lib/find_bit: create find_first_zero_bit_le()

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.

Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

diff --git a/include/linux/find.h b/include/linux/find.h
index 424ef67d4a426837eb49524634badbca72b07b3b..2464bff5de04ce3402949daccc5bfe5d1e51d806 100644 (file)
--- 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 void *addr, unsigned long size)
+{
+       if (small_const_nbits(size)) {
+               unsigned long val = swab(*(const unsigned long *)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 894b656f6836e356ff3a26dca36020399b54b253..61ec2992938bfe38756d87016fd05e34e3302bbb 100644 (file)
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -160,3 +160,19 @@ 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 */