* [PATCH] PCI/P2PDMA: fix the wrong dma address calculation when map sg
@ 2021-09-09 3:25 Wang Lu
2021-09-09 16:51 ` Logan Gunthorpe
2021-09-09 17:28 ` Bjorn Helgaas
0 siblings, 2 replies; 3+ messages in thread
From: Wang Lu @ 2021-09-09 3:25 UTC (permalink / raw)
To: bhelgaas; +Cc: linux-pci, linux-kernel, Wang Lu
The bus offset is bus address - physical address,
so the calculation in __pci_p2pdma_map_sg should be:
bus address = physical address + bus offset.
Signed-off-by: Wang Lu <wanglu@dapustor.com>
---
drivers/pci/p2pdma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 50cdde3e9a8b..327882638b30 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -874,7 +874,7 @@ static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
int i;
for_each_sg(sg, s, nents, i) {
- s->dma_address = sg_phys(s) - p2p_pgmap->bus_offset;
+ s->dma_address = sg_phys(s) + p2p_pgmap->bus_offset;
sg_dma_len(s) = s->length;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] PCI/P2PDMA: fix the wrong dma address calculation when map sg
2021-09-09 3:25 [PATCH] PCI/P2PDMA: fix the wrong dma address calculation when map sg Wang Lu
@ 2021-09-09 16:51 ` Logan Gunthorpe
2021-09-09 17:28 ` Bjorn Helgaas
1 sibling, 0 replies; 3+ messages in thread
From: Logan Gunthorpe @ 2021-09-09 16:51 UTC (permalink / raw)
To: Wang Lu, bhelgaas; +Cc: linux-pci, linux-kernel
On 2021-09-08 9:25 p.m., Wang Lu wrote:
> The bus offset is bus address - physical address,
> so the calculation in __pci_p2pdma_map_sg should be:
> bus address = physical address + bus offset.
>
> Signed-off-by: Wang Lu <wanglu@dapustor.com>
Thanks, yes I believe my math was wrong here.
It was never tested on any machine that has a non-zero bus-offset.
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] PCI/P2PDMA: fix the wrong dma address calculation when map sg
2021-09-09 3:25 [PATCH] PCI/P2PDMA: fix the wrong dma address calculation when map sg Wang Lu
2021-09-09 16:51 ` Logan Gunthorpe
@ 2021-09-09 17:28 ` Bjorn Helgaas
1 sibling, 0 replies; 3+ messages in thread
From: Bjorn Helgaas @ 2021-09-09 17:28 UTC (permalink / raw)
To: Wang Lu; +Cc: bhelgaas, linux-pci, linux-kernel, Logan Gunthorpe
On Thu, Sep 09, 2021 at 11:25:28AM +0800, Wang Lu wrote:
> The bus offset is bus address - physical address,
> so the calculation in __pci_p2pdma_map_sg should be:
> bus address = physical address + bus offset.
>
> Signed-off-by: Wang Lu <wanglu@dapustor.com>
Applied with Logan's reviewed-by to pci/p2pdma for v5.16, thanks!
I fixed the subject line and commit log for you to follow the usual
conventions.
> ---
> drivers/pci/p2pdma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> index 50cdde3e9a8b..327882638b30 100644
> --- a/drivers/pci/p2pdma.c
> +++ b/drivers/pci/p2pdma.c
> @@ -874,7 +874,7 @@ static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
> int i;
>
> for_each_sg(sg, s, nents, i) {
> - s->dma_address = sg_phys(s) - p2p_pgmap->bus_offset;
> + s->dma_address = sg_phys(s) + p2p_pgmap->bus_offset;
> sg_dma_len(s) = s->length;
> }
>
> --
> 2.17.1
>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-09-09 17:28 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-09-09 3:25 [PATCH] PCI/P2PDMA: fix the wrong dma address calculation when map sg Wang Lu
2021-09-09 16:51 ` Logan Gunthorpe
2021-09-09 17:28 ` Bjorn Helgaas
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