Re: [PATCH] pktcdvd: added sysfs interface + bio write queue handling fix

[Greg KH <greg@kroah.com>]

On Sat, Sep 09, 2006 at 08:11:56PM +0200, Thomas Maier wrote:
> Hello,
> 
> >> +    write_queue_size  (r)  Contains the size of the bio write
> >> +                           queue.
> ...
> >> +    mapped_to              Symbolic link to mapped block device
> >> +                           in the /sys/block tree.
> >
> > Shouldn't this whole thing be in /sys/class/ instead of /sys/block/ ?
> 
> Don't know. I thought, the pktcdvd is a block driver, so put
> the control files into /sys/block ..
> Is /sys/class better? If yes, where to put it?

Use /sys/class/pktcdvd/ and use struct device instead of struct
class_device, so I don't have to convert the code later :)

> > On Fri, Sep 08, 2006 at 05:40:11PM -0400, Phillip Susi wrote:
> >> Greg KH wrote:
> >> >On Fri, Sep 08, 2006 at 07:55:08PM +0200, Thomas Maier wrote:
> >> >>+/sys/block/pktcdvd/<pktdevname>/packet/
> >> >>+    statistic         (r)  Show device statistic. One line with
> >> >>+                           5 values in following order:
> >> >>+                              packets-started
> >> >>+                              packets-end
> >> >>+                              written in kB
> >> >>+                              read gather in kB
> >> >>+                              read in kB
> >> >
> >> >Please no.  One value per file is the sysfs rule.
> >> >
> >>
> >> Except in cases like this where you want to read the status of the
> >> device at a given point in time, and you can't do that unless you grab
> >> all the values at once.
> >
> > Then don't use sysfs for that.  And is something like this as critical
> > to get that kind of information all in one atomic chunk?  It seems
> > merely to be informational.
> 
> The "statistic" and "info" files are only for information purpose.

Then please split them up into individual files.

> Into /proc ? No. (i read somewhere /proc should only contain process
> information in future)

Exactly.

> In debugfs? Hmm, this files should be infos that users should be able
> to read, no debug output.

Ok, then multiple files please.

> Is it ok, if i split the "statistic" into 5 files, and put the "info"
> into debugfs ?

Yes, that would be fine.

thanks,

greg k-h