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Subject[PATCH v3 2/4] lib/find_bit: create find_first_zero_bit_le()
Date
find_first_zero_bit_le() is an alias to find_next_zero_bit_le(),
despite that 'next' is known to be slower than 'first' version.

Now that we have common FIND_FIRST_BIT() macro helper, it's trivial
to implement find_first_zero_bit_le() as a real function.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
include/linux/find.h | 23 ++++++++++++++++++-----
lib/find_bit.c | 14 ++++++++++++++
2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/include/linux/find.h b/include/linux/find.h
index 424ef67d4a42..a1861d0ba533 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -17,6 +17,10 @@ extern unsigned long _find_first_and_bit(const unsigned long *addr1,
extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);
extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);

+#ifdef __BIG_ENDIAN
+unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size);
+#endif
+
#ifndef find_next_bit
/**
* find_next_bit - find the next set bit in a memory region
@@ -251,6 +255,20 @@ unsigned long find_next_zero_bit_le(const void *addr, unsigned
}
#endif

+#ifndef find_first_zero_bit_le
+static inline
+unsigned long find_first_zero_bit_le(const unsigned long *addr, unsigned long size)
+{
+ if (small_const_nbits(size)) {
+ unsigned long val = swab(*addr) | ~GENMASK(size - 1, 0);
+
+ return val == ~0UL ? size : ffz(val);
+ }
+
+ return _find_first_zero_bit_le(addr, size);
+}
+#endif
+
#ifndef find_next_bit_le
static inline
unsigned long find_next_bit_le(const void *addr, unsigned
@@ -270,11 +288,6 @@ unsigned long find_next_bit_le(const void *addr, unsigned
}
#endif

-#ifndef find_first_zero_bit_le
-#define find_first_zero_bit_le(addr, size) \
- find_next_zero_bit_le((addr), (size), 0)
-#endif
-
#else
#error "Please fix <asm/byteorder.h>"
#endif
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 894b656f6836..f4d9b9684811 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -160,3 +160,17 @@ unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,
return offset;
}
EXPORT_SYMBOL(find_next_clump8);
+
+#ifdef __BIG_ENDIAN
+#ifndef find_first_zero_bit_le
+/*
+ * Find the first cleared bit in an LE memory region.
+ */
+unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size)
+{
+ return FIND_FIRST_BIT(~addr[idx], swab, size);
+}
+EXPORT_SYMBOL(_find_first_zero_bit_le);
+#endif
+
+#endif /* __BIG_ENDIAN */
--
2.34.1
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