hi Kees Cook,
On 2020/5/11 AM 4:24, Kees Cook wrote:
> From: WeiXiong Liao <[email protected]>
>
> 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 <[email protected]>
> Link:
> https://lore.kernel.org/r/1585126506-18635-12-git-send-email-liaoweixi...@allwinnertech.com
> Signed-off-by: Kees Cook <[email protected]>
> ---
> 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. <hex_major><hex_minor> 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>:<minor> major and minor number of the device separated by a colon.
>
> +It accepts the following variants for MTD device:
> +
> +1. <device name> MTD device name. "pstore" is recommended.
> +#. <device number> 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 <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pstore_blk.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/bitops.h>
> +
> +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 <[email protected]>");
> +MODULE_DESCRIPTION("MTD backend for pstore/blk");
>
--
WeiXiong Liao
