RE: [PATCH v2 3/3] dma: Add Freescale eDMA engine driver support

From: Lu Jingchang-B35083
Date: Tue Aug 06 2013 - 01:16:13 EST




> -----Original Message-----
> From: Vinod Koul [mailto:vinod.koul@xxxxxxxxx]
> Sent: Tuesday, August 06, 2013 12:25 PM
> To: Lu Jingchang-B35083
> Cc: djbw@xxxxxx; shawn.guo@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Wang Huan-B18965; Li Xiaochun-
> B41219
> Subject: Re: [PATCH v2 3/3] dma: Add Freescale eDMA engine driver support
>
> On Tue, Aug 06, 2013 at 01:24:31AM +0000, Lu Jingchang-B35083 wrote:
> > > -----Original Message-----
> > > From: Vinod Koul [mailto:vinod.koul@xxxxxxxxx]
> > > Sent: Tuesday, August 06, 2013 12:35 AM
> > > To: Lu Jingchang-B35083
> > > Cc: djbw@xxxxxx; shawn.guo@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Wang Huan-B18965; Li Xiaochun-
> > > B41219
> > > Subject: Re: [PATCH v2 3/3] dma: Add Freescale eDMA engine driver
> > > support
> > > > +
> > > > +static void fsl_edma_free_desc(struct virt_dma_desc *vdesc) {
> > > > + struct fsl_edma_desc *fsl_desc;
> > > > + int i;
> > > > +
> > > > + fsl_desc = to_fsl_edma_desc(vdesc);
> > > > + for (i = 0; i < fsl_desc->n_tcds; i++)
> > > > + dma_pool_free(fsl_desc->echan->tcd_pool,
> > > > + fsl_desc->tcd[i].vtcd,
> > > > + fsl_desc->tcd[i].ptcd);
> > > > + kfree(fsl_desc);
> > > should this be called with lock held or not?
> > [Lu Jingchang-B35083]
> > The desc list to be freed is got with lock held, and the free for each
> desc is independent, and the lock is not needed. Thanks.
> Would be apt to add this comment in the code, so that people know this
> function needs to be always called with lock held!
[Lu Jingchang-B35083]
Sorry, this function is called without lock held, I mean that the free() doesn't need the lock held,
just as other drivers do.
It is called from vchan_free_chan_resources().
Thanks!


Best Regards,
Jingchang


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