The patch titled
Subject: mm: delete checks for xor_unlock_is_negative_byte()
has been added to the -mm mm-unstable branch. Its filename is
mm-delete-checks-for-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/mm-delete-checks-for-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: mm: delete checks for xor_unlock_is_negative_byte()
Date: Wed, 4 Oct 2023 17:53:14 +0100
Architectures which don't define their own use the one in
asm-generic/bitops/lock.h. Get rid of all the ifdefs around "maybe we
don't have it".
Link: https://lkml.kernel.org/r/20231004165317.1061855-15-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
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: 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 | 1
arch/m68k/include/asm/bitops.h | 1
arch/mips/include/asm/bitops.h | 1
arch/riscv/include/asm/bitops.h | 1
include/asm-generic/bitops/instrumented-lock.h | 5 --
include/asm-generic/bitops/lock.h | 1
kernel/kcsan/kcsan_test.c | 3 -
kernel/kcsan/selftest.c | 3 -
mm/filemap.c | 30 ---------------
mm/kasan/kasan_test.c | 3 -
10 files changed, 1 insertion(+), 48 deletions(-)
--- a/arch/alpha/include/asm/bitops.h~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/arch/alpha/include/asm/bitops.h
@@ -305,7 +305,6 @@ static inline bool xor_unlock_is_negativ
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,
--- a/arch/m68k/include/asm/bitops.h~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/arch/m68k/include/asm/bitops.h
@@ -339,7 +339,6 @@ static inline bool xor_unlock_is_negativ
return result;
#endif
}
-#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte
/*
* The true 68020 and more advanced processors support the "bfffo"
--- a/arch/mips/include/asm/bitops.h~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/arch/mips/include/asm/bitops.h
@@ -301,7 +301,6 @@ static inline bool xor_unlock_is_negativ
return res;
}
-#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte
#undef __bit_op
#undef __test_bit_op
--- a/arch/riscv/include/asm/bitops.h~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/arch/riscv/include/asm/bitops.h
@@ -202,7 +202,6 @@ static inline bool xor_unlock_is_negativ
: "memory");
return (res & BIT(7)) != 0;
}
-#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte
#undef __test_and_op_bit
#undef __op_bit
--- a/include/asm-generic/bitops/instrumented-lock.h~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/include/asm-generic/bitops/instrumented-lock.h
@@ -58,7 +58,6 @@ static inline bool test_and_set_bit_lock
return arch_test_and_set_bit_lock(nr, addr);
}
-#if defined(arch_xor_unlock_is_negative_byte)
/**
* xor_unlock_is_negative_byte - XOR a single byte in memory and test if
* it is negative, for unlock.
@@ -80,8 +79,4 @@ static inline bool xor_unlock_is_negativ
instrument_atomic_write(addr, sizeof(long));
return arch_xor_unlock_is_negative_byte(mask, addr);
}
-/* Let everybody know we have it. */
-#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte
-#endif
-
#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */
--- a/include/asm-generic/bitops/lock.h~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/include/asm-generic/bitops/lock.h
@@ -75,7 +75,6 @@ static inline bool arch_xor_unlock_is_ne
old = raw_atomic_long_fetch_xor_release(mask, (atomic_long_t *)p);
return !!(old & BIT(7));
}
-#define arch_xor_unlock_is_negative_byte arch_xor_unlock_is_negative_byte
#endif
#include <asm-generic/bitops/instrumented-lock.h>
--- a/kernel/kcsan/kcsan_test.c~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/kernel/kcsan/kcsan_test.c
@@ -699,12 +699,9 @@ static void test_barrier_nothreads(struc
KCSAN_EXPECT_RW_BARRIER(spin_unlock(&test_spinlock), true);
KCSAN_EXPECT_RW_BARRIER(mutex_lock(&test_mutex), false);
KCSAN_EXPECT_RW_BARRIER(mutex_unlock(&test_mutex), true);
-
-#ifdef xor_unlock_is_negative_byte
KCSAN_EXPECT_READ_BARRIER(xor_unlock_is_negative_byte(1, &test_var), true);
KCSAN_EXPECT_WRITE_BARRIER(xor_unlock_is_negative_byte(1, &test_var), true);
KCSAN_EXPECT_RW_BARRIER(xor_unlock_is_negative_byte(1, &test_var), true);
-#endif
kcsan_nestable_atomic_end();
}
--- a/kernel/kcsan/selftest.c~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/kernel/kcsan/selftest.c
@@ -227,12 +227,9 @@ static bool __init test_barrier(void)
KCSAN_CHECK_RW_BARRIER(arch_spin_unlock(&arch_spinlock));
spin_lock(&test_spinlock);
KCSAN_CHECK_RW_BARRIER(spin_unlock(&test_spinlock));
-
-#ifdef xor_unlock_is_negative_byte
KCSAN_CHECK_RW_BARRIER(xor_unlock_is_negative_byte(1, &test_var));
KCSAN_CHECK_READ_BARRIER(xor_unlock_is_negative_byte(1, &test_var));
KCSAN_CHECK_WRITE_BARRIER(xor_unlock_is_negative_byte(1, &test_var));
-#endif
kcsan_nestable_atomic_end();
return ret;
--- a/mm/filemap.c~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/mm/filemap.c
@@ -1482,34 +1482,6 @@ void folio_add_wait_queue(struct folio *
}
EXPORT_SYMBOL_GPL(folio_add_wait_queue);
-#ifdef xor_unlock_is_negative_byte
-#define clear_bit_unlock_is_negative_byte(nr, p) \
- xor_unlock_is_negative_byte(1 << nr, p)
-#endif
-
-#ifndef clear_bit_unlock_is_negative_byte
-
-/*
- * PG_waiters is the high bit in the same byte as PG_lock.
- *
- * On x86 (and on many other architectures), we can clear PG_lock and
- * test the sign bit at the same time. But if the architecture does
- * not support that special operation, we just do this all by hand
- * instead.
- *
- * The read of PG_waiters has to be after (or concurrently with) PG_locked
- * being cleared, but a memory barrier should be unnecessary since it is
- * in the same byte as PG_locked.
- */
-static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile void *mem)
-{
- clear_bit_unlock(nr, mem);
- /* smp_mb__after_atomic(); */
- return test_bit(PG_waiters, mem);
-}
-
-#endif
-
/**
* folio_unlock - Unlock a locked folio.
* @folio: The folio.
@@ -1525,7 +1497,7 @@ void folio_unlock(struct folio *folio)
BUILD_BUG_ON(PG_waiters != 7);
BUILD_BUG_ON(PG_locked > 7);
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
- if (clear_bit_unlock_is_negative_byte(PG_locked, folio_flags(folio, 0)))
+ if (xor_unlock_is_negative_byte(1 << PG_locked, folio_flags(folio, 0)))
folio_wake_bit(folio, PG_locked);
}
EXPORT_SYMBOL(folio_unlock);
--- a/mm/kasan/kasan_test.c~mm-delete-checks-for-xor_unlock_is_negative_byte
+++ a/mm/kasan/kasan_test.c
@@ -1098,12 +1098,9 @@ static void kasan_bitops_test_and_modify
KUNIT_EXPECT_KASAN_FAIL(test, test_and_change_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __test_and_change_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = test_bit(nr, addr));
-
-#if defined(xor_unlock_is_negative_byte)
if (nr < 7)
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result =
xor_unlock_is_negative_byte(1 << nr, addr));
-#endif
}
static void kasan_bitops_generic(struct kunit *test)
_
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
