From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx173.postini.com [74.125.245.173]) by kanga.kvack.org (Postfix) with SMTP id D86516B004D for ; Fri, 16 Dec 2011 03:04:25 -0500 (EST) From: Petr Tesarik Subject: [PATCH] Do not round per_cpu_ptr_to_phys to page boundary Date: Fri, 16 Dec 2011 09:04:23 +0100 References: <201112140033.58951.ptesarik@suse.cz> <201112151139.32224.ptesarik@suse.cz> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201112160904.23252.ptesarik@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo , linux-mm@kvack.org Cc: LKML , Vivek Goyal , surovegin@google.com, gthelen@google.com The phys_addr_t per_cpu_ptr_to_phys() function ignores the offset within a page, whenever not using a simple translation using __pa(). Without this patch /sys/devices/system/cpu/cpu*/crash_notes shows incorrect values, which breaks kdump. Other things may also be broken. Signed-off-by: Petr Tesarik diff --git a/mm/percpu.c b/mm/percpu.c index 3bb810a..1a1b5ac 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -998,6 +998,7 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr) bool in_first_chunk = false; unsigned long first_low, first_high; unsigned int cpu; + phys_addr_t page_addr; /* * The following test on unit_low/high isn't strictly @@ -1023,9 +1024,10 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr) if (!is_vmalloc_addr(addr)) return __pa(addr); else - return page_to_phys(vmalloc_to_page(addr)); + page_addr = page_to_phys(vmalloc_to_page(addr)); } else - return page_to_phys(pcpu_addr_to_page(addr)); + page_addr = page_to_phys(pcpu_addr_to_page(addr)); + return page_addr + offset_in_page(addr); } /** -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org