Re: [RFC] generic device DMA implementation

James Bottomley (James.Bottomley@SteelEye.com)
Fri, 06 Dec 2002 16:48:57 -0600


davem@redhat.com said:
> It's like adding a new system call, and the same arguments apply.

> I don't want a 'flags' thing, because that tends to be the action
> which opens the flood gates for putting random feature-of-the-day new
> bits.

I did think of this. The flags are enums in include/linux/dma-mapping.h In
theory they can't be hijacked by an architecture without either changing this
global header or exciting compiler warnings.

However, I can only see their being two types of drivers: those which do all
the sync points and those which don't do any, so I can't see any reason for
there to be any more than two such flags.

I also want an active discouragement from using the may return inconsistent
API, and I think, given the general programmer predisposition not to want to
type, that a long flag name (or a long routine name) does this.

I just don't like API names that look like

dma_alloc_may_be_inconsistent()

but if that's what it takes, I'll do it

James

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