Merge branch 'rework/console-list-lock' into for-linus

1 files changed, 25 insertions, 5 deletions

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 3b89c64bcfd8..2ba557e067fe 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -248,6 +248,25 @@ static inline unsigned long __ffs64(u64 word)
 }
 
 /**
+ * fns - find N'th set bit in a word
+ * @word: The word to search
+ * @n: Bit to find
+ */
+static inline unsigned long fns(unsigned long word, unsigned int n)
+{
+	unsigned int bit;
+
+	while (word) {
+		bit = __ffs(word);
+		if (n-- == 0)
+			return bit;
+		__clear_bit(bit, &word);
+	}
+
+	return BITS_PER_LONG;
+}
+
+/**
  * assign_bit - Assign value to a bit in memory
  * @nr: the bit to set
  * @addr: the address to start counting from
@@ -328,10 +347,10 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
 	const typeof(*(ptr)) mask__ = (mask), bits__ = (bits);	\
 	typeof(*(ptr)) old__, new__;				\
 								\
+	old__ = READ_ONCE(*(ptr));				\
 	do {							\
-		old__ = READ_ONCE(*(ptr));			\
 		new__ = (old__ & ~mask__) | bits__;		\
-	} while (cmpxchg(ptr, old__, new__) != old__);		\
+	} while (!try_cmpxchg(ptr, &old__, new__));		\
 								\
 	old__;							\
 })
@@ -343,11 +362,12 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
 	const typeof(*(ptr)) clear__ = (clear), test__ = (test);\
 	typeof(*(ptr)) old__, new__;				\
 								\
+	old__ = READ_ONCE(*(ptr));				\
 	do {							\
-		old__ = READ_ONCE(*(ptr));			\
+		if (old__ & test__)				\
+			break;					\
 		new__ = old__ & ~clear__;			\
-	} while (!(old__ & test__) &&				\
-		 cmpxchg(ptr, old__, new__) != old__);		\
+	} while (!try_cmpxchg(ptr, &old__, new__));		\
 								\
 	!(old__ & test__);					\
 })