From: Kees Cook <keescook@chromium.org>
To: Christoph Hellwig <hch@lst.de>
Cc: WeiXiong Liao <gmpy.liaowx@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: use case for register_pstore_blk?
Date: Wed, 7 Oct 2020 00:13:27 -0700 [thread overview]
Message-ID: <202010070007.8FF59EC42@keescook> (raw)
In-Reply-To: <20201006155220.GA11668@lst.de>
On Tue, Oct 06, 2020 at 05:52:20PM +0200, Christoph Hellwig wrote:
> Hi WeiXiong, hi Kees,
>
> what is the use case for the code added in commit 17639f67c1d6
> ("pstore/blk: Introduce backend for block devices").
>
> This still doesn't have a user, and the API looks really odd to me.
pstore is a beast. :) The API is there so that a blk device can declare
its direct support of pstore (specifically, to provide a panic_write
handler).
The MTD device does this, but yes, that's a good point, there isn't a
blk device user of that entry point yet.
> By our normal kernel rules we should not add new exports without
> users and this should probably be reverted for the 5.9 release.
I don't want to revert the entire patch (I'm still using
__register_pstore_blk by way of pstore/blk's "best_effort" option), but
I wouldn't object to something like this:
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index fcd5563dde06..e0fe21e2cf34 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -419,27 +419,6 @@ static int __register_pstore_blk(struct pstore_blk_info *info)
return ret;
}
-/**
- * register_pstore_blk() - register block device to pstore/blk
- *
- * @info: details on the desired block device interface
- *
- * Return:
- * * 0 - OK
- * * Others - something error.
- */
-int register_pstore_blk(struct pstore_blk_info *info)
-{
- int ret;
-
- mutex_lock(&pstore_blk_lock);
- ret = __register_pstore_blk(info);
- mutex_unlock(&pstore_blk_lock);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(register_pstore_blk);
-
static void __unregister_pstore_blk(unsigned int major)
{
struct pstore_device_info dev = { .read = psblk_generic_blk_read };
@@ -454,19 +433,6 @@ static void __unregister_pstore_blk(unsigned int major)
}
}
-/**
- * unregister_pstore_blk() - unregister block device from pstore/blk
- *
- * @major: the major device number of device
- */
-void unregister_pstore_blk(unsigned int major)
-{
- mutex_lock(&pstore_blk_lock);
- __unregister_pstore_blk(major);
- mutex_unlock(&pstore_blk_lock);
-}
-EXPORT_SYMBOL_GPL(unregister_pstore_blk);
-
/* get information of pstore/blk */
int pstore_blk_get_config(struct pstore_blk_config *info)
{
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
index 61e914522b01..2bf07d20ce43 100644
--- a/include/linux/pstore_blk.h
+++ b/include/linux/pstore_blk.h
@@ -46,9 +46,6 @@ struct pstore_blk_info {
sector_t start_sect;
};
-int register_pstore_blk(struct pstore_blk_info *info);
-void unregister_pstore_blk(unsigned int major);
-
/**
* struct pstore_device_info - back-end pstore/blk driver structure.
*
--
Kees Cook
next prev parent reply other threads:[~2020-10-07 7:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 15:52 use case for register_pstore_blk? Christoph Hellwig
2020-10-07 7:13 ` Kees Cook [this message]
2020-10-07 7:37 ` Christoph Hellwig
2020-10-07 7:55 ` Christoph Hellwig
2020-10-07 8:37 ` Christoph Hellwig
2020-10-07 18:40 ` Kees Cook
2020-10-07 18:42 ` Christoph Hellwig
2020-10-07 19:17 ` Kees Cook
2020-10-12 7:02 ` Christoph Hellwig
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