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authorValentin Schneider <vschneid@redhat.com>2022-10-03 16:34:17 +0100
committerYury Norov <yury.norov@gmail.com>2022-10-06 05:57:36 -0700
commit90d482908eedd56f01a707325aa541cf9c40f936 (patch)
tree26cec02bff42dd83de558ba1b7579185726554b0 /include/linux/find.h
parent78e5a3399421ad79fc024e6d78e2deb7809d26af (diff)
lib/find_bit: Introduce find_next_andnot_bit()
In preparation of introducing for_each_cpu_andnot(), add a variant of find_next_bit() that negate the bits in @addr2 when ANDing them with the bits in @addr1. Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Diffstat (limited to 'include/linux/find.h')
-rw-r--r--include/linux/find.h33
1 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/find.h b/include/linux/find.h
index 0cdfab9734a6..2235af19e7e1 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -12,6 +12,8 @@ unsigned long _find_next_bit(const unsigned long *addr1, unsigned long nbits,
unsigned long start);
unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long *addr2,
unsigned long nbits, unsigned long start);
+unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned long *addr2,
+ unsigned long nbits, unsigned long start);
unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits,
unsigned long start);
extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size);
@@ -91,6 +93,37 @@ unsigned long find_next_and_bit(const unsigned long *addr1,
}
#endif
+#ifndef find_next_andnot_bit
+/**
+ * find_next_andnot_bit - find the next set bit in *addr1 excluding all the bits
+ * in *addr2
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @size: The bitmap size in bits
+ * @offset: The bitnumber to start searching at
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+static inline
+unsigned long find_next_andnot_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_andnot_bit(addr1, addr2, size, offset);
+}
+#endif
+
#ifndef find_next_zero_bit
/**
* find_next_zero_bit - find the next cleared bit in a memory region