ext2 has nothing to do with this logic.  Clean up the code with
xen/byteswap.h which now has an unsigned long helper.

No functional change.

Signed-off-by: Lin Liu <lin.liu@citrix.com>
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien@xen.org>
Cc: Bertrand Marquis <bertrand.marquis@arm.com>
Cc: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
This patche is not well tested without running environment for arm
---
 xen/arch/arm/arm64/lib/find_next_bit.c | 36 +++++---------------------
 1 file changed, 6 insertions(+), 30 deletions(-)

diff --git a/xen/arch/arm/arm64/lib/find_next_bit.c b/xen/arch/arm/arm64/lib/find_next_bit.c
index 8ebf8bfe97..e3b3720ff4 100644
--- a/xen/arch/arm/arm64/lib/find_next_bit.c
+++ b/xen/arch/arm/arm64/lib/find_next_bit.c
@@ -161,30 +161,6 @@ EXPORT_SYMBOL(find_first_zero_bit);
 
 #ifdef __BIG_ENDIAN
 
-/* include/linux/byteorder does not support "unsigned long" type */
-static inline unsigned long ext2_swabp(const unsigned long * x)
-{
-#if BITS_PER_LONG == 64
-	return (unsigned long) __swab64p((u64 *) x);
-#elif BITS_PER_LONG == 32
-	return (unsigned long) __swab32p((u32 *) x);
-#else
-#error BITS_PER_LONG not defined
-#endif
-}
-
-/* include/linux/byteorder doesn't support "unsigned long" type */
-static inline unsigned long ext2_swab(const unsigned long y)
-{
-#if BITS_PER_LONG == 64
-	return (unsigned long) __swab64((u64) y);
-#elif BITS_PER_LONG == 32
-	return (unsigned long) __swab32((u32) y);
-#else
-#error BITS_PER_LONG not defined
-#endif
-}
-
 #ifndef find_next_zero_bit_le
 unsigned long find_next_zero_bit_le(const void *addr, unsigned
 		long size, unsigned long offset)
@@ -199,7 +175,7 @@ unsigned long find_next_zero_bit_le(const void *addr, unsigned
 	size -= result;
 	offset &= (BITS_PER_LONG - 1UL);
 	if (offset) {
-		tmp = ext2_swabp(p++);
+		tmp = bswap_ul(*p++);
 		tmp |= (~0UL >> (BITS_PER_LONG - offset));
 		if (size < BITS_PER_LONG)
 			goto found_first;
@@ -217,7 +193,7 @@ unsigned long find_next_zero_bit_le(const void *addr, unsigned
 	}
 	if (!size)
 		return result;
-	tmp = ext2_swabp(p);
+	tmp = bswap_ul(*p);
 found_first:
 	tmp |= ~0UL << size;
 	if (tmp == ~0UL)	/* Are any bits zero? */
@@ -226,7 +202,7 @@ found_middle:
 	return result + ffz(tmp);
 
 found_middle_swap:
-	return result + ffz(ext2_swab(tmp));
+	return result + ffz(bswap_ul(tmp));
 }
 EXPORT_SYMBOL(find_next_zero_bit_le);
 #endif
@@ -245,7 +221,7 @@ unsigned long find_next_bit_le(const void *addr, unsigned
 	size -= result;
 	offset &= (BITS_PER_LONG - 1UL);
 	if (offset) {
-		tmp = ext2_swabp(p++);
+		tmp = bswap_ul(*p++);
 		tmp &= (~0UL << offset);
 		if (size < BITS_PER_LONG)
 			goto found_first;
@@ -264,7 +240,7 @@ unsigned long find_next_bit_le(const void *addr, unsigned
 	}
 	if (!size)
 		return result;
-	tmp = ext2_swabp(p);
+	tmp = bswap_ul(*p);
 found_first:
 	tmp &= (~0UL >> (BITS_PER_LONG - size));
 	if (tmp == 0UL)		/* Are any bits set? */
@@ -273,7 +249,7 @@ found_middle:
 	return result + __ffs(tmp);
 
 found_middle_swap:
-	return result + __ffs(ext2_swab(tmp));
+	return result + __ffs(bswap_ul(tmp));
 }
 EXPORT_SYMBOL(find_next_bit_le);
 #endif
-- 
2.27.0

Hi,

On 10/05/2022 11:15, Lin Liu wrote:
> ext2 has nothing to do with this logic.

This code was a verbatim copy from Linux. Looking at the history, I am 
not sure there was even a connection with the ext2 filesystem (I guess 
this is what you mean?).

So I would drop this and simply say that we could use the new helpers.

>  Clean up the code with
> xen/byteswap.h which now has an unsigned long helper.
> 
> No functional change.
> 
> Signed-off-by: Lin Liu <lin.liu@citrix.com>

Other that what I wrote above:

Acked-by: Julien Grall <jgrall@amazon.com>

Cheers,

-- 
Julien Grall

On 10/05/2022 11:15, Lin Liu wrote:
> ext2 has nothing to do with this logic.  Clean up the code with
> xen/byteswap.h which now has an unsigned long helper.
>
> No functional change.
>
> Signed-off-by: Lin Liu <lin.liu@citrix.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>