fix(mapper): inline internal map_to_* functions

[mkroening]

When documenting #574 with --document-private-items, I got

warning: this URL is not a hyperlink
  --> src/structures/paging/mapper/mapped_page_table.rs:54:9
   |
54 |     /// https://github.com/rust-lang/rfcs/pull/2585.
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: bare URLs are not automatically turned into clickable links
   = note: `#[warn(rustdoc::bare_urls)]` on by default
help: use an automatic link instead
   |
54 |     /// <https://github.com/rust-lang/rfcs/pull/2585.>
   |         +                                            +

This made me take a closer look at the doc comment and the function added in c336201:

x86_64/src/structures/paging/mapper/mapped_page_table.rs

Lines 53 to 64 in f054b0c

	/// Helper function for implementing Mapper. Safe to limit the scope of unsafe, see
	/// https://github.com/rust-lang/rfcs/pull/2585.
	fn map_to_1gib<A>(
	&mut self,
	page: Page<Size1GiB>,
	frame: PhysFrame<Size1GiB>,
	flags: PageTableFlags,
	parent_table_flags: PageTableFlags,
	allocator: &mut A,
	) -> Result<MapperFlush<Size1GiB>, MapToError<Size1GiB>>
	where
	A: FrameAllocator<Size4KiB> + ?Sized,

I think it is better to avoid this intentional internal unsoundness. After making the function unsafe and removing the link from the doc comment, I noticed that these methods are only used in one place, which is already correctly unsafe. So instead, I inlined them.

If you prefer any of the other two options (fixing the hyperlink or making the function unsafe), please let me know. :)

[Freax13]

Thank you for your contribution!

I agree with your reasoning.

If you prefer, I can also target master, but this does not seem important enough for me.

By default, changes should target master, unless they are breaking changes.

[mkroening]

By default, changes should target master, unless they are breaking changes.

Done. 👍

[Freax13]

Thanks!