From: Julia Lawall <julia@diku.dk>
Date: Thu, 17 Jul 2008 19:16:33 +0000 (+0200)
Subject: arch/m68k/mm/motorola.c: Eliminate NULL test and memset after alloc_bootmem
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7b6b948fc0d60a704c15b1cd72345a98e759dd62;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

arch/m68k/mm/motorola.c: Eliminate NULL test and memset after alloc_bootmem

As noted by Akinobu Mita in patch b1fceac2b9e04d278316b2faddf276015fc06e3b,
alloc_bootmem and related functions never return NULL and always return a
zeroed region of memory.  Thus a NULL test or memset after calls to these
functions is unnecessary.

This was fixed using the following semantic patch.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression E;
statement S;
@@

E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
.. when != E
(
- BUG_ON (E == NULL);
|
- if (E == NULL) S
)

@@
expression E,E1;
@@

E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
.. when != E
- memset(E,0,E1);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index 30d34f285024..226795bdf355 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c
@@ -285,7 +285,6 @@ void __init paging_init(void)
 	 * to a couple of allocated pages
 	 */
 	empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
-	memset(empty_zero_page, 0, PAGE_SIZE);
 
 	/*
 	 * Set up SFC/DFC registers