The patch titled
Subject: alpha: implement xor_unlock_is_negative_byte
has been added to the -mm mm-unstable branch. Its filename is
alpha-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/alpha-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: alpha: implement xor_unlock_is_negative_byte
Date: Wed, 4 Oct 2023 17:53:08 +0100
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@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/alpha/include/asm/bitops.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
--- a/arch/alpha/include/asm/bitops.h~alpha-implement-xor_unlock_is_negative_byte
+++ a/arch/alpha/include/asm/bitops.h
@@ -286,6 +286,27 @@ arch___test_and_change_bit(unsigned long
#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..
_
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
