mm/page_alloc: add kernel-docs for free_pages()

mm/page_alloc: add kernel-docs for free_pages()

Patch series "Cleanup free_pages() misuse", v3.

free_pages() is supposed to be called when we only have a virtual address.
__free_pages() is supposed to be called when we have a page.

There are a number of callers that use page_address() to get a page's
virtual address then call free_pages() on it when they should just call
__free_pages() directly.

Add kernel-docs for free_pages() to help callers better understand which
function they should be calling, and replace the obvious cases of misuse.

This patch (of 7):

Add kernel-docs to free_pages().  This will help callers understand when
to use it instead of __free_pages().

Link: https://lkml.kernel.org/r/20250903185921.1785167-1-vishal.moola@gmail.com
Link: https://lkml.kernel.org/r/20250903185921.1785167-2-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Justin Sanders <justin@coraid.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>