From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753840Ab1GZPg7 (ORCPT ); Tue, 26 Jul 2011 11:36:59 -0400 Received: from mail-ey0-f171.google.com ([209.85.215.171]:54562 "EHLO mail-ey0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753611Ab1GZPf6 (ORCPT ); Tue, 26 Jul 2011 11:35:58 -0400 From: Tejun Heo To: benh@kernel.crashing.org, yinghai@kernel.org, hpa@zytor.com, tony.luck@intel.com, ralf@linux-mips.org, schwidefsky@de.ibm.com, liqin.chen@sunplusct.com, lethal@linux-sh.org, davem@davemloft.net, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Cc: mingo@redhat.com, Tejun Heo Subject: [PATCH 09/23] memblock: Make memblock functions handle overflowing range @size Date: Tue, 26 Jul 2011 17:35:20 +0200 Message-Id: <1311694534-5161-10-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.6 In-Reply-To: <1311694534-5161-1-git-send-email-tj@kernel.org> References: <1311694534-5161-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow memblock users to specify range where @base + @size overflows and automatically cap it at maximum. This makes the interface more robust and specifying till-the-end-of-memory easier. Signed-off-by: Tejun Heo Cc: Benjamin Herrenschmidt Cc: Yinghai Lu --- mm/memblock.c | 15 ++++++++++++--- 1 files changed, 12 insertions(+), 3 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index 8b38cd9..53d214a 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -49,6 +49,12 @@ static inline const char *memblock_type_name(struct memblock_type *type) return "unknown"; } +/* adjust *@size so that (@base + *@size) doesn't overflow, return new size */ +static inline phys_addr_t memblock_cap_size(phys_addr_t base, phys_addr_t *size) +{ + return *size = min(*size, (phys_addr_t)ULLONG_MAX - base); +} + /* * Address comparison utilities */ @@ -328,7 +334,8 @@ static int __init_memblock memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size) { bool insert = false; - phys_addr_t obase = base, end = base + size; + phys_addr_t obase = base; + phys_addr_t end = base + memblock_cap_size(base, &size); int i, nr_new; /* special case for empty array */ @@ -420,7 +427,7 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, phys_addr_t base, phys_addr_t size, int *start_rgn, int *end_rgn) { - phys_addr_t end = base + size; + phys_addr_t end = base + memblock_cap_size(base, &size); int i; *start_rgn = *end_rgn = 0; @@ -862,16 +869,18 @@ int __init_memblock memblock_is_memory(phys_addr_t addr) int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size) { int idx = memblock_search(&memblock.memory, base); + phys_addr_t end = base + memblock_cap_size(base, &size); if (idx == -1) return 0; return memblock.memory.regions[idx].base <= base && (memblock.memory.regions[idx].base + - memblock.memory.regions[idx].size) >= (base + size); + memblock.memory.regions[idx].size) >= end; } int __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size) { + memblock_cap_size(base, &size); return memblock_overlaps_region(&memblock.reserved, base, size) >= 0; } -- 1.7.6