diff mbox series

[v3,09/20] nvme-pci: check DMA ops when indicating support for PCI P2PDMA

Message ID 20210916234100.122368-10-logang@deltatee.com (mailing list archive)
State New, archived
Headers show
Series Userspace P2PDMA with O_DIRECT NVMe devices | expand

Commit Message

Logan Gunthorpe Sept. 16, 2021, 11:40 p.m. UTC
Introduce a supports_pci_p2pdma() operation in nvme_ctrl_ops to
replace the fixed NVME_F_PCI_P2PDMA flag such that the dma_map_ops
flags can be checked for PCI P2PDMA support.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 drivers/nvme/host/core.c |  3 ++-
 drivers/nvme/host/nvme.h |  2 +-
 drivers/nvme/host/pci.c  | 11 +++++++++--
 3 files changed, 12 insertions(+), 4 deletions(-)

Comments

Chaitanya Kulkarni Sept. 30, 2021, 5:06 a.m. UTC | #1
Logan,

> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 7efb31b87f37..916750a54f60 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -3771,7 +3771,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
>                  blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, ns->queue);
> 
>          blk_queue_flag_set(QUEUE_FLAG_NONROT, ns->queue);
> -       if (ctrl->ops->flags & NVME_F_PCI_P2PDMA)
> +       if (ctrl->ops->supports_pci_p2pdma &&
> +           ctrl->ops->supports_pci_p2pdma(ctrl))
>                  blk_queue_flag_set(QUEUE_FLAG_PCI_P2PDMA, ns->queue);
> 
>          ns->ctrl = ctrl;
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 9871c0c9374c..fb9bfc52a6d7 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -477,7 +477,6 @@ struct nvme_ctrl_ops {
>          unsigned int flags;
>   #define NVME_F_FABRICS                 (1 << 0)
>   #define NVME_F_METADATA_SUPPORTED      (1 << 1)
> -#define NVME_F_PCI_P2PDMA              (1 << 2)
>          int (*reg_read32)(struct nvme_ctrl *ctrl, u32 off, u32 *val);
>          int (*reg_write32)(struct nvme_ctrl *ctrl, u32 off, u32 val);
>          int (*reg_read64)(struct nvme_ctrl *ctrl, u32 off, u64 *val);
> @@ -485,6 +484,7 @@ struct nvme_ctrl_ops {
>          void (*submit_async_event)(struct nvme_ctrl *ctrl);
>          void (*delete_ctrl)(struct nvme_ctrl *ctrl);
>          int (*get_address)(struct nvme_ctrl *ctrl, char *buf, int size);
> +       bool (*supports_pci_p2pdma)(struct nvme_ctrl *ctrl);
>   };
> 

Is this new ops only needed for the PCIe transport ? or do you have 
following patches to use this op for the other transports ?

If it is only needed for the PCIe then we need to find a way to
not add this somehow...
Logan Gunthorpe Sept. 30, 2021, 4:51 p.m. UTC | #2
On 2021-09-29 11:06 p.m., Chaitanya Kulkarni wrote:
> Logan,
> 
>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>> index 7efb31b87f37..916750a54f60 100644
>> --- a/drivers/nvme/host/core.c
>> +++ b/drivers/nvme/host/core.c
>> @@ -3771,7 +3771,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
>>                  blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, ns->queue);
>>
>>          blk_queue_flag_set(QUEUE_FLAG_NONROT, ns->queue);
>> -       if (ctrl->ops->flags & NVME_F_PCI_P2PDMA)
>> +       if (ctrl->ops->supports_pci_p2pdma &&
>> +           ctrl->ops->supports_pci_p2pdma(ctrl))
>>                  blk_queue_flag_set(QUEUE_FLAG_PCI_P2PDMA, ns->queue);
>>
>>          ns->ctrl = ctrl;
>> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
>> index 9871c0c9374c..fb9bfc52a6d7 100644
>> --- a/drivers/nvme/host/nvme.h
>> +++ b/drivers/nvme/host/nvme.h
>> @@ -477,7 +477,6 @@ struct nvme_ctrl_ops {
>>          unsigned int flags;
>>   #define NVME_F_FABRICS                 (1 << 0)
>>   #define NVME_F_METADATA_SUPPORTED      (1 << 1)
>> -#define NVME_F_PCI_P2PDMA              (1 << 2)
>>          int (*reg_read32)(struct nvme_ctrl *ctrl, u32 off, u32 *val);
>>          int (*reg_write32)(struct nvme_ctrl *ctrl, u32 off, u32 val);
>>          int (*reg_read64)(struct nvme_ctrl *ctrl, u32 off, u64 *val);
>> @@ -485,6 +484,7 @@ struct nvme_ctrl_ops {
>>          void (*submit_async_event)(struct nvme_ctrl *ctrl);
>>          void (*delete_ctrl)(struct nvme_ctrl *ctrl);
>>          int (*get_address)(struct nvme_ctrl *ctrl, char *buf, int size);
>> +       bool (*supports_pci_p2pdma)(struct nvme_ctrl *ctrl);
>>   };
>>
> 
> Is this new ops only needed for the PCIe transport ? or do you have 
> following patches to use this op for the other transports ?

No, I don't think this will make sense for transports that are not based
on PCI devices.

> If it is only needed for the PCIe then we need to find a way to
> not add this somehow...

I don't see how we can do that. The core code needs to know whether the
transport supports this and must have an operation to query it.

Logan
Chaitanya Kulkarni Sept. 30, 2021, 5:19 p.m. UTC | #3
>>
>> Is this new ops only needed for the PCIe transport ? or do you have
>> following patches to use this op for the other transports ?
> 
> No, I don't think this will make sense for transports that are not based
> on PCI devices.
> 
>> If it is only needed for the PCIe then we need to find a way to
>> not add this somehow...
> 
> I don't see how we can do that. The core code needs to know whether the
> transport supports this and must have an operation to query it.
> 

Okay.

> Logan
>
diff mbox series

Patch

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7efb31b87f37..916750a54f60 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3771,7 +3771,8 @@  static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 		blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, ns->queue);
 
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, ns->queue);
-	if (ctrl->ops->flags & NVME_F_PCI_P2PDMA)
+	if (ctrl->ops->supports_pci_p2pdma &&
+	    ctrl->ops->supports_pci_p2pdma(ctrl))
 		blk_queue_flag_set(QUEUE_FLAG_PCI_P2PDMA, ns->queue);
 
 	ns->ctrl = ctrl;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 9871c0c9374c..fb9bfc52a6d7 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -477,7 +477,6 @@  struct nvme_ctrl_ops {
 	unsigned int flags;
 #define NVME_F_FABRICS			(1 << 0)
 #define NVME_F_METADATA_SUPPORTED	(1 << 1)
-#define NVME_F_PCI_P2PDMA		(1 << 2)
 	int (*reg_read32)(struct nvme_ctrl *ctrl, u32 off, u32 *val);
 	int (*reg_write32)(struct nvme_ctrl *ctrl, u32 off, u32 val);
 	int (*reg_read64)(struct nvme_ctrl *ctrl, u32 off, u64 *val);
@@ -485,6 +484,7 @@  struct nvme_ctrl_ops {
 	void (*submit_async_event)(struct nvme_ctrl *ctrl);
 	void (*delete_ctrl)(struct nvme_ctrl *ctrl);
 	int (*get_address)(struct nvme_ctrl *ctrl, char *buf, int size);
+	bool (*supports_pci_p2pdma)(struct nvme_ctrl *ctrl);
 };
 
 /*
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index b82492cd7503..7d1ef66eac2e 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2874,17 +2874,24 @@  static int nvme_pci_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
 	return snprintf(buf, size, "%s\n", dev_name(&pdev->dev));
 }
 
+static bool nvme_pci_supports_pci_p2pdma(struct nvme_ctrl *ctrl)
+{
+	struct nvme_dev *dev = to_nvme_dev(ctrl);
+
+	return dma_pci_p2pdma_supported(dev->dev);
+}
+
 static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = {
 	.name			= "pcie",
 	.module			= THIS_MODULE,
-	.flags			= NVME_F_METADATA_SUPPORTED |
-				  NVME_F_PCI_P2PDMA,
+	.flags			= NVME_F_METADATA_SUPPORTED,
 	.reg_read32		= nvme_pci_reg_read32,
 	.reg_write32		= nvme_pci_reg_write32,
 	.reg_read64		= nvme_pci_reg_read64,
 	.free_ctrl		= nvme_pci_free_ctrl,
 	.submit_async_event	= nvme_pci_submit_async_event,
 	.get_address		= nvme_pci_get_address,
+	.supports_pci_p2pdma	= nvme_pci_supports_pci_p2pdma,
 };
 
 static int nvme_dev_map(struct nvme_dev *dev)