From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8817C54E4B for ; Mon, 11 May 2020 09:01:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87742207DD for ; Mon, 11 May 2020 09:01:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729226AbgEKJB3 (ORCPT ); Mon, 11 May 2020 05:01:29 -0400 Received: from smtp2207-205.mail.aliyun.com ([121.197.207.205]:33233 "EHLO smtp2207-205.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725790AbgEKJB2 (ORCPT ); Mon, 11 May 2020 05:01:28 -0400 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.07436282|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_alarm|0.00693051-0.00184614-0.991223;FP=0|0|0|0|0|-1|-1|-1;HT=e02c03305;MF=liaoweixiong@allwinnertech.com;NM=1;PH=DS;RN=16;RT=16;SR=0;TI=SMTPD_---.HWoBb8y_1589187676; Received: from 172.16.10.102(mailfrom:liaoweixiong@allwinnertech.com fp:SMTPD_---.HWoBb8y_1589187676) by smtp.aliyun-inc.com(10.147.41.138); Mon, 11 May 2020 17:01:17 +0800 Subject: Re: [PATCH v7 17/18] mtd: Support kmsg dumper based on pstore/blk To: Kees Cook Cc: Anton Vorontsov , Colin Cross , Tony Luck , Jonathan Corbet , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Rob Herring , Pavel Tatashin , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org References: <20200510202436.63222-1-keescook@chromium.org> <20200510202436.63222-18-keescook@chromium.org> From: WeiXiong Liao Message-ID: <59ef2812-93ad-9f8c-81cc-458128a6fb46@allwinnertech.com> Date: Mon, 11 May 2020 17:01:26 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20200510202436.63222-18-keescook@chromium.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org hi Kees Cook, On 2020/5/11 AM 4:24, Kees Cook wrote: > From: WeiXiong Liao > > This introduces mtdpstore, which is similar to mtdoops but more > powerful. It uses pstore/blk, and aims to store panic and oops logs to > a flash partition, where pstore can later read back and present as files > in the mounted pstore filesystem. > > To make mtdpstore work, the "blkdev" of pstore/blk should be set > as MTD device name or MTD device number. For more details, see > Documentation/admin-guide/pstore-blk.rst > > This solves a number of issues: > - Work duplication: both of pstore and mtdoops do the same job storing > panic/oops log. They have very similar logic, registering to kmsg > dumper and storing logs to several chunks one by one. > - Layer violations: drivers should provides methods instead of polices. > MTD should provide read/write/erase operations, and allow a higher > level drivers to provide the chunk management, kmsg dump > configuration, etc. > - Missing features: pstore provides many additional features, including > presenting the logs as files, logging dump time and count, and > supporting other frontends like pmsg, console, etc. > > Signed-off-by: WeiXiong Liao > Link: https://lore.kernel.org/r/1585126506-18635-12-git-send-email-liaoweixiong@allwinnertech.com > Signed-off-by: Kees Cook > --- > Documentation/admin-guide/pstore-blk.rst | 9 +- > drivers/mtd/Kconfig | 10 + > drivers/mtd/Makefile | 1 + > drivers/mtd/mtdpstore.c | 564 +++++++++++++++++++++++ > 4 files changed, 582 insertions(+), 2 deletions(-) > create mode 100644 drivers/mtd/mtdpstore.c > > diff --git a/Documentation/admin-guide/pstore-blk.rst b/Documentation/admin-guide/pstore-blk.rst > index d45341e55e82..296d5027787a 100644 > --- a/Documentation/admin-guide/pstore-blk.rst > +++ b/Documentation/admin-guide/pstore-blk.rst > @@ -43,9 +43,9 @@ blkdev > ~~~~~~ > > The block device to use. Most of the time, it is a partition of block device. > -It's required for pstore/blk. > +It's required for pstore/blk. It is also used for MTD device. > > -It accepts the following variants: > +It accepts the following variants for block device: > > 1. device number in hexadecimal represents itself; no > leading 0x, for example b302. > @@ -64,6 +64,11 @@ It accepts the following variants: > partition with a known unique id. > #. : major and minor number of the device separated by a colon. > > +It accepts the following variants for MTD device: > + > +1. MTD device name. "pstore" is recommended. > +#. MTD device number. > + > kmsg_size > ~~~~~~~~~ > > diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig > index 42d401ea60ee..6ddab796216d 100644 > --- a/drivers/mtd/Kconfig > +++ b/drivers/mtd/Kconfig > @@ -170,6 +170,16 @@ config MTD_OOPS > buffer in a flash partition where it can be read back at some > later point. > > +config MTD_PSTORE > + tristate "Log panic/oops to an MTD buffer based on pstore" > + depends on PSTORE_BLK > + help > + This enables panic and oops messages to be logged to a circular > + buffer in a flash partition where it can be read back as files after > + mounting pstore filesystem. > + > + If unsure, say N. > + > config MTD_SWAP > tristate "Swap on MTD device support" > depends on MTD && SWAP > diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile > index 56cc60ccc477..593d0593a038 100644 > --- a/drivers/mtd/Makefile > +++ b/drivers/mtd/Makefile > @@ -20,6 +20,7 @@ obj-$(CONFIG_RFD_FTL) += rfd_ftl.o > obj-$(CONFIG_SSFDC) += ssfdc.o > obj-$(CONFIG_SM_FTL) += sm_ftl.o > obj-$(CONFIG_MTD_OOPS) += mtdoops.o > +obj-$(CONFIG_MTD_PSTORE) += mtdpstore.o > obj-$(CONFIG_MTD_SWAP) += mtdswap.o > > nftl-objs := nftlcore.o nftlmount.o > diff --git a/drivers/mtd/mtdpstore.c b/drivers/mtd/mtdpstore.c > new file mode 100644 > index 000000000000..ce6da4d04864 > --- /dev/null > +++ b/drivers/mtd/mtdpstore.c > @@ -0,0 +1,564 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#define dev_fmt(fmt) "mtdoops-pstore: " fmt > + > +#include > +#include > +#include > +#include > +#include > + > +static struct mtdpstore_context { > + int index; > + struct pstore_blk_config info; > + struct pstore_device_info dev; > + struct mtd_info *mtd; > + unsigned long *rmmap; /* removed bit map */ > + unsigned long *usedmap; /* used bit map */ > + /* > + * used for panic write > + * As there are no block_isbad for panic case, we should keep this > + * status before panic to ensure panic_write not failed. > + */ > + unsigned long *badmap; /* bad block bit map */ > +} oops_cxt; > + > +static int mtdpstore_block_isbad(struct mtdpstore_context *cxt, loff_t off) > +{ > + int ret; > + struct mtd_info *mtd = cxt->mtd; > + u64 blknum = div_u64(off, mtd->erasesize); > + > + if (test_bit(blknum, cxt->badmap)) > + return true; > + ret = mtd_block_isbad(mtd, off); > + if (ret < 0) { > + dev_err(&mtd->dev, "mtd_block_isbad failed, aborting\n"); > + return ret; > + } else if (ret > 0) { > + set_bit(blknum, cxt->badmap); > + return true; > + } > + return false; > +} > + > +static inline int mtdpstore_panic_block_isbad(struct mtdpstore_context *cxt, > + loff_t off) > +{ > + struct mtd_info *mtd = cxt->mtd; > + u64 blknum = div_u64(off, mtd->erasesize); > + > + return test_bit(blknum, cxt->badmap); > +} > + > +static inline void mtdpstore_mark_used(struct mtdpstore_context *cxt, > + loff_t off) > +{ > + struct mtd_info *mtd = cxt->mtd; > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + > + dev_dbg(&mtd->dev, "mark zone %llu used\n", zonenum); > + set_bit(zonenum, cxt->usedmap); > +} > + > +static inline void mtdpstore_mark_unused(struct mtdpstore_context *cxt, > + loff_t off) > +{ > + struct mtd_info *mtd = cxt->mtd; > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + > + dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum); > + clear_bit(zonenum, cxt->usedmap); > +} > + > +static inline void mtdpstore_block_mark_unused(struct mtdpstore_context *cxt, > + loff_t off) > +{ > + struct mtd_info *mtd = cxt->mtd; > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + u32 zonecnt = cxt->mtd->erasesize / cxt->info.kmsg_size; > + > + while (zonecnt > 0) { > + dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum); > + clear_bit(zonenum, cxt->usedmap); > + zonenum++; > + zonecnt--; > + } > +} > + > +static inline int mtdpstore_is_used(struct mtdpstore_context *cxt, loff_t off) > +{ > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + u64 blknum = div_u64(off, cxt->mtd->erasesize); > + > + if (test_bit(blknum, cxt->badmap)) > + return true; > + return test_bit(zonenum, cxt->usedmap); > +} > + > +static int mtdpstore_block_is_used(struct mtdpstore_context *cxt, > + loff_t off) > +{ > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + u32 zonecnt = cxt->mtd->erasesize / cxt->info.kmsg_size; > + > + while (zonecnt > 0) { > + if (test_bit(zonenum, cxt->usedmap)) > + return true; > + zonenum++; > + zonecnt--; > + } > + return false; > +} > + > +static int mtdpstore_is_empty(struct mtdpstore_context *cxt, char *buf, > + size_t size) > +{ > + struct mtd_info *mtd = cxt->mtd; > + size_t sz; > + int i; > + > + sz = min_t(uint32_t, size, mtd->writesize / 4); > + for (i = 0; i < sz; i++) { > + if (buf[i] != (char)0xFF) > + return false; > + } > + return true; > +} > + > +static void mtdpstore_mark_removed(struct mtdpstore_context *cxt, loff_t off) > +{ > + struct mtd_info *mtd = cxt->mtd; > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + > + dev_dbg(&mtd->dev, "mark zone %llu removed\n", zonenum); > + set_bit(zonenum, cxt->rmmap); > +} > + > +static void mtdpstore_block_clear_removed(struct mtdpstore_context *cxt, > + loff_t off) > +{ > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + u32 zonecnt = cxt->mtd->erasesize / cxt->info.kmsg_size; > + > + while (zonecnt > 0) { > + clear_bit(zonenum, cxt->rmmap); > + zonenum++; > + zonecnt--; > + } > +} > + > +static int mtdpstore_block_is_removed(struct mtdpstore_context *cxt, > + loff_t off) > +{ > + u64 zonenum = div_u64(off, cxt->info.kmsg_size); > + u32 zonecnt = cxt->mtd->erasesize / cxt->info.kmsg_size; > + > + while (zonecnt > 0) { > + if (test_bit(zonenum, cxt->rmmap)) > + return true; > + zonenum++; > + zonecnt--; > + } > + return false; > +} > + > +static int mtdpstore_erase_do(struct mtdpstore_context *cxt, loff_t off) > +{ > + struct mtd_info *mtd = cxt->mtd; > + struct erase_info erase; > + int ret; > + > + dev_dbg(&mtd->dev, "try to erase off 0x%llx\n", off); > + erase.len = cxt->mtd->erasesize; > + erase.addr = off; > + ret = mtd_erase(cxt->mtd, &erase); > + if (!ret) > + mtdpstore_block_clear_removed(cxt, off); > + else > + dev_err(&mtd->dev, "erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", > + (unsigned long long)erase.addr, > + (unsigned long long)erase.len, cxt->info.device); > + return ret; > +} > + > +/* > + * called while removing file > + * > + * Avoiding over erasing, do erase block only when the whole block is unused. > + * If the block contains valid log, do erase lazily on flush_removed() when > + * unregister. > + */ > +static ssize_t mtdpstore_erase(size_t size, loff_t off) > +{ > + struct mtdpstore_context *cxt = &oops_cxt; > + > + if (mtdpstore_block_isbad(cxt, off)) > + return -EIO; > + > + mtdpstore_mark_unused(cxt, off); > + > + /* If the block still has valid data, mtdpstore do erase lazily */ > + if (likely(mtdpstore_block_is_used(cxt, off))) { > + mtdpstore_mark_removed(cxt, off); > + return 0; > + } > + > + /* all zones are unused, erase it */ > + off = ALIGN_DOWN(off, cxt->mtd->erasesize); > + return mtdpstore_erase_do(cxt, off); > +} > + > +/* > + * What is security for mtdpstore? > + * As there is no erase for panic case, we should ensure at least one zone > + * is writable. Otherwise, panic write will fail. > + * If zone is used, write operation will return -ENOMSG, which means that > + * pstore/blk will try one by one until gets an empty zone. So, it is not > + * needed to ensure the next zone is empty, but at least one. > + */ > +static int mtdpstore_security(struct mtdpstore_context *cxt, loff_t off) > +{ > + int ret = 0, i; > + struct mtd_info *mtd = cxt->mtd; > + u32 zonenum = (u32)div_u64(off, cxt->info.kmsg_size); > + u32 zonecnt = (u32)div_u64(cxt->mtd->size, cxt->info.kmsg_size); > + u32 blkcnt = (u32)div_u64(cxt->mtd->size, cxt->mtd->erasesize); > + u32 erasesize = cxt->mtd->erasesize; > + > + for (i = 0; i < zonecnt; i++) { > + u32 num = (zonenum + i) % zonecnt; > + > + /* found empty zone */ > + if (!test_bit(num, cxt->usedmap)) > + return 0; > + } > + > + /* If there is no any empty zone, we have no way but to do erase */ > + off = ALIGN_DOWN(off, erasesize); > + while (blkcnt--) { > + div64_u64_rem(off + erasesize, cxt->mtd->size, (u64 *)&off); > + > + if (mtdpstore_block_isbad(cxt, off)) > + continue; > + > + ret = mtdpstore_erase_do(cxt, off); > + if (!ret) { > + mtdpstore_block_mark_unused(cxt, off); > + break; > + } > + } > + > + if (ret) > + dev_err(&mtd->dev, "all blocks bad!\n"); > + dev_dbg(&mtd->dev, "end security\n"); > + return ret; > +} > + > +static ssize_t mtdpstore_write(const char *buf, size_t size, loff_t off) > +{ > + struct mtdpstore_context *cxt = &oops_cxt; > + struct mtd_info *mtd = cxt->mtd; > + size_t retlen; > + int ret; > + > + if (mtdpstore_block_isbad(cxt, off)) > + return -ENOMSG; > + > + /* zone is used, please try next one */ > + if (mtdpstore_is_used(cxt, off)) > + return -ENOMSG; > + > + dev_dbg(&mtd->dev, "try to write off 0x%llx size %zu\n", off, size); > + ret = mtd_write(cxt->mtd, off, size, &retlen, (u_char *)buf); > + if (ret < 0 || retlen != size) { > + dev_err(&mtd->dev, "write failure at %lld (%zu of %zu written), err %d\n", > + off, retlen, size, ret); > + return -EIO; > + } > + mtdpstore_mark_used(cxt, off); > + > + mtdpstore_security(cxt, off); > + return retlen; > +} > + > +static inline bool mtdpstore_is_io_error(int ret) > +{ > + return ret < 0 && !mtd_is_bitflip(ret) && !mtd_is_eccerr(ret); > +} > + > +/* > + * All zones will be read as pstore/blk will read zone one by one when do > + * recover. > + */ > +static ssize_t mtdpstore_read(char *buf, size_t size, loff_t off) > +{ > + struct mtdpstore_context *cxt = &oops_cxt; > + struct mtd_info *mtd = cxt->mtd; > + size_t retlen, done; > + int ret; > + > + if (mtdpstore_block_isbad(cxt, off)) > + return -ENOMSG; > + > + dev_dbg(&mtd->dev, "try to read off 0x%llx size %zu\n", off, size); > + for (done = 0, retlen = 0; done < size; done += retlen) { > + retlen = 0; > + > + ret = mtd_read(cxt->mtd, off + done, size - done, &retlen, > + (u_char *)buf + done); > + if (mtdpstore_is_io_error(ret)) { > + dev_err(&mtd->dev, "read failure at %lld (%zu of %zu read), err %d\n", > + off + done, retlen, size - done, ret); > + /* the zone may be broken, try next one */ > + return -ENOMSG; > + } > + > + /* > + * ECC error. The impact on log data is so small. Maybe we can > + * still read it and try to understand. So mtdpstore just hands > + * over what it gets and user can judge whether the data is > + * valid or not. > + */ > + if (mtd_is_eccerr(ret)) { > + dev_err(&mtd->dev, "ecc error at %lld (%zu of %zu read), err %d\n", > + off + done, retlen, size - done, ret); > + /* driver may not set retlen when ecc error */ > + retlen = retlen == 0 ? size - done : retlen; > + } > + } > + > + if (mtdpstore_is_empty(cxt, buf, size)) > + mtdpstore_mark_unused(cxt, off); > + else > + mtdpstore_mark_used(cxt, off); > + > + mtdpstore_security(cxt, off); > + return retlen; > +} > + > +static ssize_t mtdpstore_panic_write(const char *buf, size_t size, loff_t off) > +{ > + struct mtdpstore_context *cxt = &oops_cxt; > + struct mtd_info *mtd = cxt->mtd; > + size_t retlen; > + int ret; > + > + if (mtdpstore_panic_block_isbad(cxt, off)) > + return -ENOMSG; > + > + /* zone is used, please try next one */ > + if (mtdpstore_is_used(cxt, off)) > + return -ENOMSG; > + > + ret = mtd_panic_write(cxt->mtd, off, size, &retlen, (u_char *)buf); > + if (ret < 0 || size != retlen) { > + dev_err(&mtd->dev, "panic write failure at %lld (%zu of %zu read), err %d\n", > + off, retlen, size, ret); > + return -EIO; > + } > + mtdpstore_mark_used(cxt, off); > + > + return retlen; > +} > + > +static void mtdpstore_notify_add(struct mtd_info *mtd) > +{ > + int ret; > + struct mtdpstore_context *cxt = &oops_cxt; > + struct pstore_blk_config *info = &cxt->info; > + unsigned long longcnt; > + > + if (!strcmp(mtd->name, info->device)) > + cxt->index = mtd->index; > + > + if (mtd->index != cxt->index || cxt->index < 0) > + return; > + > + dev_dbg(&mtd->dev, "found matching MTD device %s\n", mtd->name); > + > + if (mtd->size < info->kmsg_size * 2) { > + dev_err(&mtd->dev, "MTD partition %d not big enough\n", > + mtd->index); > + return; > + } > + /* > + * kmsg_size must be aligned to 4096 Bytes, which is limited by > + * psblk. The default value of kmsg_size is 64KB. If kmsg_size > + * is larger than erasesize, some errors will occur since mtdpsotre > + * is designed on it. > + */ > + if (mtd->erasesize < info->kmsg_size) { > + dev_err(&mtd->dev, "eraseblock size of MTD partition %d too small\n", > + mtd->index); > + return; > + } > + if (unlikely(info->kmsg_size % mtd->writesize)) { > + dev_err(&mtd->dev, "record size %lu KB must align to write size %d KB\n", > + info->kmsg_size / 1024, > + mtd->writesize / 1024); > + return; > + } > + > + longcnt = BITS_TO_LONGS(div_u64(mtd->size, info->kmsg_size)); > + cxt->rmmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); > + cxt->usedmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); > + > + longcnt = BITS_TO_LONGS(div_u64(mtd->size, mtd->erasesize)); > + cxt->badmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); > + > + cxt->dev.total_size = mtd->size; > + /* just support dmesg right now */ > + cxt->dev.flags = PSTORE_FLAGS_DMESG; > + cxt->dev.read = mtdpstore_read; > + cxt->dev.write = mtdpstore_write; > + cxt->dev.erase = mtdpstore_erase; > + cxt->dev.panic_write = mtdpstore_panic_write; > + > + ret = register_pstore_device(&cxt->dev); > + if (ret) { > + dev_err(&mtd->dev, "mtd%d register to psblk failed\n", > + mtd->index); > + return; > + } > + cxt->mtd = mtd; > + dev_info(&mtd->dev, "Attached to MTD device %d\n", mtd->index); > +} > + > +static int mtdpstore_flush_removed_do(struct mtdpstore_context *cxt, > + loff_t off, size_t size) > +{ > + struct mtd_info *mtd = cxt->mtd; > + u_char *buf; > + int ret; > + size_t retlen; > + struct erase_info erase; > + > + buf = kmalloc(mtd->erasesize, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; > + > + /* 1st. read to cache */ > + ret = mtd_read(mtd, off, mtd->erasesize, &retlen, buf); > + if (mtdpstore_is_io_error(ret)) > + goto free; > + > + /* 2nd. erase block */ > + erase.len = mtd->erasesize; > + erase.addr = off; > + ret = mtd_erase(mtd, &erase); > + if (ret) > + goto free; > + > + /* 3rd. write back */ > + while (size) { > + unsigned int zonesize = cxt->info.kmsg_size; > + > + /* there is valid data on block, write back */ > + if (mtdpstore_is_used(cxt, off)) { > + ret = mtd_write(mtd, off, zonesize, &retlen, buf); > + if (ret) > + dev_err(&mtd->dev, "write failure at %lld (%zu of %u written), err %d\n", > + off, retlen, zonesize, ret); > + } > + > + off += zonesize; > + size -= min_t(unsigned int, zonesize, size); > + } > + > +free: > + kfree(buf); > + return ret; > +} > + > +/* > + * What does mtdpstore_flush_removed() do? > + * When user remove any log file on pstore filesystem, mtdpstore should do > + * something to ensure log file removed. If the whole block is no longer used, > + * it's nice to erase the block. However if the block still contains valid log, > + * what mtdpstore can do is to erase and write the valid log back. > + */ > +static int mtdpstore_flush_removed(struct mtdpstore_context *cxt) > +{ > + struct mtd_info *mtd = cxt->mtd; > + int ret; > + loff_t off; > + u32 blkcnt = (u32)div_u64(mtd->size, mtd->erasesize); > + > + for (off = 0; blkcnt > 0; blkcnt--, off += mtd->erasesize) { > + ret = mtdpstore_block_isbad(cxt, off); > + if (ret) > + continue; > + > + ret = mtdpstore_block_is_removed(cxt, off); > + if (!ret) > + continue; > + > + ret = mtdpstore_flush_removed_do(cxt, off, mtd->erasesize); > + if (ret) > + return ret; > + } > + return 0; > +} > + > +static void mtdpstore_notify_remove(struct mtd_info *mtd) > +{ > + struct mtdpstore_context *cxt = &oops_cxt; > + > + if (mtd->index != cxt->index || cxt->index < 0) > + return; > + > + mtdpstore_flush_removed(cxt); > + > + unregister_pstore_device(&cxt->dev); > + kfree(cxt->badmap); > + kfree(cxt->usedmap); > + kfree(cxt->rmmap); > + cxt->mtd = NULL; > + cxt->index = -1; > +} > + > +static struct mtd_notifier mtdpstore_notifier = { > + .add = mtdpstore_notify_add, > + .remove = mtdpstore_notify_remove, > +}; > + > +static int __init mtdpstore_init(void) > +{ > + int ret; > + struct mtdpstore_context *cxt = &oops_cxt; > + struct mtd_info *mtd = cxt->mtd; > + struct pstore_blk_config *info = &cxt->info; > + > + ret = pstore_blk_get_config(info); > + if (unlikely(ret)) > + return ret; > + > + if (strlen(info->device) == 0) { > + dev_err(&mtd->dev, "mtd device must be supplied\n"); mtd is NULL here, "mtd->dev" leads to error. > + return -EINVAL; > + } > + if (!info->kmsg_size) { > + dev_err(&mtd->dev, "no backend enabled\n"); Also here. > + return -EINVAL; > + } > + > + /* Setup the MTD device to use */ > + ret = kstrtoint((char *)info->device, 0, &cxt->index); > + if (ret) > + cxt->index = -1; > + > + register_mtd_user(&mtdpstore_notifier); > + return 0; > +} > +module_init(mtdpstore_init); > + > +static void __exit mtdpstore_exit(void) > +{ > + unregister_mtd_user(&mtdpstore_notifier); > +} > +module_exit(mtdpstore_exit); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("WeiXiong Liao "); > +MODULE_DESCRIPTION("MTD backend for pstore/blk"); > -- WeiXiong Liao