1 files changed, 74 insertions, 60 deletions

diff --git a/tools/lib/find_bit.c b/tools/lib/find_bit.c
index 42c15f906aac..6a3dc167d30e 100644
--- a/tools/lib/find_bit.c
+++ b/tools/lib/find_bit.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* bit search implementation
  *
  * Copied from lib/find_bit.c to tools/lib/find_bit.c
@@ -11,75 +12,80 @@
  *
  * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease
  * size and improve performance, 2015.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
  */
 
 #include <linux/bitops.h>
 #include <linux/bitmap.h>
 #include <linux/kernel.h>
 
-#if !defined(find_next_bit)
-
 /*
- * This is a common helper function for find_next_bit and
- * find_next_zero_bit.  The difference is the "invert" argument, which
- * is XORed with each fetched word before searching it for one bits.
+ * Common helper for find_bit() function family
+ * @FETCH: The expression that fetches and pre-processes each word of bitmap(s)
+ * @MUNGE: The expression that post-processes a word containing found bit (may be empty)
+ * @size: The bitmap size in bits
  */
-static unsigned long _find_next_bit(const unsigned long *addr,
-		unsigned long nbits, unsigned long start, unsigned long invert)
-{
-	unsigned long tmp;
-
-	if (unlikely(start >= nbits))
-		return nbits;
-
-	tmp = addr[start / BITS_PER_LONG] ^ invert;
-
-	/* Handle 1st word. */
-	tmp &= BITMAP_FIRST_WORD_MASK(start);
-	start = round_down(start, BITS_PER_LONG);
-
-	while (!tmp) {
-		start += BITS_PER_LONG;
-		if (start >= nbits)
-			return nbits;
+#define FIND_FIRST_BIT(FETCH, MUNGE, size)					\
+({										\
+	unsigned long idx, val, sz = (size);					\
+										\
+	for (idx = 0; idx * BITS_PER_LONG < sz; idx++) {			\
+		val = (FETCH);							\
+		if (val) {							\
+			sz = min(idx * BITS_PER_LONG + __ffs(MUNGE(val)), sz);	\
+			break;							\
+		}								\
+	}									\
+										\
+	sz;									\
+})
 
-		tmp = addr[start / BITS_PER_LONG] ^ invert;
-	}
-
-	return min(start + __ffs(tmp), nbits);
-}
-#endif
+/*
+ * Common helper for find_next_bit() function family
+ * @FETCH: The expression that fetches and pre-processes each word of bitmap(s)
+ * @MUNGE: The expression that post-processes a word containing found bit (may be empty)
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ */
+#define FIND_NEXT_BIT(FETCH, MUNGE, size, start)				\
+({										\
+	unsigned long mask, idx, tmp, sz = (size), __start = (start);		\
+										\
+	if (unlikely(__start >= sz))						\
+		goto out;							\
+										\
+	mask = MUNGE(BITMAP_FIRST_WORD_MASK(__start));				\
+	idx = __start / BITS_PER_LONG;						\
+										\
+	for (tmp = (FETCH) & mask; !tmp; tmp = (FETCH)) {			\
+		if ((idx + 1) * BITS_PER_LONG >= sz)				\
+			goto out;						\
+		idx++;								\
+	}									\
+										\
+	sz = min(idx * BITS_PER_LONG + __ffs(MUNGE(tmp)), sz);			\
+out:										\
+	sz;									\
+})
 
-#ifndef find_next_bit
+#ifndef find_first_bit
 /*
- * Find the next set bit in a memory region.
+ * Find the first set bit in a memory region.
  */
-unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
-			    unsigned long offset)
+unsigned long _find_first_bit(const unsigned long *addr, unsigned long size)
 {
-	return _find_next_bit(addr, size, offset, 0UL);
+	return FIND_FIRST_BIT(addr[idx], /* nop */, size);
 }
 #endif
 
-#ifndef find_first_bit
+#ifndef find_first_and_bit
 /*
- * Find the first set bit in a memory region.
+ * Find the first set bit in two memory regions.
  */
-unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
+unsigned long _find_first_and_bit(const unsigned long *addr1,
+				  const unsigned long *addr2,
+				  unsigned long size)
 {
-	unsigned long idx;
-
-	for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
-		if (addr[idx])
-			return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size);
-	}
-
-	return size;
+	return FIND_FIRST_BIT(addr1[idx] & addr2[idx], /* nop */, size);
 }
 #endif
 
@@ -87,23 +93,31 @@ unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
 /*
  * Find the first cleared bit in a memory region.
  */
-unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size)
+unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size)
 {
-	unsigned long idx;
+	return FIND_FIRST_BIT(~addr[idx], /* nop */, size);
+}
+#endif
 
-	for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
-		if (addr[idx] != ~0UL)
-			return min(idx * BITS_PER_LONG + ffz(addr[idx]), size);
-	}
+#ifndef find_next_bit
+unsigned long _find_next_bit(const unsigned long *addr, unsigned long nbits, unsigned long start)
+{
+	return FIND_NEXT_BIT(addr[idx], /* nop */, nbits, start);
+}
+#endif
 
-	return size;
+#ifndef find_next_and_bit
+unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long *addr2,
+					unsigned long nbits, unsigned long start)
+{
+	return FIND_NEXT_BIT(addr1[idx] & addr2[idx], /* nop */, nbits, start);
 }
 #endif
 
 #ifndef find_next_zero_bit
-unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
-				 unsigned long offset)
+unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits,
+					 unsigned long start)
 {
-	return _find_next_bit(addr, size, offset, ~0UL);
+	return FIND_NEXT_BIT(~addr[idx], /* nop */, nbits, start);
 }
 #endif