Re: [PATCH] [0/6] kfifo fixes/improvements

From: Dmitry Torokhov
Date: Tue Dec 29 2009 - 17:28:41 EST


On Dec 29, 2009, at 12:40 AM, Stefani Seibold <stefani@xxxxxxxxxxx> wrote:

Am Montag, den 28.12.2009, 21:40 +0100 schrieb Andi Kleen:


OK i checked and they all use power-of-two currently so by sheer
luck (I doubt it is by design) they work. Still I think that
open deathtrap should be fixed.


It is fixed, and i hope it will be included in 2.6.34.

I also don't understand how that patch "breaks your future work"
Please elaborate on that.


Very difficult to explain in a email, but i will try it:

The new macro based kfifo API handles everything as elements of a given
type. So you can have the old "unsigned char"-fifo, but also fifo of
every other type like int's, struct's and so on. The kfifo_in() and
kfifo_out() len parameter is than in the meaning of elements not bytes.
So you are able to process more than one value at a time and the macros
will return the number of processed elements (not bytes).

Does anyone want this kind of functionality though? Why can't we keep the old interface as is (and maybe deprecate it) and use the new record API you mentioned below for record-oriented kfifos.

Thanks.

--
Dmitry

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