The patch titled arch/arm: eliminate NULL test and memset after alloc_bootmem has been added to the -mm tree. Its filename is arch-arm-eliminate-null-test-and-memset-after-alloc_bootmem.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this 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 drivers-char-agp-add-missing-pci_dev_get.patch drivers-mtd-maps-nettelc-use-array_size.patch net-tipc-bcasth-use-array_size.patch drivers-isdn-misdn-use-array_size.patch drivers-pci-hotplug-add-missing-pci_dev_get.patch drivers-message-fusion-use-array_size.patch fs-namespacec-drop-code-after-return.patch arch-arm-eliminate-null-test-and-memset-after-alloc_bootmem.patch arch-avr32-eliminate-null-test-and-memset-after-alloc_bootmem.patch arch-ia64-eliminate-null-test-and-memset-after-alloc_bootmem.patch arch-powerpc-eliminate-null-test-and-memset-after-alloc_bootmem.patch mm-page_allocc-eliminate-null-test-and-memset-after-alloc_bootmem.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html