(cc'ing Li)

Hello, Andrew.

On Tue, Jun 26, 2012 at 03:25:22PM -0700, Andrew Morton wrote:

hm.  The various .write_u64() implementations go and return zero on
success and cgroup_write_X64() sees this and rewrites the return value
to `nbytes'.

That was a bit naughty of us - it prevents a .write_u64() instance from
being able to fully implement a partial write.  We can *partially*
implement a partial write, by returning a value between 1 and nbytes-1,
but we can't return zero.  It's a weird interface, it's a surprising
interface and it was quite unnecessary to do it this way.  Someone
please slap Paul.

It's hardly a big problem I, but that's why the unix write() interface
was designed the way it is.

The whole file interface is severely over-designed like a lot of other
things in cgorup.  I'm thinking about consolidating all the different
read/write methods into one generic pair, likely based on seq_file and
make all others helpers.

Thanks.

-- 
tejun

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