maple: change the pointer name from maple_enode to maple_enode_p

The current name of the pointer to struct maple_enode is also maple_enode. This is correct from the grammar point but can be comfusing. Besides it seems in Linux it prefers typedef struct foo *foo_p;, e.g. typedef struct cpumask *cpumask_var_t; and typedef struct cgraph_node *cgraph_node_ptr;. I use re to search in the Linux project and cannot find another example in typedef struct foo *foo; style.

This also results in a bug in the bindings of the rust-for-linux subsystem, which can be seen in this github issue.

https://github.com/Rust-for-Linux/linux/issues/795

The struct pointer maple_enode and maple_pnode are not used. It is safe to change it to a new name.

---
 include/linux/maple_tree.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 2c9dede989c7..4886e019a2b5 100644
@@ -72,8 +72,8 @@
  *   0x010 : 32 bit values, type in 0-2, slot in 3-6
  *   0x110 : 64 bit values, type in 0-2, slot in 3-6
  */
-typedef struct maple_enode *maple_enode; /* encoded node */
-typedef struct maple_pnode *maple_pnode; /* parent node */
+typedef struct maple_enode *maple_enode_p; /* encoded node */
+typedef struct maple_pnode *maple_pnode_p; /* parent node */
 
 /*
  * This metadata is used to optimize the gap updating code and in reverse

2.17.1

There is no definition of the struct maple_enode or maple_pnode. This struct is only used as a pointer. There are some comments about this pointer, which will be gone if we delete these two typedef statements.

If you worry about generating a not used data type, it may be better to change struct maple_enode *foo to maple_enode_p foo. This keeps the code more readable and used the maple_enode_p type.