Re: [PATCH 4.14 064/109] dmaengine: bcm2835-dma: Use vchan_terminate_vdesc() instead of desc_free

[Vinod Koul]

On Fri, Mar 16, 2018 at 01:46:40PM -0500, Dan Rue wrote:
> On Fri, Mar 16, 2018 at 04:23:33PM +0100, Greg Kroah-Hartman wrote:
> > 4.14-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> > 
> > 
> > [ Upstream commit de92436ac40ffe9933230aa503e24dbb5ede9201 ]
> > 
> > To avoid race with vchan_complete, use the race free way to terminate
> > running transfer.
> > 
> > Implement the device_synchronize callback to make sure that the terminated
> > descriptor is freed.
> > 
> > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> > Acked-by: Eric Anholt <eric@xxxxxxxxxx>
> > Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> This patch is causing a build error on arm and arm64 per i.e.
> https://kernelci.org/build/id/5aac017e59b5141cb1b3a4d5/
> 
> Builds are also failing for arm/arm64 on 4.15 and this patch seems to be a
> problem there as well, but I have not verified it yet.

I think we are missing commit 1c7f072d94e8. Pls cherrypick that as well

commit 1c7f072d94e8b697fd9b70cdb268622a18faf522
Author: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
Date:   Tue Nov 14 16:32:04 2017 +0200

    dmaengine: virt-dma: Support for race free transfer termination

This adds vchan_terminate_vdesc API..


> 
> #
> # make -j10 -k -s ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- O=build-arm64 defconfig
> #
> #
> # make -j10 -k -s ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- O=build-arm64
> #
> arch/arm64/Makefile:48: Detected assembler with broken .inst; disassembly will be unreliable
> ../drivers/dma/bcm2835-dma.c: In function 'bcm2835_dma_terminate_all':
> ../drivers/dma/bcm2835-dma.c:815:3: error: implicit declaration of function 'vchan_terminate_vdesc' [-Werror=implicit-function-declaration]
>    vchan_terminate_vdesc(&c->desc->vd);
>    ^
> cc1: some warnings being treated as errors
> ../scripts/Makefile.build:334: recipe for target 'drivers/dma/bcm2835-dma.o' failed
> make[3]: *** [drivers/dma/bcm2835-dma.o] Error 1
> make[3]: Target '__build' not remade because of errors.
> ../scripts/Makefile.build:587: recipe for target 'drivers/dma' failed
> make[2]: *** [drivers/dma] Error 2
> make[2]: Target '__build' not remade because of errors.
> /home/buildslave/workspace/kernel-single-defconfig-builder/defconfig/defconfig/label/builder/Makefile:1031: recipe for target 'drivers' failed
> make[1]: *** [drivers] Error 2
> make[1]: Target '_all' not remade because of errors.
> Makefile:146: recipe for target 'sub-make' failed
> make: *** [sub-make] Error 2
> make: Target '_all' not remade because of errors.
> 
> > ---
> >  drivers/dma/bcm2835-dma.c |   10 +++++++++-
> >  1 file changed, 9 insertions(+), 1 deletion(-)
> > 
> > --- a/drivers/dma/bcm2835-dma.c
> > +++ b/drivers/dma/bcm2835-dma.c
> > @@ -812,7 +812,7 @@ static int bcm2835_dma_terminate_all(str
> >  	 * c->desc is NULL and exit.)
> >  	 */
> >  	if (c->desc) {
> > -		bcm2835_dma_desc_free(&c->desc->vd);
> > +		vchan_terminate_vdesc(&c->desc->vd);
> >  		c->desc = NULL;
> >  		bcm2835_dma_abort(c->chan_base);
> >  
> > @@ -836,6 +836,13 @@ static int bcm2835_dma_terminate_all(str
> >  	return 0;
> >  }
> >  
> > +static void bcm2835_dma_synchronize(struct dma_chan *chan)
> > +{
> > +	struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
> > +
> > +	vchan_synchronize(&c->vc);
> > +}
> > +
> >  static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,
> >  				 int irq, unsigned int irq_flags)
> >  {
> > @@ -942,6 +949,7 @@ static int bcm2835_dma_probe(struct plat
> >  	od->ddev.device_prep_dma_memcpy = bcm2835_dma_prep_dma_memcpy;
> >  	od->ddev.device_config = bcm2835_dma_slave_config;
> >  	od->ddev.device_terminate_all = bcm2835_dma_terminate_all;
> > +	od->ddev.device_synchronize = bcm2835_dma_synchronize;
> >  	od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
> >  	od->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
> >  	od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
> > 
> > 

-- 
~Vinod