Re: [Qemu-devel] [PATCH] honor IDE_DMA_BUF_SECTORS

[Samuel Thibault]

Avi Kivity, le Fri 27 Mar 2009 12:52:15 +0300, a écrit :
> However implementing DMA limits like you propose 
> (IDE_DMA_BUF_SECTORS) will not fix the bug, only reduce performance.

Have you read what I wrote? v

> >Just to make sure: I'm _not_ saying that should be done in the DMA
> >code.  I said it should be done in the block layer, shared by all
> >block drivers.
> 
> A generic fix will have to issue a new aio request.

Ah, right, that's different from the case below.

> block-raw-posix need not do that, just a while loop.

For the synchronous interface, yes. For the asynchronous interface,
short reads could happen too... (unfortunately we are aware of that too
late for queuing other requests and getting efficiency).

Samuel