Allow finding the first or next bit within two input bitmasks which is
either:
- both zero and zero,
- respectively one and zero.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
---
include/linux/find.h | 110 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 110 insertions(+)
diff --git a/include/linux/find.h b/include/linux/find.h
index 935892da576e..325707b8bd56 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -76,6 +76,66 @@ unsigned long find_next_and_bit(const unsigned long *addr1,
}
#endif
+#ifndef find_next_one_and_zero_bit
+/**
+ * find_next_one_and_zero_bit - find the next bit which is one in addr1 and zero in addr2 memory region
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next bit set in addr1 and cleared in addr2
+ * If no corresponding bits meet this criterion, returns @size.
+ */
+static inline
+unsigned long find_next_one_and_zero_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long size,
+ unsigned long offset)
+{
+ if (small_const_nbits(size)) {
+ unsigned long val;
+
+ if (unlikely(offset >= size))
+ return size;
+
+ val = *addr1 & ~*addr2 & GENMASK(size - 1, offset);
+ return val ? __ffs(val) : size;
+ }
+
+ return _find_next_bit(addr1, addr2, size, offset, 0UL, ~0UL, 0);
+}
+#endif
+
+#ifndef find_next_zero_and_zero_bit
+/**
+ * find_next_zero_and_zero_bit - find the next bit which is zero in addr1 and addr2 memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next bit cleared in addr1 and addr2
+ * If no corresponding bits meet this criterion, returns @size.
+ */
+static inline
+unsigned long find_next_zero_and_zero_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long size,
+ unsigned long offset)
+{
+ if (small_const_nbits(size)) {
+ unsigned long val;
+
+ if (unlikely(offset >= size))
+ return size;
+
+ val = ~*addr1 & ~*addr2 & GENMASK(size - 1, offset);
+ return val ? __ffs(val) : size;
+ }
+
+ return _find_next_bit(addr1, addr2, size, offset, ~0UL, ~0UL, 0);
+}
+#endif
+
#ifndef find_next_zero_bit
/**
* find_next_zero_bit - find the next cleared bit in a memory region
@@ -173,6 +233,56 @@ unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size)
}
#endif
+#ifndef find_first_one_and_zero_bit
+/**
+ * find_first_one_and_zero_bit - find the first bit which is one in addr1 and zero in addr2 memory region
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the first bit set in addr1 and cleared in addr2
+ * If no corresponding bits meet this criterion, returns @size.
+ */
+static inline
+unsigned long find_first_one_and_zero_bit(const unsigned long *addr1,
+ const unsigned long *addr2,
+ unsigned long size)
+{
+ if (small_const_nbits(size)) {
+ unsigned long val = *addr1 & ~*addr2 & GENMASK(size - 1, 0);
+
+ return val ? __ffs(val) : size;
+ }
+
+ return _find_next_bit(addr1, addr2, size, 0, 0UL, ~0UL, 0);
+}
+#endif
+
+#ifndef find_first_zero_and_zero_bit
+/**
+ * find_first_zero_and_zero_bit - find the first bit which is zero in addr1 and addr2 memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the first bit cleared in addr1 and addr2
+ * If no corresponding bits meet this criterion, returns @size.
+ */
+static inline
+unsigned long find_first_zero_and_zero_bit(const unsigned long *addr1,
+ const unsigned long *addr2,
+ unsigned long size)
+{
+ if (small_const_nbits(size)) {
+ unsigned long val = ~*addr1 & ~*addr2 & GENMASK(size - 1, 0);
+
+ return val ? __ffs(val) : size;
+ }
+
+ return _find_next_bit(addr1, addr2, size, 0, ~0UL, ~0UL, 0);
+}
+#endif
+
#ifndef find_last_bit
/**
* find_last_bit - find the last set bit in a memory region
--
2.25.1
