move iovec_iter_kernel out of header

core/lib/iovec.c

@@ -44,6 +44,22 @@ static errno_t iovec_iter_copy(iovec_iter_t* iter, void* buf, size_t len, bool t
     return status;
 }
 
+iovec_iter_t iovec_iter_kernel(iovec_t* iovecs, size_t count) {
+    size_t total = 0;
+    for (size_t i = 0; i < count; i++)
+        total += iovecs[i].len;
+
+    return (iovec_iter_t){
+        .iovecs = iovecs,
+        .iovecs_len = count,
+        .total_len = total,
+        .total_offset = 0,
+        .current_idx = 0,
+        .current_offset = 0,
+        .user = false,
+    };
+}
+
 errno_t iovec_iter_copy_to(iovec_iter_t* iter, const void* src, size_t len, size_t* out_copied) {
     return iovec_iter_copy(iter, (void*)src, len, true, out_copied);
 }