unify generic instances of csum_partial_copy_nocheck()

quite a few architectures have the same csum_partial_copy_nocheck() -
simply memcpy() the data and then return the csum of the copy.

hexagon, parisc, ia64, s390, um: explicitly spelled out that way.

arc, arm64, csky, h8300, m68k/nommu, microblaze, mips/GENERIC_CSUM, nds32,
nios2, openrisc, riscv, unicore32: end up picking the same thing spelled
out in lib/checksum.h (with varying amounts of perversions along the way).

everybody else (alpha, arm, c6x, m68k/mmu, mips/!GENERIC_CSUM, powerpc,
sh, sparc, x86, xtensa) have non-generic variants.  For all except c6x
the declaration is in their asm/checksum.h.  c6x uses the wrapper
from asm-generic/checksum.h that would normally lead to the lib/checksum.h
instance, but in case of c6x we end up using an asm function from arch/c6x
instead.

Screw that mess - have architectures with private instances define
_HAVE_ARCH_CSUM_AND_COPY in their asm/checksum.h and have the default
one right in net/checksum.h conditional on _HAVE_ARCH_CSUM_AND_COPY
*not* defined.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/alpha/include/asm/checksum.h

@@ -42,6 +42,7 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  * better 64-bit) boundary
  */
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
 
 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);

arch/arm/include/asm/checksum.h

@@ -41,6 +41,7 @@ __wsum
 csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 static inline
 __wsum csum_and_copy_from_user (const void __user *src, void *dst,
 				      int len, __wsum sum, int *err_ptr)

arch/c6x/include/asm/checksum.h

@@ -26,6 +26,9 @@ csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
 }
 #define csum_tcpudp_nofold csum_tcpudp_nofold
 
+#define _HAVE_ARCH_CSUM_AND_COPY
+extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+
 #include <asm-generic/checksum.h>
 
 #endif /* _ASM_C6X_CHECKSUM_H */

arch/hexagon/include/asm/checksum.h

@@ -9,17 +9,6 @@
 #define do_csum	do_csum
 unsigned int do_csum(const void *voidptr, int len);
 
-/*
- * the same as csum_partial, but copies from src while it
- * checksums
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-#define csum_partial_copy_nocheck csum_partial_copy_nocheck
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-					int len, __wsum sum);
-
 /*
  * computes the checksum of the TCP/UDP pseudo-header
  * returns a 16-bit checksum, already complemented

arch/hexagon/lib/checksum.c

@@ -176,14 +176,3 @@ unsigned int do_csum(const void *voidptr, int len)
 
 	return 0xFFFF & sum0;
 }
-
-/*
- * copy from ds while checksumming, otherwise like csum_partial
- */
-__wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-EXPORT_SYMBOL(csum_partial_copy_nocheck);

arch/ia64/include/asm/checksum.h

@@ -37,9 +37,6 @@ extern __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-extern __wsum csum_partial_copy_nocheck(const void *src, void *dst,
-					       int len, __wsum sum);
-
 /*
  * This routine is used for miscellaneous IP-like checksums, mainly in
  * icmp.c

arch/ia64/lib/csum_partial_copy.c

@@ -96,18 +96,3 @@ unsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum)
 out:
 	return result;
 }
-
-/*
- * XXX Fixme
- *
- * This is very ugly but temporary. THIS NEEDS SERIOUS ENHANCEMENTS.
- * But it's very tricky to get right even in C.
- */
-__wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-
-EXPORT_SYMBOL(csum_partial_copy_nocheck);

arch/m68k/include/asm/checksum.h

@@ -31,6 +31,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum);
  */
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 extern __wsum csum_and_copy_from_user(const void __user *src,
 						void *dst,
 						int len, __wsum sum,

arch/mips/include/asm/checksum.h

@@ -101,9 +101,9 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
  * the same as csum_partial, but copies from user space (but on MIPS
  * we have just one address space, so this is identical to the above)
  */
+#define _HAVE_ARCH_CSUM_AND_COPY
 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 				       int len, __wsum sum);
-#define csum_partial_copy_nocheck csum_partial_copy_nocheck
 
 /*
  *	Fold a partial checksum without adding pseudo headers

arch/nios2/include/asm/checksum.h

@@ -12,10 +12,6 @@
 
 /* Take these from lib/checksum.c */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
-__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len,
-				__wsum sum);
-#define csum_partial_copy_nocheck csum_partial_copy_nocheck
-
 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
 extern __sum16 ip_compute_csum(const void *buff, int len);
 

arch/parisc/include/asm/checksum.h

@@ -18,14 +18,6 @@
  */
 extern __wsum csum_partial(const void *, int, __wsum);
 
-/*
- * The same as csum_partial, but copies from src while it checksums.
- *
- * Here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-extern __wsum csum_partial_copy_nocheck(const void *, void *, int, __wsum);
-
 /*
  *	Optimized for IP headers, which always checksum on 4 octet boundaries.
  *

arch/parisc/lib/checksum.c

@@ -106,20 +106,3 @@ __wsum csum_partial(const void *buff, int len, __wsum sum)
 }
 
 EXPORT_SYMBOL(csum_partial);
-
-/*
- * copy while checksumming, otherwise like csum_partial
- */
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-				       int len, __wsum sum)
-{
-	/*
-	 * It's 2:30 am and I don't feel like doing it real ...
-	 * This is lots slower than the real thing (tm)
-	 */
-	sum = csum_partial(src, len, sum);
-	memcpy(dst, src, len);
-
-	return sum;
-}
-EXPORT_SYMBOL(csum_partial_copy_nocheck);

arch/powerpc/include/asm/checksum.h

@@ -29,6 +29,7 @@ extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 				    int len, __wsum sum, int *err_ptr);
 
+#define _HAVE_ARCH_CSUM_AND_COPY
 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
         csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
 

arch/s390/include/asm/checksum.h

@@ -39,13 +39,6 @@ csum_partial(const void *buff, int len, __wsum sum)
 	return sum;
 }
 
-static inline __wsum
-csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
-{
-        memcpy(dst,src,len);
-	return csum_partial(dst, len, sum);
-}
-
 /*
  *      Fold a partial checksum without adding pseudo headers
  */

arch/sh/include/asm/checksum_32.h

@@ -34,6 +34,7 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 					    int len, __wsum sum,
 					    int *src_err_ptr, int *dst_err_ptr);
 
+#define _HAVE_ARCH_CSUM_AND_COPY
 /*
  *	Note: when you get a NULL pointer exception here this means someone
  *	passed in an incorrect kernel address to one of these functions.

arch/sparc/include/asm/checksum.h

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef ___ASM_SPARC_CHECKSUM_H
 #define ___ASM_SPARC_CHECKSUM_H
+#define _HAVE_ARCH_CSUM_AND_COPY
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 #if defined(__sparc__) && defined(__arch64__)
 #include <asm/checksum_64.h>

arch/x86/include/asm/checksum.h

 /* SPDX-License-Identifier: GPL-2.0 */
 #define  _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
 #define HAVE_CSUM_COPY_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 #ifdef CONFIG_X86_32
 # include <asm/checksum_32.h>
 #else

arch/x86/um/asm/checksum.h

@@ -20,22 +20,6 @@
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-/*
- *	Note: when you get a NULL pointer exception here this means someone
- *	passed in an incorrect kernel address to one of these functions.
- *
- *	If you use these functions directly please don't forget the
- *	access_ok().
- */
-
-static __inline__
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-				       int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-
 /**
  * csum_fold - Fold and invert a 32bit checksum.
  * sum: 32bit unfolded sum

arch/xtensa/include/asm/checksum.h

@@ -41,6 +41,7 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 					    int len, __wsum sum,
 					    int *src_err_ptr, int *dst_err_ptr);
 
+#define _HAVE_ARCH_CSUM_AND_COPY
 /*
  *	Note: when you get a NULL pointer exception here this means someone
  *	passed in an incorrect kernel address to one of these functions.

include/asm-generic/checksum.h

@@ -16,18 +16,6 @@
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-/*
- * the same as csum_partial, but copies from src while it
- * checksums
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-#ifndef csum_partial_copy_nocheck
-__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len,
-		__wsum sum);
-#endif
-
 #ifndef ip_fast_csum
 /*
  * This is a version of ip_compute_csum() optimized for IP headers,

include/net/checksum.h

@@ -47,6 +47,15 @@ static __inline__ __wsum csum_and_copy_to_user
 }
 #endif
 
+#ifndef _HAVE_ARCH_CSUM_AND_COPY
+static inline __wsum
+csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
+{
+	memcpy(dst, src, len);
+	return csum_partial(dst, len, sum);
+}
+#endif
+
 #ifndef HAVE_ARCH_CSUM_ADD
 static inline __wsum csum_add(__wsum csum, __wsum addend)
 {

lib/checksum.c

@@ -145,17 +145,6 @@ __sum16 ip_compute_csum(const void *buff, int len)
 }
 EXPORT_SYMBOL(ip_compute_csum);
 
-/*
- * copy from ds while checksumming, otherwise like csum_partial
- */
-__wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-EXPORT_SYMBOL(csum_partial_copy_nocheck);
-
 #ifndef csum_tcpudp_nofold
 static inline u32 from64to32(u64 x)
 {