From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755138AbbGPIy2 (ORCPT ); Thu, 16 Jul 2015 04:54:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38577 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753731AbbGPIsG (ORCPT ); Thu, 16 Jul 2015 04:48:06 -0400 From: Baoquan He To: linux-kernel@vger.kernel.org, ncroxon@redhat.com, dyoung@redhat.com, mhuang@redhat.com Cc: Baoquan He Subject: [RHEL6.8 Patch 06/19] vmcore: clean up read_vmcore() Date: Thu, 16 Jul 2015 16:47:04 +0800 Message-Id: <1437036437-25408-10-git-send-email-bhe@redhat.com> In-Reply-To: <1437036437-25408-1-git-send-email-bhe@redhat.com> References: <1437036437-25408-1-git-send-email-bhe@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Resolves: bz1097904 https://bugzilla.redhat.com/show_bug.cgi?id=1097904 This is back ported from upstream directly. commit b27eb186608c89ef0979ae47c649859ceaa1b2e7 Author: HATAYAMA Daisuke Date: Wed Jul 3 15:02:13 2013 -0700 vmcore: clean up read_vmcore() Rewrite part of read_vmcore() that reads objects in vmcore_list in the same way as part reading ELF headers, by which some duplicated and redundant codes are removed. Signed-off-by: HATAYAMA Daisuke Acked-by: Vivek Goyal Cc: KOSAKI Motohiro Cc: Atsushi Kumagai Cc: Lisa Mitchell Cc: Zhang Yanfei Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Baoquan He --- fs/proc/vmcore.c | 68 +++++++++++++++++--------------------------------------- 1 file changed, 20 insertions(+), 48 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 1def40a..861956c 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -114,27 +114,6 @@ static ssize_t read_from_oldmem(char *buf, size_t count, return read; } -/* Maps vmcore file offset to respective physical address in memroy. */ -static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list, - struct vmcore **m_ptr) -{ - struct vmcore *m; - u64 paddr; - - list_for_each_entry(m, vc_list, list) { - u64 start, end; - start = m->offset; - end = m->offset + m->size - 1; - if (offset >= start && offset <= end) { - paddr = m->paddr + offset - start; - *m_ptr = m; - return paddr; - } - } - *m_ptr = NULL; - return 0; -} - /* Read from the ELF header and then the crash dump. On error, negative value is * returned otherwise number of bytes read are returned. */ @@ -143,8 +122,8 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer, { ssize_t acc = 0, tmp; size_t tsz; - u64 start, nr_bytes; - struct vmcore *curr_m = NULL; + u64 start; + struct vmcore *m = NULL; if (buflen == 0 || *fpos >= vmcore_size) return 0; @@ -170,33 +149,26 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer, return acc; } - start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m); - if (!curr_m) - return -EINVAL; - - while (buflen) { - tsz = min_t(size_t, buflen, PAGE_SIZE - (start & ~PAGE_MASK)); - - /* Calculate left bytes in current memory segment. */ - nr_bytes = (curr_m->size - (start - curr_m->paddr)); - if (tsz > nr_bytes) - tsz = nr_bytes; - - tmp = read_from_oldmem(buffer, tsz, &start, 1); - if (tmp < 0) - return tmp; - buflen -= tsz; - *fpos += tsz; - buffer += tsz; - acc += tsz; - if (start >= (curr_m->paddr + curr_m->size)) { - if (curr_m->list.next == &vmcore_list) - return acc; /*EOF*/ - curr_m = list_entry(curr_m->list.next, - struct vmcore, list); - start = curr_m->paddr; + list_for_each_entry(m, &vmcore_list, list) { + if (*fpos < m->offset + m->size) { + tsz = m->offset + m->size - *fpos; + if (buflen < tsz) + tsz = buflen; + start = m->paddr + *fpos - m->offset; + tmp = read_from_oldmem(buffer, tsz, &start, 1); + if (tmp < 0) + return tmp; + buflen -= tsz; + *fpos += tsz; + buffer += tsz; + acc += tsz; + + /* leave now if filled buffer already */ + if (buflen == 0) + return acc; } } + return acc; } -- 2.1.0