[PATCH] uml: s390 preparation, checksumming done in arch code

Checksum handling largely depends on the subarch.

Thus, I renamed i386 arch_csum_partial in arch/um/sys-i386/checksum.S back to
csum_partial, removed csum_partial from arch/um/kernel/checksum.c and shifted
EXPORT_SYMBOL(csum_partial) to arch/um/sys-i386/ksyms.c.

Then, csum_partial_copy_to and csum_partial_copy_from were shifted from
arch/um/kernel/checksum.c to arch/um/include/sysdep-i386/checksum.h and
inserted in the calling functions csum_partial_copy_from_user() and
csum_and_copy_to_user().

Now, arch/um/kernel/checksum.c is empty and removed.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/include/sysdep-i386/checksum.h

@@ -23,19 +23,6 @@
 unsigned int csum_partial(const unsigned char * buff, int len, 
 			  unsigned int sum);
 
-/*
- * the same as csum_partial, but copies from src while it
- * checksums, and handles user-space pointer exceptions correctly, when needed.
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-
-unsigned int csum_partial_copy_to(const unsigned char *src, unsigned char *dst,
-				  int len, int sum, int *err_ptr);
-unsigned int csum_partial_copy_from(const unsigned char *src, unsigned char *dst,
-				    int len, int sum, int *err_ptr);
-
 /*
  *	Note: when you get a NULL pointer exception here this means someone
  *	passed in an incorrect kernel address to one of these functions.
@@ -52,11 +39,24 @@ unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *
 	return(csum_partial(dst, len, sum));
 }
 
+/*
+ * the same as csum_partial, but copies from src while it
+ * checksums, and handles user-space pointer exceptions correctly, when needed.
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+
 static __inline__
 unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst,
 					 int len, int sum, int *err_ptr)
 {
-	return csum_partial_copy_from(src, dst, len, sum, err_ptr);
+	if(copy_from_user(dst, src, len)){
+		*err_ptr = -EFAULT;
+		return(-1);
+	}
+
+	return csum_partial(dst, len, sum);
 }
 
 /*
@@ -67,7 +67,6 @@ unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char
  */
 
 #define csum_partial_copy_fromuser csum_partial_copy_from_user
-unsigned int csum_partial_copy(const unsigned char *src, unsigned char *dst, int len, int sum);
 
 /*
  *	This is a version of ip_compute_csum() optimized for IP headers,
@@ -196,8 +195,14 @@ static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src,
 						     unsigned char *dst,
 						     int len, int sum, int *err_ptr)
 {
-	if (access_ok(VERIFY_WRITE, dst, len))
-		return(csum_partial_copy_to(src, dst, len, sum, err_ptr));
+	if (access_ok(VERIFY_WRITE, dst, len)){
+		if(copy_to_user(dst, src, len)){
+			*err_ptr = -EFAULT;
+			return(-1);
+		}
+
+		return csum_partial(src, len, sum);
+	}
 
 	if (len)
 		*err_ptr = -EFAULT;