[PATCH v2 1/2] powerpc32: put csum_tcpudp_magic inline

csum_tcpudp_magic() is only a few instructions, and does not modifies any other
register than the returned result. So it is not worth having it as a separate
function and suffer function branching and saving of volatile registers.
This patch makes it inline by use of the already existing csum_tcpudp_nofold()
function.

Signed-off-by: Christophe Leroy <redacted>

---
v2: no change

 arch/powerpc/include/asm/checksum.h | 15 +++++++++++++++
 arch/powerpc/lib/checksum_32.S      | 16 ----------------
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index 8251a3b..cfe806a 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h

@@ -19,6 +19,7 @@
 #else
 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
 
+#ifdef __powerpc64__
 /*
  * computes the checksum of the TCP/UDP pseudo-header
  * returns a 16-bit checksum, already complemented

@@ -27,6 +28,7 @@ extern __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 					unsigned short len,
 					unsigned short proto,
 					__wsum sum);
+#endif
 
 /*
  * computes the checksum of a memory block at buff, length len,

@@ -127,6 +129,19 @@ static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 #endif
 }
 
+#ifndef __powerpc64__
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
+					unsigned short len,
+					unsigned short proto,
+					__wsum sum)
+{
+	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
+}
+#endif
 #endif
 #endif /* __KERNEL__ */
 #endif

diff --git a/arch/powerpc/lib/checksum_32.S b/arch/powerpc/lib/checksum_32.S
index 7874e8a..6d67e05 100644
--- a/arch/powerpc/lib/checksum_32.S
+++ b/arch/powerpc/lib/checksum_32.S

@@ -41,22 +41,6 @@ _GLOBAL(ip_fast_csum)
 	blr
 
 /*
- * Compute checksum of TCP or UDP pseudo-header:
- *   csum_tcpudp_magic(saddr, daddr, len, proto, sum)
- */	
-_GLOBAL(csum_tcpudp_magic)
-	rlwimi	r5,r6,16,0,15	/* put proto in upper half of len */
-	addc	r0,r3,r4	/* add 4 32-bit words together */
-	adde	r0,r0,r5
-	adde	r0,r0,r7
-	addze	r0,r0		/* add in final carry */
-	rlwinm	r3,r0,16,0,31	/* fold two halves together */
-	add	r3,r0,r3
-	not	r3,r3
-	srwi	r3,r3,16
-	blr
-
-/*
  * computes the checksum of a memory block at buff, length len,
  * and adds in "sum" (32-bit)
  *

-- 
2.1.0

On Tue, 2015-02-03 at 12:39 +0100, Christophe Leroy wrote:

csum_tcpudp_magic() is only a few instructions, and does not modifies any other
register than the returned result. So it is not worth having it as a separate
function and suffer function branching and saving of volatile registers.
This patch makes it inline by use of the already existing csum_tcpudp_nofold()
function.

Signed-off-by: Christophe Leroy <redacted>

---
v2: no change

 arch/powerpc/include/asm/checksum.h | 15 +++++++++++++++
 arch/powerpc/lib/checksum_32.S      | 16 ----------------
 2 files changed, 15 insertions(+), 16 deletions(-)

The 64-bit version is pretty similar to the 32-bit -- why only use
csum_tcpudp_nofold() on 32-bit?

-Scott

Le 25/03/2015 03:10, Scott Wood a écrit :

On Tue, 2015-02-03 at 12:39 +0100, Christophe Leroy wrote:

quoted

csum_tcpudp_magic() is only a few instructions, and does not modifies any other
register than the returned result. So it is not worth having it as a separate
function and suffer function branching and saving of volatile registers.
This patch makes it inline by use of the already existing csum_tcpudp_nofold()
function.

Signed-off-by: Christophe Leroy <redacted>

---
v2: no change

  arch/powerpc/include/asm/checksum.h | 15 +++++++++++++++
  arch/powerpc/lib/checksum_32.S      | 16 ----------------
  2 files changed, 15 insertions(+), 16 deletions(-)

The 64-bit version is pretty similar to the 32-bit -- why only use
csum_tcpudp_nofold() on 32-bit?

I did it only on 32-bit because I have no way to test it on 64-bits, but 
I can do it for 64 bits as well, no problem.

Christophe

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