2019-08-05 15:53:38

by Lucas Stach

Subject: [PATCH] dma-direct: don't truncate dma_required_mask to bus addressing capabilities

The dma required_mask needs to reflect the actual addressing capabilities
needed to handle the whole system RAM. When truncated down to the bus
addressing capabilities dma_addressing_limited() will incorrectly signal
no limitations for devices which are restricted by the bus_dma_mask.

Fixes: b4ebe6063204 (dma-direct: implement complete bus_dma_mask handling)
Signed-off-by: Lucas Stach <[email protected]>
---
kernel/dma/direct.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 59bdceea3737..7ba3480fc546 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -47,9 +47,6 @@ u64 dma_direct_get_required_mask(struct device *dev)
{
u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT);

- if (dev->bus_dma_mask && dev->bus_dma_mask < max_dma)
- max_dma = dev->bus_dma_mask;
-
return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
}

--
2.20.1

2019-08-06 05:24:21

by Christoph Hellwig

Subject: Re: [PATCH] dma-direct: don't truncate dma_required_mask to bus addressing capabilities

On Mon, Aug 05, 2019 at 05:51:53PM +0200, Lucas Stach wrote:
> The dma required_mask needs to reflect the actual addressing capabilities
> needed to handle the whole system RAM. When truncated down to the bus
> addressing capabilities dma_addressing_limited() will incorrectly signal
> no limitations for devices which are restricted by the bus_dma_mask.
>
> Fixes: b4ebe6063204 (dma-direct: implement complete bus_dma_mask handling)
> Signed-off-by: Lucas Stach <[email protected]>

Yeah, this looks sensible. Atish, can you check if this helps on the
HiFive board as well?

2019-08-06 20:19:12

by Atish Patra

Subject: Re: [PATCH] dma-direct: don't truncate dma_required_mask to bus addressing capabilities

On Tue, 2019-08-06 at 07:23 +0200, Christoph Hellwig wrote:
> On Mon, Aug 05, 2019 at 05:51:53PM +0200, Lucas Stach wrote:
> > The dma required_mask needs to reflect the actual addressing
> > capabilities
> > needed to handle the whole system RAM. When truncated down to the
> > bus
> > addressing capabilities dma_addressing_limited() will incorrectly
> > signal
> > no limitations for devices which are restricted by the
> > bus_dma_mask.
> >
> > Fixes: b4ebe6063204 (dma-direct: implement complete bus_dma_mask
> > handling)
> > Signed-off-by: Lucas Stach <[email protected]>
>
> Yeah, this looks sensible. Atish, can you check if this helps on the
> HiFive board as well?

Yes. It fixes the nvme issue on HiFive Unleashed + Microsemi expansion
board.

FWIW,

Tested-by: Atish Patra <[email protected]>


Regards,
Atish