The patch titled
Subject: mips: implement xor_unlock_is_negative_byte
has been added to the -mm mm-unstable branch. Its filename is
mips-implement-xor_unlock_is_negative_byte.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mips-implement-xor_unlock_is_negative_byte.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mips: implement xor_unlock_is_negative_byte
Date: Wed, 4 Oct 2023 17:53:10 +0100
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@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Richard Henderson <richard.henderson@xxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/mips/include/asm/bitops.h | 26 +++++++++++++++++++++++++-
arch/mips/lib/bitops.c | 14 ++++++++++++++
2 files changed, 39 insertions(+), 1 deletion(-)
--- a/arch/mips/include/asm/bitops.h~mips-implement-xor_unlock_is_negative_byte
+++ a/arch/mips/include/asm/bitops.h
@@ -73,7 +73,8 @@ int __mips_test_and_clear_bit(unsigned l
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(un
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
--- a/arch/mips/lib/bitops.c~mips-implement-xor_unlock_is_negative_byte
+++ a/arch/mips/lib/bitops.c
@@ -146,3 +146,17 @@ int __mips_test_and_change_bit(unsigned
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;
+}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-make-lock_folio_maybe_drop_mmap-vma-lock-aware.patch
mm-call-wp_page_copy-under-the-vma-lock.patch
mm-handle-shared-faults-under-the-vma-lock.patch
mm-handle-cow-faults-under-the-vma-lock.patch
mm-handle-read-faults-under-the-vma-lock.patch
mm-handle-write-faults-to-ro-pages-under-the-vma-lock.patch
iomap-hold-state_lock-over-call-to-ifs_set_range_uptodate.patch
iomap-protect-read_bytes_pending-with-the-state_lock.patch
mm-add-folio_end_read.patch
ext4-use-folio_end_read.patch
buffer-use-folio_end_read.patch
iomap-use-folio_end_read.patch
bitops-add-xor_unlock_is_negative_byte.patch
alpha-implement-xor_unlock_is_negative_byte.patch
m68k-implement-xor_unlock_is_negative_byte.patch
mips-implement-xor_unlock_is_negative_byte.patch
powerpc-implement-arch_xor_unlock_is_negative_byte-on-32-bit.patch
riscv-implement-xor_unlock_is_negative_byte.patch
s390-implement-arch_xor_unlock_is_negative_byte.patch
mm-delete-checks-for-xor_unlock_is_negative_byte.patch
mm-add-folio_xor_flags_has_waiters.patch
mm-make-__end_folio_writeback-return-void.patch
mm-use-folio_xor_flags_has_waiters-in-folio_end_writeback.patch
