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From: David Howells <dhowells@redhat.com>
To: torvalds@osdl.org
Cc: linux-kernel@vger.kernel.org, Julia Lawall <julia@diku.dk>,
	David Howells <dhowells@redhat.com>
Subject: [PATCH 4/7] FRV: Eliminate NULL test and memset after alloc_bootmem
Date: Wed, 15 Oct 2008 16:51:04 +0100	[thread overview]
Message-ID: <20081015155104.2158.33413.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <20081015155048.2158.35981.stgit@warthog.procyon.org.uk>

From: Julia Lawall <julia@diku.dk>

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.

 arch/frv/mm/init.c |    2 --
 1 file changed, 2 deletions(-)

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: David Howells <dhowells@redhat.com>
---

 arch/frv/mm/init.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)


diff --git a/arch/frv/mm/init.c b/arch/frv/mm/init.c
index 1b851db..0708284 100644
--- a/arch/frv/mm/init.c
+++ b/arch/frv/mm/init.c
@@ -87,8 +87,6 @@ void __init paging_init(void)
 
 		pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
 
-		memset(pkmap_page_table, 0, PAGE_SIZE);
-
 		pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
 		pue = pud_offset(pge, PKMAP_BASE);
 		pme = pmd_offset(pue, PKMAP_BASE);


  parent reply	other threads:[~2008-10-15 15:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-15 15:50 [PATCH 1/7] frv: use generic pci_enable_resources() David Howells
2008-10-15 15:50 ` [PATCH 2/7] FRV: Provide dma_map_page() for NOMMU and fix comments David Howells
2008-10-15 15:50 ` [PATCH 3/7] FRV: Switch unaligned access to the packed-struct implementation David Howells
2008-10-15 15:51 ` David Howells [this message]
2008-10-15 15:51 ` [PATCH 5/7] binfmt_elf_fdpic: Support auxvec base platform string David Howells
2008-10-15 15:51 ` [PATCH 6/7] binfmt_elf_fdpic: Convert initial stack alignment to arch_align_stack() David Howells
2008-10-15 15:51 ` [PATCH 7/7] binfmt_elf_fdpic: Wire up AT_EXECFD, AT_EXECFN, AT_SECURE David Howells

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