-19 00:34:17 +0300 |
commit | 8da36b26e3d8640364a9e60e0b5c3fa3f55d298b (patch) | |
tree | 5ca1eae6df34fbfac5981355c23522981a36b2b7 /arch | |
parent | ea845e3173f7552aae539aeb943cd19ebe90ba38 (diff) | |
download | linux-8da36b26e3d8640364a9e60e0b5c3fa3f55d298b.tar.xz |
mips: implement xor_unlock_is_negative_byte
Inspired by the mips test_and_change_bit(), this will surely be more
efficient than the generic one defined in filemap.c
Link: https://lkml.kernel.org/r/20231004165317.1061855-11-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>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/mips/include/asm/bitops.h | 26 | ||||
-rw-r--r-- | arch/mips/lib/bitops.c | 14 |
2 files changed, 39 insertions, 1 deletions
diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h index b4bf754f7db3..d98a05c478f4 100644 --- a/arch/mips/include/asm/bitops.h +++ b/arch/mips/include/asm/bitops.h @@ -73,7 +73,8 @@ int __mips_test_and_clear_bit(unsigned long nr, volatile unsigned long *addr); int __mips_test_and_change_bit(unsigned long nr, volatile unsigned long *addr); - +bool __mips_xor_is_negative_byte(unsigned long mask, + volatile unsigned long *addr); /* * set_bit - Atomically set a bit in memory @@ -279,6 +280,29 @@ static inline int test_and_change_bit(unsigned long nr, return res; } +static inline bool xor_unlock_is_negative_byte(unsigned long mask, + volatile unsigned long *p) +{ + unsigned long orig; + bool res; + + smp_mb__before_atomic(); + + if (!kernel_uses_llsc) { + res = __mips_xor_is_negative_byte(mask, p); + } else { + orig = __test_bit_op(*p, "%0", + "xor\t%1, %0, %3", + "ir"(mask)); + res = (orig & BIT(7)) != 0; + } + + smp_llsc_mb(); + + return res; +} +#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte + #undef __bit_op #undef __test_bit_op diff --git a/arch/mips/lib/bitops.c b/arch/mips/lib/bitops.c index 116d0bd8b2ae..00aee98e9d54 100644 --- a/arch/mips/lib/bitops.c +++ b/arch/mips/lib/bitops.c @@ -146,3 +146,17 @@ int __mips_test_and_change_bit(unsigned long nr, volatile unsigned long *addr) return res; } EXPORT_SYMBOL(__mips_test_and_change_bit); + +bool __mips_xor_is_negative_byte(unsigned long mask, + volatile unsigned long *addr) +{ + unsigned long flags; + unsigned long data; + + raw_local_irq_save(flags); + data = *addr; + *addr = data ^ mask; + raw_local_irq_restore(flags); + + return (data & BIT(7)) != 0; +} |