[PATCH bpf-next v3 1/4] net: checksum: move from32to16() to generic header

Puranjay Mohan
2024-10-26T12:54:09Z

from32to16() is used by lib/checksum.c and also by
arch/parisc/lib/checksum.c. The next patch will use it in the
bpf_csum_diff helper.

Move from32to16() to the include/net/checksum.h as csum_from32to16() and
remove other implementations.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
arch/parisc/lib/checksum.c | 13 ++-----------
include/net/checksum.h | 6 ++++++
lib/checksum.c | 11 +----------
3 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/arch/parisc/lib/checksum.c b/arch/parisc/lib/checksum.c
index 4818f3db84a5c..59d8c15d81bd0 100644
--- a/arch/parisc/lib/checksum.c
+++ b/arch/parisc/lib/checksum.c
@@ -25,15 +25,6 @@
: "=r"(_t) \
: "r"(_r), "0"(_t));

-static inline unsigned short from32to16(unsigned int x)
-{
- /* 32 bits --> 16 bits + carry */
- x = (x & 0xffff) + (x >> 16);
- /* 16 bits + carry --> 16 bits including carry */
- x = (x & 0xffff) + (x >> 16);
- return (unsigned short)x;
-}
-
static inline unsigned int do_csum(const unsigned char * buff, int len)
{
int odd, count;
@@ -85,7 +76,7 @@ static inline unsigned int do_csum(const unsigned char * buff, int len)
}
if (len & 1)
result += le16_to_cpu(*buff);
- result = from32to16(result);
+ result = csum_from32to16(result);
if (odd)
result = swab16(result);
out:
@@ -102,7 +93,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum)
{
unsigned int result = do_csum(buff, len);
addc(result, sum);
- return (__force __wsum)from32to16(result);
+ return (__force __wsum)csum_from32to16(result);
}

EXPORT_SYMBOL(csum_partial);
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 1338cb92c8e72..243f972267b8d 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -151,6 +151,12 @@ static inline void csum_replace(__wsum *csum, __wsum old, __wsum new)
*csum = csum_add(csum_sub(*csum, old), new);
}

+static inline unsigned short csum_from32to16(unsigned int sum)
+{
+ sum += (sum >> 16) | (sum << 16);
+ return (unsigned short)(sum >> 16);
+}
+
struct sk_buff;
void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
__be32 from, __be32 to, bool pseudohdr);
diff --git a/lib/checksum.c b/lib/checksum.c
index 6860d6b05a171..025ba546e1ec6 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -34,15 +34,6 @@
#include <asm/byteorder.h>

#ifndef do_csum
-static inline unsigned short from32to16(unsigned int x)
-{
- /* add up 16-bit and 16-bit for 16+c bit */
- x = (x & 0xffff) + (x >> 16);
- /* add up carry.. */
- x = (x & 0xffff) + (x >> 16);
- return x;
-}
-
static unsigned int do_csum(const unsigned char *buff, int len)
{
int odd;
@@ -90,7 +81,7 @@ static unsigned int do_csum(const unsigned char *buff, int len)
#else
result += (*buff << 8);
#endif
- result = from32to16(result);
+ result = csum_from32to16(result);
if (odd)
result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
out:
--
2.40.1