Re: [PATCH v14 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing

[Claire Chang <tientzu@xxxxxxxxxxxx>]

On Thu, Jun 24, 2021 at 11:56 PM Konrad Rzeszutek Wilk
<konrad.wilk@xxxxxxxxxx> wrote:
>
> On Thu, Jun 24, 2021 at 10:10:51AM -0400, Qian Cai wrote:
> >
> >
> > On 6/24/2021 7:48 AM, Will Deacon wrote:
> > > Ok, diff below which attempts to tackle the offset issue I mentioned as
> > > well. Qian Cai -- please can you try with these changes?
> >
> > This works fine.
>
> Cool. Let me squash this patch in #6 and rebase the rest of them.
>
> Claire, could you check the devel/for-linus-5.14 say by end of today to
> double check that I didn't mess anything up please?

I just submitted v15 here
(https://lore.kernel.org/patchwork/cover/1451322/) in case it's
helpful.
I'll double check of course. Thanks for the efforts!

>
> Will,
>
> Thank you for generating the fix! I am going to run it on x86 and Xen
> to make sure all is good (granted last time I ran devel/for-linus-5.14
> on that setup I didn't see any errors so I need to double check
> I didn't do something silly like run a wrong kernel).
>
>
> >
> > >
> > > Will
> > >
> > > --->8
> > >
> > > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> > > index 175b6c113ed8..39284ff2a6cd 100644
> > > --- a/include/linux/swiotlb.h
> > > +++ b/include/linux/swiotlb.h
> > > @@ -116,7 +116,9 @@ static inline bool is_swiotlb_buffer(struct device 
> > > *dev, phys_addr_t paddr)
> > >
> > >  static inline bool is_swiotlb_force_bounce(struct device *dev)
> > >  {
> > > -       return dev->dma_io_tlb_mem->force_bounce;
> > > +       struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
> > > +
> > > +       return mem && mem->force_bounce;
> > >  }
> > >
> > >  void __init swiotlb_exit(void);
> > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> > > index 44be8258e27b..0ffbaae9fba2 100644
> > > --- a/kernel/dma/swiotlb.c
> > > +++ b/kernel/dma/swiotlb.c
> > > @@ -449,6 +449,7 @@ static int swiotlb_find_slots(struct device *dev, 
> > > phys_addr_t orig_addr,
> > >                 dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1);
> > >         unsigned int nslots = nr_slots(alloc_size), stride;
> > >         unsigned int index, wrap, count = 0, i;
> > > +       unsigned int offset = swiotlb_align_offset(dev, orig_addr);
> > >         unsigned long flags;
> > >
> > >         BUG_ON(!nslots);
> > > @@ -497,7 +498,7 @@ static int swiotlb_find_slots(struct device *dev, 
> > > phys_addr_t orig_addr,
> > >         for (i = index; i < index + nslots; i++) {
> > >                 mem->slots[i].list = 0;
> > >                 mem->slots[i].alloc_size =
> > > -                       alloc_size - ((i - index) << IO_TLB_SHIFT);
> > > +                       alloc_size - (offset + ((i - index) << 
> > > IO_TLB_SHIFT));
> > >         }
> > >         for (i = index - 1;
> > >              io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
> > >