diff mbox series

[13/16] nvme-pci: Convert to using dma_map_sg_p2pdma for p2pdma pages

Message ID 20210408170123.8788-14-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
Convert to using dma_map_sg_p2pdma() for PCI p2pdma pages.

This should be equivalent but allows for heterogeneous scatterlists
with both P2PDMA and regular pages. However, P2PDMA support will be
slightly more restricted (only dma-direct and dma-iommu are currently
supported).

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 drivers/nvme/host/pci.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

Comments

John Hubbard May 3, 2021, 1:34 a.m. UTC | #1
On 4/8/21 10:01 AM, Logan Gunthorpe wrote:
> Convert to using dma_map_sg_p2pdma() for PCI p2pdma pages.
> 
> This should be equivalent but allows for heterogeneous scatterlists
> with both P2PDMA and regular pages. However, P2PDMA support will be
> slightly more restricted (only dma-direct and dma-iommu are currently
> supported).
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> ---
>   drivers/nvme/host/pci.c | 28 ++++++++--------------------
>   1 file changed, 8 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 14f092973792..a1ed07ff38b7 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -577,17 +577,6 @@ static void nvme_free_sgls(struct nvme_dev *dev, struct request *req)
>   
>   }
>   
> -static void nvme_unmap_sg(struct nvme_dev *dev, struct request *req)
> -{
> -	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
> -
> -	if (is_pci_p2pdma_page(sg_page(iod->sg)))
> -		pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents,
> -				    rq_dma_dir(req));
> -	else
> -		dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
> -}
> -
>   static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
>   {
>   	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
> @@ -600,7 +589,7 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
>   
>   	WARN_ON_ONCE(!iod->nents);
>   
> -	nvme_unmap_sg(dev, req);
> +	dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));


Nice simplification!


>   	if (iod->npages == 0)
>   		dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0],
>   			      iod->first_dma);
> @@ -868,14 +857,13 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
>   	if (!iod->nents)
>   		goto out_free_sg;
>   
> -	if (is_pci_p2pdma_page(sg_page(iod->sg)))
> -		nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg,
> -				iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN);
> -	else
> -		nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
> -					     rq_dma_dir(req), DMA_ATTR_NO_WARN);
> -	if (!nr_mapped)
> +	nr_mapped = dma_map_sg_p2pdma_attrs(dev->dev, iod->sg, iod->nents,
> +				     rq_dma_dir(req), DMA_ATTR_NO_WARN);
> +	if (nr_mapped < 0) {
> +		if (nr_mapped != -ENOMEM)
> +			ret = BLK_STS_TARGET;
>   		goto out_free_sg;
> +	}

But now the "nr_mapped == 0" case is no longer doing an early out_free_sg.
Is that OK?

>   
>   	iod->use_sgl = nvme_pci_use_sgls(dev, req);
>   	if (iod->use_sgl)
> @@ -887,7 +875,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
>   	return BLK_STS_OK;
>   
>   out_unmap_sg:
> -	nvme_unmap_sg(dev, req);
> +	dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
>   out_free_sg:
>   	mempool_free(iod->sg, dev->iod_mempool);
>   	return ret;
> 

thanks,
Logan Gunthorpe May 3, 2021, 5:19 p.m. UTC | #2
On 2021-05-02 7:34 p.m., John Hubbard wrote:
>>   	if (iod->npages == 0)
>>   		dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0],
>>   			      iod->first_dma);
>> @@ -868,14 +857,13 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
>>   	if (!iod->nents)
>>   		goto out_free_sg;
>>   
>> -	if (is_pci_p2pdma_page(sg_page(iod->sg)))
>> -		nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg,
>> -				iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN);
>> -	else
>> -		nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
>> -					     rq_dma_dir(req), DMA_ATTR_NO_WARN);
>> -	if (!nr_mapped)
>> +	nr_mapped = dma_map_sg_p2pdma_attrs(dev->dev, iod->sg, iod->nents,
>> +				     rq_dma_dir(req), DMA_ATTR_NO_WARN);
>> +	if (nr_mapped < 0) {
>> +		if (nr_mapped != -ENOMEM)
>> +			ret = BLK_STS_TARGET;
>>   		goto out_free_sg;
>> +	}
> 
> But now the "nr_mapped == 0" case is no longer doing an early out_free_sg.
> Is that OK?

dma_map_sg_p2pdma_attrs() never returns zero. It will return -ENOMEM in
the same situation and results in the same goto out_free_sg.

Logan
John Hubbard May 4, 2021, 12:26 a.m. UTC | #3
On 5/3/21 10:19 AM, Logan Gunthorpe wrote:
...
>>> +	nr_mapped = dma_map_sg_p2pdma_attrs(dev->dev, iod->sg, iod->nents,
>>> +				     rq_dma_dir(req), DMA_ATTR_NO_WARN);
>>> +	if (nr_mapped < 0) {
>>> +		if (nr_mapped != -ENOMEM)
>>> +			ret = BLK_STS_TARGET;
>>>    		goto out_free_sg;
>>> +	}
>>
>> But now the "nr_mapped == 0" case is no longer doing an early out_free_sg.
>> Is that OK?
> 
> dma_map_sg_p2pdma_attrs() never returns zero. It will return -ENOMEM in
> the same situation and results in the same goto out_free_sg.
> 

OK...that's true, it doesn't return zero. A comment or WARN or something
might be nice, to show that the zero case hasn't been overlooked. It's
true that the dma_map_sg_p2pdma_attrs() documentation sort of says
that (although not quite out loud).

thanks,
diff mbox series

Patch

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 14f092973792..a1ed07ff38b7 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -577,17 +577,6 @@  static void nvme_free_sgls(struct nvme_dev *dev, struct request *req)
 
 }
 
-static void nvme_unmap_sg(struct nvme_dev *dev, struct request *req)
-{
-	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-
-	if (is_pci_p2pdma_page(sg_page(iod->sg)))
-		pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents,
-				    rq_dma_dir(req));
-	else
-		dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
-}
-
 static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
@@ -600,7 +589,7 @@  static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
 
 	WARN_ON_ONCE(!iod->nents);
 
-	nvme_unmap_sg(dev, req);
+	dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
 	if (iod->npages == 0)
 		dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0],
 			      iod->first_dma);
@@ -868,14 +857,13 @@  static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 	if (!iod->nents)
 		goto out_free_sg;
 
-	if (is_pci_p2pdma_page(sg_page(iod->sg)))
-		nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg,
-				iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN);
-	else
-		nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
-					     rq_dma_dir(req), DMA_ATTR_NO_WARN);
-	if (!nr_mapped)
+	nr_mapped = dma_map_sg_p2pdma_attrs(dev->dev, iod->sg, iod->nents,
+				     rq_dma_dir(req), DMA_ATTR_NO_WARN);
+	if (nr_mapped < 0) {
+		if (nr_mapped != -ENOMEM)
+			ret = BLK_STS_TARGET;
 		goto out_free_sg;
+	}
 
 	iod->use_sgl = nvme_pci_use_sgls(dev, req);
 	if (iod->use_sgl)
@@ -887,7 +875,7 @@  static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 	return BLK_STS_OK;
 
 out_unmap_sg:
-	nvme_unmap_sg(dev, req);
+	dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
 out_free_sg:
 	mempool_free(iod->sg, dev->iod_mempool);
 	return ret;