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[14/16] nvme-rdma: Ensure dma support when using p2pdma

Message ID 20210408170123.8788-15-logang@deltatee.com (mailing list archive)
State New
Headers show
Series Add new DMA mapping operation for P2PDMA | expand

Commit Message

Logan Gunthorpe April 8, 2021, 5:01 p.m. UTC
Ensure the dma operations support p2pdma before using the RDMA
device for P2PDMA. This allows switching the RDMA driver from
pci_p2pdma_map_sg() to dma_map_sg_p2pdma().

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 drivers/nvme/target/rdma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Jason Gunthorpe April 27, 2021, 7:47 p.m. UTC | #1
On Thu, Apr 08, 2021 at 11:01:21AM -0600, Logan Gunthorpe wrote:
> Ensure the dma operations support p2pdma before using the RDMA
> device for P2PDMA. This allows switching the RDMA driver from
> pci_p2pdma_map_sg() to dma_map_sg_p2pdma().
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
>  drivers/nvme/target/rdma.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index 6c1f3ab7649c..3ec7e77e5416 100644
> +++ b/drivers/nvme/target/rdma.c
> @@ -414,7 +414,8 @@ static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
>  	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
>  		goto out_free_rsp;
>  
> -	if (!ib_uses_virt_dma(ndev->device))
> +	if (!ib_uses_virt_dma(ndev->device) &&
> +	    dma_pci_p2pdma_supported(&ndev->device->dev))

ib_uses_virt_dma() should not be called by nvme and this is using the
wrong device pointer to query for DMA related properties.

I suspect this wants a ib_dma_pci_p2p_dma_supported() wrapper like
everything else.

Jason
Logan Gunthorpe April 27, 2021, 10:59 p.m. UTC | #2
On 2021-04-27 1:47 p.m., Jason Gunthorpe wrote:
> On Thu, Apr 08, 2021 at 11:01:21AM -0600, Logan Gunthorpe wrote:
>> Ensure the dma operations support p2pdma before using the RDMA
>> device for P2PDMA. This allows switching the RDMA driver from
>> pci_p2pdma_map_sg() to dma_map_sg_p2pdma().
>>
>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
>>  drivers/nvme/target/rdma.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
>> index 6c1f3ab7649c..3ec7e77e5416 100644
>> +++ b/drivers/nvme/target/rdma.c
>> @@ -414,7 +414,8 @@ static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
>>  	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
>>  		goto out_free_rsp;
>>  
>> -	if (!ib_uses_virt_dma(ndev->device))
>> +	if (!ib_uses_virt_dma(ndev->device) &&
>> +	    dma_pci_p2pdma_supported(&ndev->device->dev))
> 
> ib_uses_virt_dma() should not be called by nvme and this is using the
> wrong device pointer to query for DMA related properties.
> 
> I suspect this wants a ib_dma_pci_p2p_dma_supported() wrapper like
> everything else.

Makes sense. Will add for v2.

Logan
John Hubbard May 3, 2021, 1:37 a.m. UTC | #3
On 4/8/21 10:01 AM, Logan Gunthorpe wrote:
> Ensure the dma operations support p2pdma before using the RDMA
> device for P2PDMA. This allows switching the RDMA driver from
> pci_p2pdma_map_sg() to dma_map_sg_p2pdma().

Tentatively, this looks right, but it really should be combined
with a following patch that uses it. Then you don't have to try
to explain, above, why it's needed. :)

> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> ---
>   drivers/nvme/target/rdma.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index 6c1f3ab7649c..3ec7e77e5416 100644
> --- a/drivers/nvme/target/rdma.c
> +++ b/drivers/nvme/target/rdma.c
> @@ -414,7 +414,8 @@ static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
>   	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
>   		goto out_free_rsp;
>   
> -	if (!ib_uses_virt_dma(ndev->device))
> +	if (!ib_uses_virt_dma(ndev->device) &&
> +	    dma_pci_p2pdma_supported(&ndev->device->dev))
>   		r->req.p2p_client = &ndev->device->dev;
>   	r->send_sge.length = sizeof(*r->req.cqe);
>   	r->send_sge.lkey = ndev->pd->local_dma_lkey;
> 

thanks,
diff mbox series

Patch

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 6c1f3ab7649c..3ec7e77e5416 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -414,7 +414,8 @@  static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
 	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
 		goto out_free_rsp;
 
-	if (!ib_uses_virt_dma(ndev->device))
+	if (!ib_uses_virt_dma(ndev->device) &&
+	    dma_pci_p2pdma_supported(&ndev->device->dev))
 		r->req.p2p_client = &ndev->device->dev;
 	r->send_sge.length = sizeof(*r->req.cqe);
 	r->send_sge.lkey = ndev->pd->local_dma_lkey;