xfs: Use variable-size array for nameval in xfs_attr_sf_entry

nameval is a variable-size array, so, define it as it, and remove all
the -1 magic number subtractions

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -992,9 +992,8 @@ xfs_attr_shortform_allfit(
 			return 0;
 		if (be16_to_cpu(name_loc->valuelen) >= XFS_ATTR_SF_ENTSIZE_MAX)
 			return 0;
-		bytes += sizeof(struct xfs_attr_sf_entry) - 1
-				+ name_loc->namelen
-				+ be16_to_cpu(name_loc->valuelen);
+		bytes += XFS_ATTR_SF_ENTSIZE_BYNAME(name_loc->namelen,
+					be16_to_cpu(name_loc->valuelen));
 	}
 	if ((dp->i_mount->m_flags & XFS_MOUNT_ATTR2) &&
 	    (dp->i_df.if_format != XFS_DINODE_FMT_BTREE) &&
@@ -1039,7 +1038,7 @@ xfs_attr_shortform_verify(
 		 * xfs_attr_sf_entry is defined with a 1-byte variable
 		 * array at the end, so we must subtract that off.
 		 */
-		if (((char *)sfep + sizeof(*sfep) - 1) >= endp)
+		if (((char *)sfep + sizeof(*sfep)) >= endp)
 			return __this_address;
 
 		/* Don't allow names with known bad length. */

fs/xfs/libxfs/xfs_attr_sf.h

@@ -27,11 +27,11 @@ typedef struct xfs_attr_sf_sort {
 } xfs_attr_sf_sort_t;
 
 #define XFS_ATTR_SF_ENTSIZE_BYNAME(nlen,vlen)	/* space name/value uses */ \
-	(((int)sizeof(struct xfs_attr_sf_entry)-1 + (nlen)+(vlen)))
+	((sizeof(struct xfs_attr_sf_entry) + (nlen) + (vlen)))
 #define XFS_ATTR_SF_ENTSIZE_MAX			/* max space for name&value */ \
 	((1 << (NBBY*(int)sizeof(uint8_t))) - 1)
 #define XFS_ATTR_SF_ENTSIZE(sfep)		/* space an entry uses */ \
-	((int)sizeof(struct xfs_attr_sf_entry)-1 + \
+	((int)sizeof(struct xfs_attr_sf_entry) + \
 		(sfep)->namelen+(sfep)->valuelen)
 #define XFS_ATTR_SF_NEXTENTRY(sfep)		/* next entry in struct */ \
 	((struct xfs_attr_sf_entry *)((char *)(sfep) + \

fs/xfs/libxfs/xfs_da_format.h

@@ -589,7 +589,7 @@ struct xfs_attr_shortform {
 		uint8_t namelen;	/* actual length of name (no NULL) */
 		uint8_t valuelen;	/* actual length of value (no NULL) */
 		uint8_t flags;	/* flags bits (see xfs_attr_leaf.h) */
-		uint8_t nameval[1];	/* name & value bytes concatenated */
+		uint8_t nameval[];	/* name & value bytes concatenated */
 	} list[1];			/* variable sized array */
 };