Re: I request inclusion of SAS Transport Layer and AIC-94xx into the kernel

[Joel Becker]

On Fri, Sep 30, 2005 at 03:15:50PM -0600, Andrew Patterson wrote:
> But again, this may be just a goal and not a hard and fast rule.  I can
> definitely see a use for binary attributes in sysfs. Configfs seems to
> be designed for this sort of thing.

	Configfs is designed for ascii or readable attributes.  It drops
the bin_attribute type that sysfs still supports.  So if you are looking
to fill a 64K binary attribute, configfs isn't the place you're going to
be going.

> > fd = open(smp_portal, ...);
> > write(fd, smp_req, smp_req_size);
> > read(fd, smp_resp, smp_resp_size);
> > close(fd);
> 
> Process A opens an attribute and writes to it.  Process B opens another
> attribute and writes to it, affecting the result that process A will see
> from its subsequent read. I suppose you could lock every attribute, but
> that would be very error-prone, and not allow much concurrency.

	Check out nfsctl.c and its transaction_file design.  process A
and process B get different buffers on filp->f_private, and cannot
influence each other's read/write operations.

Joel

-- 

Life's Little Instruction Book #347

	"Never waste the oppourtunity to tell someone you love them."

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