On Sat, May 26, 2018 at 1:56 PM, Kent Overstreet
[off-list ref] wrote:

On Sat, May 26, 2018 at 11:16:42AM +0800, Liu Bo wrote:

quoted

quoted

+/*
+ * Returns pointer to the specified byte @offset within @radix, allocating it if
+ * necessary - newly allocated slots are always zeroed out:
+ */
+void *__genradix_ptr_alloc(struct __genradix *radix, size_t offset,
+                          gfp_t gfp_mask)
+{
+       struct genradix_node **n;

Any reason that " struct genradix_node ** " is used here instead of "
struct genradix_node * "?

Looks like this function only manipulates *n, am I missing something?

It stores to *n, when it has to allocate a node (including the root)

I see, thanks for the explanation.

thanks,
liubo