RE: dma engine drivers for 2.6.25?

From: Zhang Wei
Date: Mon Feb 25 2008 - 06:05:44 EST


Hi,

Sorry for missing lots of emails in my long vacation. :)

> -----Original Message-----
> From: dan.j.williams@xxxxxxxxx
> [mailto:dan.j.williams@xxxxxxxxx] On Behalf Of Dan Williams
> Sent: Sunday, February 24, 2008 10:06 AM
> To: Kumar Gala
> Cc: LKML Kernel; Zhang Wei
> Subject: Re: dma engine drivers for 2.6.25?
>
> On Thu, Feb 14, 2008 at 10:29 PM, Dan Williams
> <dan.j.williams@xxxxxxxxx> wrote:
> > On Thu, Feb 14, 2008 at 8:44 PM, Kumar Gala
> <galak@xxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > On Feb 14, 2008, at 12:14 PM, Dan Williams wrote:
> > >
> > > > On Wed, Feb 13, 2008 at 8:52 PM, Kumar Gala
> > > > <galak@xxxxxxxxxxxxxxxxxxx> wrote:
> > > >> Dan,
> > > >>
> > > >> What's going on with the dma engine drivers for
> 2.6.25? We had a
> > > >> Freescale dma driver from Zhang Wei queued up but
> seems to have been
> > > >> lost.
> > > >
> > > > I pulled it into my tree and am holding it until Zhang has an
> > > > opportunity to address the pending review comments
> [1]. I also did
> > > > not feel comfortable pushing it to Linus without a
> PPC maintainer's
> > > > Acked-by/Reviewed-by.
> > > >
> > > > I have attached the version I am carrying.
> > >
> > > What issues are still open. I was under the belief
> that Zhang had
> > > resolved all the issues.
> > >
> >
> > The high priority review item is that the driver performs operation
> > completion callbacks in hardirq context. Clients of the API assume
> > that callbacks will happen in softirq context. Of lesser
> concern is
> > the use of GFP_ATOMIC in fsl_dma_alloc_descriptor. Other drivers
> > preallocate a small pool of descriptors.
> >
>
> Have not received a response, so let's try this the other way. I took
> a closer look and found that my concern should be addressed by the
> following one-liner:
>
> diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
> index 902e852..cc9a681 100644
> --- a/drivers/dma/fsldma.c
> +++ b/drivers/dma/fsldma.c
> @@ -685,7 +685,6 @@ static irqreturn_t fsl_dma_chan_do_interrupt(int
> irq, void *data)
> "nlndar 0x%016llx\n",
> (u64)get_cdar(fsl_chan),
> (u64)get_ndar(fsl_chan));
> stat &= ~FSL_DMA_SR_EOSI;
> - fsl_chan_ld_cleanup(fsl_chan);
> }
>
> /* If it current transfer is the end-of-transfer,
>
> With your ack I'll push the driver plus this fixlet for the
> current kernel.

I agree with you to remove the fsl_chan_ld_cleanup() function calling in
Interrupt action, which is already called in tasklet. I forgot to remove it.
Thanks!

Cheers!
Wei.

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