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![Matthieu CASTET](/assets/img/avatar_default.png)
The current version on mtdoops erase first block of mtdoops partition at each boot if there is no oops stored in flash. This can wear the flash. When mtdoops start, find_next_position is called to find the next free entry in the circular buffer. But if the flash is erased, find_next_position don't find anything (maxcount == 0xffffffff) and start with the first entry after erasing it. The scanning that is done in find_next_position already track free/used entries. So if at the end of the scanning we don't find anything, we can start at the first entry and erased the entry only if it is marked as used. Most of this is implemented in mtdoops_inc_counter, so to avoid duplicating code, if we don't find anything we set position to -1. mtdoops_inc_counter with increment it, erase the entry if needed and start as before with nextpage = 0 and nextcount = 1). Also during the scan phase, we use the MTDOOPS_KERNMSG_MAGIC to detect corruped entries. Signed-off-by: Matthieu Castet <matthieu.castet@parrot@com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
451 lines
12 KiB
C
451 lines
12 KiB
C
/*
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* MTD Oops/Panic logger
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*
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* Copyright © 2007 Nokia Corporation. All rights reserved.
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*
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* Author: Richard Purdie <rpurdie@openedhand.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/console.h>
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#include <linux/vmalloc.h>
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#include <linux/workqueue.h>
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#include <linux/sched.h>
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#include <linux/wait.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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#include <linux/mtd/mtd.h>
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#include <linux/kmsg_dump.h>
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/* Maximum MTD partition size */
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#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
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#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
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#define MTDOOPS_HEADER_SIZE 8
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static unsigned long record_size = 4096;
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module_param(record_size, ulong, 0400);
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MODULE_PARM_DESC(record_size,
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"record size for MTD OOPS pages in bytes (default 4096)");
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static char mtddev[80];
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module_param_string(mtddev, mtddev, 80, 0400);
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MODULE_PARM_DESC(mtddev,
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"name or index number of the MTD device to use");
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static int dump_oops = 1;
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module_param(dump_oops, int, 0600);
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MODULE_PARM_DESC(dump_oops,
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"set to 1 to dump oopses, 0 to only dump panics (default 1)");
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static struct mtdoops_context {
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struct kmsg_dumper dump;
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int mtd_index;
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struct work_struct work_erase;
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struct work_struct work_write;
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struct mtd_info *mtd;
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int oops_pages;
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int nextpage;
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int nextcount;
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unsigned long *oops_page_used;
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void *oops_buf;
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} oops_cxt;
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static void mark_page_used(struct mtdoops_context *cxt, int page)
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{
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set_bit(page, cxt->oops_page_used);
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}
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static void mark_page_unused(struct mtdoops_context *cxt, int page)
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{
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clear_bit(page, cxt->oops_page_used);
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}
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static int page_is_used(struct mtdoops_context *cxt, int page)
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{
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return test_bit(page, cxt->oops_page_used);
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}
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static void mtdoops_erase_callback(struct erase_info *done)
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{
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wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
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wake_up(wait_q);
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}
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static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
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{
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struct mtd_info *mtd = cxt->mtd;
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u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
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u32 start_page = start_page_offset / record_size;
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u32 erase_pages = mtd->erasesize / record_size;
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struct erase_info erase;
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DECLARE_WAITQUEUE(wait, current);
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wait_queue_head_t wait_q;
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int ret;
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int page;
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init_waitqueue_head(&wait_q);
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erase.mtd = mtd;
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erase.callback = mtdoops_erase_callback;
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erase.addr = offset;
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erase.len = mtd->erasesize;
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erase.priv = (u_long)&wait_q;
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set_current_state(TASK_INTERRUPTIBLE);
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add_wait_queue(&wait_q, &wait);
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ret = mtd_erase(mtd, &erase);
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if (ret) {
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&wait_q, &wait);
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printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
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(unsigned long long)erase.addr,
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(unsigned long long)erase.len, mtddev);
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return ret;
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}
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schedule(); /* Wait for erase to finish. */
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remove_wait_queue(&wait_q, &wait);
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/* Mark pages as unused */
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for (page = start_page; page < start_page + erase_pages; page++)
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mark_page_unused(cxt, page);
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return 0;
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}
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static void mtdoops_inc_counter(struct mtdoops_context *cxt)
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{
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cxt->nextpage++;
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if (cxt->nextpage >= cxt->oops_pages)
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cxt->nextpage = 0;
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cxt->nextcount++;
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if (cxt->nextcount == 0xffffffff)
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cxt->nextcount = 0;
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if (page_is_used(cxt, cxt->nextpage)) {
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schedule_work(&cxt->work_erase);
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return;
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}
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printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
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cxt->nextpage, cxt->nextcount);
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}
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/* Scheduled work - when we can't proceed without erasing a block */
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static void mtdoops_workfunc_erase(struct work_struct *work)
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{
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struct mtdoops_context *cxt =
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container_of(work, struct mtdoops_context, work_erase);
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struct mtd_info *mtd = cxt->mtd;
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int i = 0, j, ret, mod;
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/* We were unregistered */
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if (!mtd)
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return;
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mod = (cxt->nextpage * record_size) % mtd->erasesize;
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if (mod != 0) {
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cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
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if (cxt->nextpage >= cxt->oops_pages)
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cxt->nextpage = 0;
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}
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while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
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badblock:
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printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
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cxt->nextpage * record_size);
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i++;
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cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
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if (cxt->nextpage >= cxt->oops_pages)
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cxt->nextpage = 0;
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if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
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printk(KERN_ERR "mtdoops: all blocks bad!\n");
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return;
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}
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}
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if (ret < 0) {
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printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
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return;
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}
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for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
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ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
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if (ret >= 0) {
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printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
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cxt->nextpage, cxt->nextcount);
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return;
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}
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if (ret == -EIO) {
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ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
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if (ret < 0 && ret != -EOPNOTSUPP) {
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printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
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return;
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}
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}
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goto badblock;
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}
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static void mtdoops_write(struct mtdoops_context *cxt, int panic)
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{
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struct mtd_info *mtd = cxt->mtd;
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size_t retlen;
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u32 *hdr;
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int ret;
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/* Add mtdoops header to the buffer */
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hdr = cxt->oops_buf;
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hdr[0] = cxt->nextcount;
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hdr[1] = MTDOOPS_KERNMSG_MAGIC;
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if (panic) {
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ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
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record_size, &retlen, cxt->oops_buf);
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if (ret == -EOPNOTSUPP) {
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printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
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return;
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}
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} else
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ret = mtd_write(mtd, cxt->nextpage * record_size,
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record_size, &retlen, cxt->oops_buf);
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if (retlen != record_size || ret < 0)
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printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
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cxt->nextpage * record_size, retlen, record_size, ret);
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mark_page_used(cxt, cxt->nextpage);
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memset(cxt->oops_buf, 0xff, record_size);
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mtdoops_inc_counter(cxt);
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}
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static void mtdoops_workfunc_write(struct work_struct *work)
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{
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struct mtdoops_context *cxt =
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container_of(work, struct mtdoops_context, work_write);
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mtdoops_write(cxt, 0);
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}
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static void find_next_position(struct mtdoops_context *cxt)
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{
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struct mtd_info *mtd = cxt->mtd;
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int ret, page, maxpos = 0;
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u32 count[2], maxcount = 0xffffffff;
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size_t retlen;
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for (page = 0; page < cxt->oops_pages; page++) {
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if (mtd_block_isbad(mtd, page * record_size))
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continue;
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/* Assume the page is used */
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mark_page_used(cxt, page);
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ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
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&retlen, (u_char *)&count[0]);
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if (retlen != MTDOOPS_HEADER_SIZE ||
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(ret < 0 && !mtd_is_bitflip(ret))) {
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printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
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page * record_size, retlen,
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MTDOOPS_HEADER_SIZE, ret);
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continue;
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}
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if (count[0] == 0xffffffff && count[1] == 0xffffffff)
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mark_page_unused(cxt, page);
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if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC)
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continue;
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if (maxcount == 0xffffffff) {
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maxcount = count[0];
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maxpos = page;
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} else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
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maxcount = count[0];
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maxpos = page;
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} else if (count[0] > maxcount && count[0] < 0xc0000000) {
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maxcount = count[0];
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maxpos = page;
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} else if (count[0] > maxcount && count[0] > 0xc0000000
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&& maxcount > 0x80000000) {
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maxcount = count[0];
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maxpos = page;
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}
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}
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if (maxcount == 0xffffffff) {
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cxt->nextpage = cxt->oops_pages - 1;
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cxt->nextcount = 0;
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}
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else {
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cxt->nextpage = maxpos;
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cxt->nextcount = maxcount;
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}
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mtdoops_inc_counter(cxt);
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}
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static void mtdoops_do_dump(struct kmsg_dumper *dumper,
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enum kmsg_dump_reason reason)
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{
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struct mtdoops_context *cxt = container_of(dumper,
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struct mtdoops_context, dump);
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/* Only dump oopses if dump_oops is set */
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if (reason == KMSG_DUMP_OOPS && !dump_oops)
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return;
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kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
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record_size - MTDOOPS_HEADER_SIZE, NULL);
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/* Panics must be written immediately */
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if (reason != KMSG_DUMP_OOPS)
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mtdoops_write(cxt, 1);
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/* For other cases, schedule work to write it "nicely" */
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schedule_work(&cxt->work_write);
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}
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static void mtdoops_notify_add(struct mtd_info *mtd)
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{
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struct mtdoops_context *cxt = &oops_cxt;
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u64 mtdoops_pages = div_u64(mtd->size, record_size);
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int err;
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if (!strcmp(mtd->name, mtddev))
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cxt->mtd_index = mtd->index;
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if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
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return;
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if (mtd->size < mtd->erasesize * 2) {
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printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
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mtd->index);
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return;
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}
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if (mtd->erasesize < record_size) {
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printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
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mtd->index);
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return;
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}
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if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
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printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
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mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
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return;
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}
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/* oops_page_used is a bit field */
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cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
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BITS_PER_LONG) * sizeof(unsigned long));
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if (!cxt->oops_page_used) {
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printk(KERN_ERR "mtdoops: could not allocate page array\n");
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return;
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}
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cxt->dump.max_reason = KMSG_DUMP_OOPS;
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cxt->dump.dump = mtdoops_do_dump;
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err = kmsg_dump_register(&cxt->dump);
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if (err) {
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printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
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vfree(cxt->oops_page_used);
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cxt->oops_page_used = NULL;
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return;
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}
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cxt->mtd = mtd;
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cxt->oops_pages = (int)mtd->size / record_size;
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find_next_position(cxt);
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printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
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}
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static void mtdoops_notify_remove(struct mtd_info *mtd)
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{
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struct mtdoops_context *cxt = &oops_cxt;
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if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
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return;
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if (kmsg_dump_unregister(&cxt->dump) < 0)
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printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
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cxt->mtd = NULL;
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flush_work(&cxt->work_erase);
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flush_work(&cxt->work_write);
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}
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static struct mtd_notifier mtdoops_notifier = {
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.add = mtdoops_notify_add,
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.remove = mtdoops_notify_remove,
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};
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static int __init mtdoops_init(void)
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{
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struct mtdoops_context *cxt = &oops_cxt;
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int mtd_index;
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char *endp;
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if (strlen(mtddev) == 0) {
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printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
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return -EINVAL;
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}
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if ((record_size & 4095) != 0) {
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printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
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return -EINVAL;
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}
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if (record_size < 4096) {
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printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
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return -EINVAL;
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}
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/* Setup the MTD device to use */
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cxt->mtd_index = -1;
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mtd_index = simple_strtoul(mtddev, &endp, 0);
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if (*endp == '\0')
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cxt->mtd_index = mtd_index;
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cxt->oops_buf = vmalloc(record_size);
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if (!cxt->oops_buf) {
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printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
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return -ENOMEM;
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}
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memset(cxt->oops_buf, 0xff, record_size);
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INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
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INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
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register_mtd_user(&mtdoops_notifier);
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return 0;
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}
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static void __exit mtdoops_exit(void)
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{
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struct mtdoops_context *cxt = &oops_cxt;
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unregister_mtd_user(&mtdoops_notifier);
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vfree(cxt->oops_buf);
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vfree(cxt->oops_page_used);
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}
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module_init(mtdoops_init);
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module_exit(mtdoops_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
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MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
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