The patch titled
arch/arm: eliminate NULL test and memset after alloc_bootmem
has been removed from the -mm tree. Its filename was
arch-arm-eliminate-null-test-and-memset-after-alloc_bootmem.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: arch/arm: eliminate NULL test and memset after alloc_bootmem
From: Julia Lawall <julia@xxxxxxx>
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 = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\|alloc_bootmem_node\|alloc_bootmem_low_pages_node\|alloc_bootmem_pages_node\)(...)
... when != E
(
- BUG_ON (E == NULL);
|
- if (E == NULL) S
)
@@
expression E,E1;
@@
E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\|alloc_bootmem_node\|alloc_bootmem_low_pages_node\|alloc_bootmem_pages_node\)(...)
... when != E
- memset(E,0,E1);
// </smpl>
Signed-off-by: Julia Lawall <julia@xxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm/mm/mmu.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff -puN arch/arm/mm/mmu.c~arch-arm-eliminate-null-test-and-memset-after-alloc_bootmem arch/arm/mm/mmu.c
--- a/arch/arm/mm/mmu.c~arch-arm-eliminate-null-test-and-memset-after-alloc_bootmem
+++ a/arch/arm/mm/mmu.c
@@ -826,7 +826,6 @@ static void __init devicemaps_init(struc
* Allocate the vector page early.
*/
vectors = alloc_bootmem_low_pages(PAGE_SIZE);
- BUG_ON(!vectors);
for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr));
@@ -911,10 +910,10 @@ void __init paging_init(struct machine_d
top_pmd = pmd_off_k(0xffff0000);
/*
- * allocate the zero page. Note that we count on this going ok.
+ * allocate the zero page. Note that this always succeeds and
+ * returns a zeroed result.
*/
zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
- memset(zero_page, 0, PAGE_SIZE);
empty_zero_page = virt_to_page(zero_page);
flush_dcache_page(empty_zero_page);
}
_
Patches currently in -mm which might be from julia@xxxxxxx are
linux-next.patch
arch-avr32-eliminate-null-test-and-memset-after-alloc_bootmem.patch
powerpc-chrp-add-missing-of_node_put-in-pcic.patch
powerpc-powermac-add-missing-of_node_put.patch
drivers-media-video-cx88-cx88-alsac-adjust-error-handling-code.patch
net-tipc-bcasth-use-array_size.patch
fs-namespacec-drop-code-after-return.patch
mm-page_allocc-eliminate-null-test-and-memset-after-alloc_bootmem.patch
drivers-macintosh-add-missing-of_node_put-in-therm_adt746xc.patch
drivers-rtc-correct-an-error-test.patch
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