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-rw-r--r--lib/find_bit.c49
1 files changed, 24 insertions, 25 deletions
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 1b8e4b2a9cba..894b656f6836 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -19,6 +19,27 @@
#include <linux/minmax.h>
#include <linux/swab.h>
+/*
+ * 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
+ */
+#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; \
+})
+
#if !defined(find_next_bit) || !defined(find_next_zero_bit) || \
!defined(find_next_bit_le) || !defined(find_next_zero_bit_le) || \
!defined(find_next_and_bit)
@@ -77,14 +98,7 @@ EXPORT_SYMBOL(_find_next_bit);
*/
unsigned long _find_first_bit(const unsigned long *addr, 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(addr[idx], /* nop */, size);
}
EXPORT_SYMBOL(_find_first_bit);
#endif
@@ -97,15 +111,7 @@ unsigned long _find_first_and_bit(const unsigned long *addr1,
const unsigned long *addr2,
unsigned long size)
{
- unsigned long idx, val;
-
- for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
- val = addr1[idx] & addr2[idx];
- if (val)
- return min(idx * BITS_PER_LONG + __ffs(val), size);
- }
-
- return size;
+ return FIND_FIRST_BIT(addr1[idx] & addr2[idx], /* nop */, size);
}
EXPORT_SYMBOL(_find_first_and_bit);
#endif
@@ -116,14 +122,7 @@ EXPORT_SYMBOL(_find_first_and_bit);
*/
unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size)
{
- unsigned long idx;
-
- for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
- if (addr[idx] != ~0UL)
- return min(idx * BITS_PER_LONG + ffz(addr[idx]), size);
- }
-
- return size;
+ return FIND_FIRST_BIT(~addr[idx], /* nop */, size);
}
EXPORT_SYMBOL(_find_first_zero_bit);
#endif