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-rw-r--r--include/asm-generic/bitops/instrumented-lock.h28
1 files changed, 13 insertions, 15 deletions
diff --git a/include/asm-generic/bitops/instrumented-lock.h b/include/asm-generic/bitops/instrumented-lock.h
index eb64bd4f11..542d3727ee 100644
--- a/include/asm-generic/bitops/instrumented-lock.h
+++ b/include/asm-generic/bitops/instrumented-lock.h
@@ -58,27 +58,25 @@ static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
return arch_test_and_set_bit_lock(nr, addr);
}
-#if defined(arch_clear_bit_unlock_is_negative_byte)
/**
- * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom
- * byte is negative, for unlock.
- * @nr: the bit to clear
- * @addr: the address to start counting from
+ * xor_unlock_is_negative_byte - XOR a single byte in memory and test if
+ * it is negative, for unlock.
+ * @mask: Change the bits which are set in this mask.
+ * @addr: The address of the word containing the byte to change.
*
+ * Changes some of bits 0-6 in the word pointed to by @addr.
* This operation is atomic and provides release barrier semantics.
+ * Used to optimise some folio operations which are commonly paired
+ * with an unlock or end of writeback. Bit 7 is used as PG_waiters to
+ * indicate whether anybody is waiting for the unlock.
*
- * This is a bit of a one-trick-pony for the filemap code, which clears
- * PG_locked and tests PG_waiters,
+ * Return: Whether the top bit of the byte is set.
*/
-static inline bool
-clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
+static inline bool xor_unlock_is_negative_byte(unsigned long mask,
+ volatile unsigned long *addr)
{
kcsan_release();
- instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long));
- return arch_clear_bit_unlock_is_negative_byte(nr, addr);
+ instrument_atomic_write(addr, sizeof(long));
+ return arch_xor_unlock_is_negative_byte(mask, addr);
}
-/* Let everybody know we have it. */
-#define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte
-#endif
-
#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */