new free_contig() and changes to make drivers use it; so now we

have malloc/free, alloc_contig/free_contig and mmap/munmap nicely
paired up.

memory uses malloc/free instead of mmap/munmap as it doesn't have
to be contiguous for the ramdisks (and it might help if it doesn't!).

drivers/filter/util.c

@@ -20,9 +20,7 @@ char *flt_malloc(size_t size, char *sbuf, size_t ssize)
 	if (size <= ssize)
 		return sbuf;
 
-	p = mmap(NULL, size, PROT_READ | PROT_WRITE,
-		MAP_PREALLOC | MAP_CONTIG | MAP_ANON, -1, 0);
-	if (p == MAP_FAILED)
+	if(!(p = alloc_contig(size, 0, NULL)))
 		panic(__FILE__, "out of memory", size);
 
 	return p;
@@ -37,7 +35,7 @@ void flt_free(char *buf, size_t size, char *sbuf)
 	 */
 
 	if(buf != sbuf)
-		munmap(buf, size);
+		free_contig(buf, size);
 }
 
 /*===========================================================================*