[uaccess] Rename userptr_sub() to userptr_diff()

Clarify the intended usage of userptr_sub() by renaming it to
userptr_diff() (to avoid confusion with userptr_add()), and fix the
existing call sites that erroneously use userptr_sub() to subtract an
offset from a userptr_t value.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

5 files changed, 22 insertions, 22 deletions

diff --git a/src/arch/x86/image/bzimage.c b/src/arch/x86/image/bzimage.c
index d2534bdad..b4a78cdfc 100644
--- a/src/arch/x86/image/bzimage.c
+++ b/src/arch/x86/image/bzimage.c
@@ -476,7 +476,7 @@ static void bzimage_load_initrds ( struct image *image,
 	/* Find highest initrd */
 	for_each_image ( initrd ) {
 		if ( ( highest == NULL ) ||
-		     ( userptr_sub ( initrd->data, highest->data ) > 0 ) ) {
+		     ( userptr_diff ( initrd->data, highest->data ) > 0 ) ) {
 			highest = initrd;
 		}
 	}
diff --git a/src/arch/x86/image/initrd.c b/src/arch/x86/image/initrd.c
index d7b1f5773..c0a56b7f6 100644
--- a/src/arch/x86/image/initrd.c
+++ b/src/arch/x86/image/initrd.c
@@ -61,10 +61,10 @@ static userptr_t initrd_squash_high ( userptr_t top ) {
 		/* Find the highest image not yet in its final position */
 		highest = NULL;
 		for_each_image ( initrd ) {
-			if ( ( userptr_sub ( initrd->data, current ) < 0 ) &&
+			if ( ( userptr_diff ( initrd->data, current ) < 0 ) &&
 			     ( ( highest == NULL ) ||
-			       ( userptr_sub ( initrd->data,
-					       highest->data ) > 0 ) ) ) {
+			       ( userptr_diff ( initrd->data,
+						highest->data ) > 0 ) ) ) {
 				highest = initrd;
 			}
 		}
@@ -74,7 +74,7 @@ static userptr_t initrd_squash_high ( userptr_t top ) {
 		/* Move this image to its final position */
 		len = ( ( highest->len + INITRD_ALIGN - 1 ) &
 			~( INITRD_ALIGN - 1 ) );
-		current = userptr_sub ( current, len );
+		current = userptr_add ( current, -len );
 		DBGC ( &images, "INITRD squashing %s [%#08lx,%#08lx)->"
 		       "[%#08lx,%#08lx)\n", highest->name,
 		       user_to_phys ( highest->data, 0 ),
@@ -87,10 +87,10 @@ static userptr_t initrd_squash_high ( userptr_t top ) {
 
 	/* Copy any remaining initrds (e.g. embedded images) to the region */
 	for_each_image ( initrd ) {
-		if ( userptr_sub ( initrd->data, top ) >= 0 ) {
+		if ( userptr_diff ( initrd->data, top ) >= 0 ) {
 			len = ( ( initrd->len + INITRD_ALIGN - 1 ) &
 				~( INITRD_ALIGN - 1 ) );
-			current = userptr_sub ( current, len );
+			current = userptr_add ( current, -len );
 			DBGC ( &images, "INITRD copying %s [%#08lx,%#08lx)->"
 			       "[%#08lx,%#08lx)\n", initrd->name,
 			       user_to_phys ( initrd->data, 0 ),
@@ -235,7 +235,7 @@ void initrd_reshuffle ( userptr_t bottom ) {
 
 	/* Calculate limits of available space for initrds */
 	top = initrd_top;
-	if ( userptr_sub ( initrd_bottom, bottom ) > 0 )
+	if ( userptr_diff ( initrd_bottom, bottom ) > 0 )
 		bottom = initrd_bottom;
 
 	/* Debug */
@@ -248,7 +248,7 @@ void initrd_reshuffle ( userptr_t bottom ) {
 
 	/* Calculate available free space */
 	free = bottom;
-	free_len = userptr_sub ( used, free );
+	free_len = userptr_diff ( used, free );
 
 	/* Bubble-sort initrds into desired order */
 	while ( initrd_swap_any ( free, free_len ) ) {}
@@ -270,9 +270,9 @@ int initrd_reshuffle_check ( size_t len, userptr_t bottom ) {
 
 	/* Calculate limits of available space for initrds */
 	top = initrd_top;
-	if ( userptr_sub ( initrd_bottom, bottom ) > 0 )
+	if ( userptr_diff ( initrd_bottom, bottom ) > 0 )
 		bottom = initrd_bottom;
-	available = userptr_sub ( top, bottom );
+	available = userptr_diff ( top, bottom );
 
 	/* Allow for a sensible minimum amount of free space */
 	len += INITRD_MIN_FREE_LEN;
diff --git a/src/arch/x86/include/librm.h b/src/arch/x86/include/librm.h
index 84b345d3a..c664bff2c 100644
--- a/src/arch/x86/include/librm.h
+++ b/src/arch/x86/include/librm.h
@@ -143,9 +143,9 @@ UACCESS_INLINE ( librm, userptr_add ) ( userptr_t userptr, off_t offset ) {
 }
 
 static inline __always_inline off_t
-UACCESS_INLINE ( librm, userptr_sub ) ( userptr_t userptr,
-					userptr_t subtrahend ) {
-	return trivial_userptr_sub ( userptr, subtrahend );
+UACCESS_INLINE ( librm, userptr_diff ) ( userptr_t userptr,
+					 userptr_t subtrahend ) {
+	return trivial_userptr_diff ( userptr, subtrahend );
 }
 
 static inline __always_inline void
diff --git a/src/include/ipxe/linux/linux_uaccess.h b/src/include/ipxe/linux/linux_uaccess.h
index a642b6163..b29aa14bd 100644
--- a/src/include/ipxe/linux/linux_uaccess.h
+++ b/src/include/ipxe/linux/linux_uaccess.h
@@ -75,9 +75,9 @@ UACCESS_INLINE ( linux, userptr_add ) ( userptr_t userptr, off_t offset ) {
 }
 
 static inline __always_inline off_t
-UACCESS_INLINE ( linux, userptr_sub ) ( userptr_t userptr,
-					userptr_t subtrahend ) {
-	return trivial_userptr_sub ( userptr, subtrahend );
+UACCESS_INLINE ( linux, userptr_diff ) ( userptr_t userptr,
+					 userptr_t subtrahend ) {
+	return trivial_userptr_diff ( userptr, subtrahend );
 }
 
 static inline __always_inline void
diff --git a/src/include/ipxe/uaccess.h b/src/include/ipxe/uaccess.h
index b71361cab..2575faca5 100644
--- a/src/include/ipxe/uaccess.h
+++ b/src/include/ipxe/uaccess.h
@@ -96,7 +96,7 @@ trivial_userptr_add ( userptr_t userptr, off_t offset ) {
  * @ret offset		Offset
  */
 static inline __always_inline off_t
-trivial_userptr_sub ( userptr_t userptr, userptr_t subtrahend ) {
+trivial_userptr_diff ( userptr_t userptr, userptr_t subtrahend ) {
 	return ( userptr - subtrahend );
 }
 
@@ -248,9 +248,9 @@ UACCESS_INLINE ( flat, userptr_add ) ( userptr_t userptr, off_t offset ) {
 }
 
 static inline __always_inline off_t
-UACCESS_INLINE ( flat, userptr_sub ) ( userptr_t userptr,
-				       userptr_t subtrahend ) {
-	return trivial_userptr_sub ( userptr, subtrahend );
+UACCESS_INLINE ( flat, userptr_diff ) ( userptr_t userptr,
+					userptr_t subtrahend ) {
+	return trivial_userptr_diff ( userptr, subtrahend );
 }
 
 static inline __always_inline void
@@ -349,7 +349,7 @@ userptr_t userptr_add ( userptr_t userptr, off_t offset );
  * @v subtrahend	User pointer to be subtracted
  * @ret offset		Offset
  */
-off_t userptr_sub ( userptr_t userptr, userptr_t subtrahend );
+off_t userptr_diff ( userptr_t userptr, userptr_t subtrahend );
 
 /**
  * Convert virtual address to a physical address