Re: [ckrm-tech] [PATCH 0/5] Allow more than PAGESIZE data read in configfs

[Joel Becker]

On Tue, Oct 10, 2006 at 05:49:59PM -0700, Matt Helsley wrote:
> 	We want to be able to export a sequence of small (<< 1 page),
> homogenous, unstructured (scalar), attributes through configfs using the
> same file. While this is rather specific, I'd guess it would be a common
> occurrence.

	Pray tell, why?  "One attribute per file" is the mantra here.
You really should think hard before you break it.  Simple heuristic:
would you have to parse the buffer?  Then it's wrong.

> 	Yes, keeping track of writing to these sequences (add, remove, replace)
> is a problem. But that's what the file position is for. configfs could
> 
> 	Does this seem reasonable?

	No.  It adds complexity to an interface that is supposed to be
simple.  Now, I'm not sure what you are trying to do here, so I don't
know how it fits in.  Is it really "multiple attributes per file", or
"this attribute is a list of entries"?
	An example.  If you had to set an IP address and a port, here's
your scenarios:

[Right]
    echo "10.0.0.1" > /sys/kernel/config/subsys/item/address
    echo "8000" > /sys/kernel/config/subsys/item/port

[Wrong]
    echo 10.0.0.1\n8000" > /sys/kernel/config/subsys/item/address-and-port

	But perhaps you are not setting two distinct attributes.  I
don't understand what you are doing, so some detail would be nice.

Joel

-- 

Life's Little Instruction Book #407

	"Every once in a while, take the scenic route."

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@xxxxxxxxxx
Phone: (650) 506-8127
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