linux-kernel - [PATCH 7/7] mm: Unexport apply_to_page

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Date:   Mon, 12 Apr 2021 10:00:19 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     akpm@...ux-foundation.org
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        boris.ostrovsky@...cle.com, jgross@...e.com,
        sstabellini@...nel.org, x86@...nel.org,
        jani.nikula@...ux.intel.com, joonas.lahtinen@...ux.intel.com,
        rodrigo.vivi@...el.com, chris@...is-wilson.co.uk,
        intel-gfx@...ts.freedesktop.org, linux-mm@...ck.org,
        keescook@...omium.org, hch@....de
Subject: [PATCH 7/7] mm: Unexport apply_to_page_range()

Now that all module users of apply_to_page_range() have been removed,
unexport this function.

This is an unsafe function in that it gives direct access to the
page-tables.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 mm/memory.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2544,13 +2544,14 @@ static int __apply_to_page_range(struct
 /*
  * Scan a region of virtual memory, filling in page tables as necessary
  * and calling a provided function on each leaf page table.
+ *
+ * DO NOT EXPORT; this hands out our page-tables on a platter.
  */
 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
 			unsigned long size, pte_fn_t fn, void *data)
 {
 	return __apply_to_page_range(mm, addr, size, fn, data, true);
 }
-EXPORT_SYMBOL_GPL(apply_to_page_range);
 
 /*
  * Scan a region of virtual memory, calling a provided function on
@@ -2558,6 +2559,8 @@ EXPORT_SYMBOL_GPL(apply_to_page_range);
  *
  * Unlike apply_to_page_range, this does _not_ fill in page tables
  * where they are absent.
+ *
+ * DO NOT EXPORT; this hands out our page-tables on a platter.
  */
 int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr,
 				 unsigned long size, pte_fn_t fn, void *data)