Re: Block: Trouble with kobject initialisation for blk_cmd_filter

From: Jens Axboe
Date: Tue Sep 09 2008 - 06:29:26 EST


On Fri, Sep 05 2008, Elias Oltmanns wrote:
> Hi all,
>
> current usage of the kobject in struct blk_cmd_filter is flawed. Doing
> # modprobe -r sd-mod && modprobe sd-mod
> while, for instance, a usb-stick is plugged in currently results in
> nasty warnings and a dump_stack(). Since blk_cmd_filter is embedded in
> struct request_queue, I don't see the need for a kobject anyway. What
> about the much simpler option of a struct attribute_group in this
> particular case?
>
> This would imply that the cmd_filter subdirectory would appear under
> sda/queue/ rather than sda/ (which is probably the right place) but,
> alas, we have to keep compatibility in mind. So I've made some changes
> to sysfs along the way in order to provide a legacy symlink. I'd have to
> seperate these two changes for submission but I wanted to know your
> opinion about it all first.
>
> Thinking about it now makes me wonder whether this is too much for a rc
> patch and whether we should just allocate the struct blk_cmd_filter
> dynamically and have done with it. Anyway, tell me what you think.

I think this patch is a step in the right direction, lets get rid of
that pesky kobject just for the cmdfilter. Can you resend the patch
_without_ the sysfs changes and link support? We haven't released a
kernel with cmd filter support yet, so we can change the location still
and not have to worry about compatability.

--
Jens Axboe

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