From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Xiaoming Ni <nixiaoming@huawei.com>
Cc: wangle6@huawei.com, vigneshr@ti.com, richard@nod.at,
houtao1@huawei.com, linux-kernel@vger.kernel.org,
linux-mtd@lists.infradead.org, zhangweimin12@huawei.com,
gregkh@linuxfoundation.org, stable@kernel.org,
yebin10@huawei.com
Subject: Re: [PATCH v3] mtd:fix cache_state to avoid writing to bad blocks repeatedly
Date: Mon, 30 Mar 2020 15:52:22 +0200 [thread overview]
Message-ID: <20200330155222.20359293@xps13> (raw)
In-Reply-To: <1585575925-84017-1-git-send-email-nixiaoming@huawei.com>
Hi Xiaoming,
Xiaoming Ni <nixiaoming@huawei.com> wrote on Mon, 30 Mar 2020 21:45:25
+0800:
> The function call process is as follows:
> mtd_blktrans_work()
> while (1)
> do_blktrans_request()
> mtdblock_writesect()
> do_cached_write()
> write_cached_data() /*if cache_state is STATE_DIRTY*/
> erase_write()
>
> write_cached_data() returns failure without modifying cache_state
> and cache_offset. So when do_cached_write() is called again,
> write_cached_data() will be called again to perform erase_write()
> on the same cache_offset.
>
> But if this cache_offset points to a bad block, erase_write() will
> always return -EIO. Writing to this mtdblk is equivalent to losing
> the current data, and repeatedly writing to the bad block.
>
> Repeatedly writing a bad block has no real benefits,
> but brings some negative effects:
> 1 Lost subsequent data
> 2 Loss of flash device life
> 3 erase_write() bad blocks are very time-consuming. For example:
> the function do_erase_oneblock() in chips/cfi_cmdset_0020.c or
> chips/cfi_cmdset_0002.c may take more than 20 seconds to return
>
> Therefore, when erase_write() returns -EIO in write_cached_data(),
> clear cache_state to avoid writing to bad blocks repeatedly.
>
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: stable@vger.kernel.org
Still missing:
* Fixes: tag
* Wrong title prefix
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2020-03-30 13:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 13:45 [PATCH v3] mtd:fix cache_state to avoid writing to bad blocks repeatedly Xiaoming Ni
2020-03-30 13:52 ` Miquel Raynal [this message]
2020-03-30 14:25 ` Xiaoming Ni
2020-03-30 14:55 ` Miquel Raynal
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200330155222.20359293@xps13 \
--to=miquel.raynal@bootlin.com \
--cc=gregkh@linuxfoundation.org \
--cc=houtao1@huawei.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mtd@lists.infradead.org \
--cc=nixiaoming@huawei.com \
--cc=richard@nod.at \
--cc=stable@kernel.org \
--cc=vigneshr@ti.com \
--cc=wangle6@huawei.com \
--cc=yebin10@huawei.com \
--cc=zhangweimin12@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).