[PATCH] swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit

[PATCH] swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit

[Christoph Hellwig]

Otherwise is_swiotlb_buffer will return false positives when
we first initialize a swiotlb buffer, but then free it because
we have an IOMMU available.

Fixes: 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
Reported-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>
Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
Tested-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>
---
 kernel/dma/swiotlb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index d6361776dc5c..1fb6fd68b9c7 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -378,6 +378,8 @@ void __init swiotlb_exit(void)
 		memblock_free_late(io_tlb_start,
 				   PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
 	}
+	io_tlb_start = 0;
+	io_tlb_end = 0;
 	io_tlb_nslabs = 0;
 	max_segment = 0;
 }
-- 
2.20.1

Re: [PATCH] swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit

[Konrad Rzeszutek Wilk]

On Mon, Jan 14, 2019 at 09:14:08PM +0100, Christoph Hellwig wrote:
> Otherwise is_swiotlb_buffer will return false positives when
> we first initialize a swiotlb buffer, but then free it because
> we have an IOMMU available.
> 
> Fixes: 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
> Reported-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>
> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> Tested-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

Thank you!
> ---
>  kernel/dma/swiotlb.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index d6361776dc5c..1fb6fd68b9c7 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -378,6 +378,8 @@ void __init swiotlb_exit(void)
>  		memblock_free_late(io_tlb_start,
>  				   PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
>  	}
> +	io_tlb_start = 0;
> +	io_tlb_end = 0;
>  	io_tlb_nslabs = 0;
>  	max_segment = 0;
>  }
> -- 
> 2.20.1
> 

Re: [PATCH] swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit

[Christoph Hellwig]

On Mon, Jan 14, 2019 at 03:25:13PM -0500, Konrad Rzeszutek Wilk wrote:
> On Mon, Jan 14, 2019 at 09:14:08PM +0100, Christoph Hellwig wrote:
> > Otherwise is_swiotlb_buffer will return false positives when
> > we first initialize a swiotlb buffer, but then free it because
> > we have an IOMMU available.
> > 
> > Fixes: 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
> > Reported-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>
> > Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> > Tested-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>
> 
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

Do you want to send this to Linus, or do you want me to pick it up
through the dma-mapping tree?

Re: [PATCH] swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit

[Konrad Rzeszutek Wilk]

On Mon, Jan 14, 2019 at 09:33:23PM +0100, Christoph Hellwig wrote:
> On Mon, Jan 14, 2019 at 03:25:13PM -0500, Konrad Rzeszutek Wilk wrote:
> > On Mon, Jan 14, 2019 at 09:14:08PM +0100, Christoph Hellwig wrote:
> > > Otherwise is_swiotlb_buffer will return false positives when
> > > we first initialize a swiotlb buffer, but then free it because
> > > we have an IOMMU available.
> > > 
> > > Fixes: 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
> > > Reported-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>
> > > Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> > > Tested-by: Sibren Vasse <sibren-DLwv2wemLo05ZU0pBKPMFg@public.gmane.org>
> > 
> > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> 
> Do you want to send this to Linus, or do you want me to pick it up
> through the dma-mapping tree?

I will do it. Thanks!