[PATCH 0/4] nvme: add ctrl sgl supported helper

[PATCH 0/4] nvme: add ctrl sgl supported helper

[Chaitanya Kulkarni]

Hi,

For various transports such as fc/tcp/pci it is common to check if
NVMe SGLs are supported or not by the controller.

Instead of open coding that check add nvme_ctrl_sgl_supported()
helper and use it in the respective transports on the host side.

-ck

Chaitanya Kulkarni (4):
  nvme: add a helper to check ctrl sgl support
  nvme-fc: use ctrl sgl check helper
  nvm-pci: use ctrl sgl check helper
  nvme-tcp: use ctrl sgl check helper

 drivers/nvme/host/fc.c   | 2 +-
 drivers/nvme/host/nvme.h | 8 ++++++++
 drivers/nvme/host/pci.c  | 4 ++--
 drivers/nvme/host/tcp.c  | 2 +-
 4 files changed, 12 insertions(+), 4 deletions(-)

-- 
2.22.1


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[PATCH 1/4] nvme: add a helper to check ctrl sgl support

[Chaitanya Kulkarni]

For various transports such as fc/tcp/pci it is common to check if
NVMe SGLs are supported or not by the controller.

In this preparation patch we add a helper to avoid the open coding of
such checks in the various transport.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/nvme/host/nvme.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 1f397ecba16c..1aab74128d40 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -869,6 +869,14 @@ static inline void nvme_hwmon_exit(struct nvme_ctrl *ctrl)
 }
 #endif
 
+static inline bool nvme_ctrl_sgl_supported(struct nvme_ctrl *ctrl)
+{
+	if (!(ctrl->sgls & ((1 << 0) | (1 << 1))))
+		return true;
+
+	return false;
+}
+
 u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 			 u8 opcode);
 void nvme_execute_passthru_rq(struct request *rq);
-- 
2.22.1


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[PATCH 2/4] nvme-fc: use ctrl sgl check helper

[Chaitanya Kulkarni]

Use the helper to check NVMe controller's SGL support.

Reviewed-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/nvme/host/fc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index f183f9fa03d0..7600863f7752 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -3112,7 +3112,7 @@ nvme_fc_create_association(struct nvme_fc_ctrl *ctrl)
 	}
 
 	/* FC-NVME supports normal SGL Data Block Descriptors */
-	if (!(ctrl->ctrl.sgls & ((1 << 0) | (1 << 1)))) {
+	if (!nvme_ctrl_sgl_supported(&ctrl->ctrl)) {
 		dev_err(ctrl->ctrl.device,
 			"Mandatory sgls are not supported!\n");
 		ret = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
-- 
2.22.1


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[PATCH 3/4] nvm-pci: use ctrl sgl check helper

[Chaitanya Kulkarni]

Use the helper to check NVMe controller's SGL support.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/nvme/host/pci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index c5356028199d..5df1adc5a1db 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -536,7 +536,7 @@ static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req)
 
 	avg_seg_size = DIV_ROUND_UP(blk_rq_payload_bytes(req), nseg);
 
-	if (!(dev->ctrl.sgls & ((1 << 0) | (1 << 1))))
+	if (!nvme_ctrl_sgl_supported(&dev->ctrl))
 		return false;
 	if (!iod->nvmeq->qid)
 		return false;
@@ -853,7 +853,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 							     &cmnd->rw, &bv);
 
 			if (iod->nvmeq->qid && sgl_threshold &&
-			    dev->ctrl.sgls & ((1 << 0) | (1 << 1)))
+			    nvme_ctrl_sgl_supported(&dev->ctrl))
 				return nvme_setup_sgl_simple(dev, req,
 							     &cmnd->rw, &bv);
 		}
-- 
2.22.1


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[PATCH 4/4] nvme-tcp: use ctrl sgl check helper

[Chaitanya Kulkarni]

Use the helper to check NVMe controller's SGL support.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/nvme/host/tcp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 6a65b0516180..c7bd37103cf4 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1993,7 +1993,7 @@ static int nvme_tcp_setup_ctrl(struct nvme_ctrl *ctrl, bool new)
 		goto destroy_admin;
 	}
 
-	if (!(ctrl->sgls & ((1 << 0) | (1 << 1)))) {
+	if (!nvme_ctrl_sgl_supported(ctrl)) {
 		ret = -EOPNOTSUPP;
 		dev_err(ctrl->device, "Mandatory sgls are not supported!\n");
 		goto destroy_admin;
-- 
2.22.1


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Re: [PATCH 0/4] nvme: add ctrl sgl supported helper

[Christoph Hellwig]

Thanks,

applied to nvme-5.14.

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Re: [PATCH 4/4] nvme-tcp: use ctrl sgl check helper

[Prabhakar Kushwaha]

Hi Chaitanya,

On Thu, Jun 10, 2021 at 7:04 AM Chaitanya Kulkarni
<chaitanya.kulkarni@wdc.com> wrote:
>
> Use the helper to check NVMe controller's SGL support.
>
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
> ---
>  drivers/nvme/host/tcp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index 6a65b0516180..c7bd37103cf4 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -1993,7 +1993,7 @@ static int nvme_tcp_setup_ctrl(struct nvme_ctrl *ctrl, bool new)
>                 goto destroy_admin;
>         }
>
> -       if (!(ctrl->sgls & ((1 << 0) | (1 << 1)))) {
> +       if (!nvme_ctrl_sgl_supported(ctrl)) {
>                 ret = -EOPNOTSUPP;
>                 dev_err(ctrl->device, "Mandatory sgls are not supported!\n");
>                 goto destroy_admin;
> --
> 2.22.1
>
>

base patch defines nvme_ctrl_sgl_supported as below
 +static inline bool nvme_ctrl_sgl_supported(struct nvme_ctrl *ctrl)
 +{
 +    if (!(ctrl->sgls & ((1 << 0) | (1 << 1))))
 +        return true;
 +
 +    return false;
 +}

The "!" is already part of nvme_ctrl_sgl_supported(). There is no
point in keeping "!" at other places.
So, either remove "!" from other places or from nvme_ctrl_sgl_supported().

I request you to check the logic again.
In case you are planning to fix, the best place would be
nvme_ctrl_sgl_supported() to have minimal changes.

 -pk

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Re: [PATCH 4/4] nvme-tcp: use ctrl sgl check helper

[Chaitanya Kulkarni]

> On Jun 16, 2021, at 6:37 PM, Prabhakar Kushwaha <prabhakar.pkin@gmail.com> wrote:
> 
> Hi Chaitanya,
> 
>> On Thu, Jun 10, 2021 at 7:04 AM Chaitanya Kulkarni
>> <chaitanya.kulkarni@wdc.com> wrote:
>> 
>> Use the helper to check NVMe controller's SGL support.
>> 
>> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
>> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
>> ---
>> drivers/nvme/host/tcp.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
>> index 6a65b0516180..c7bd37103cf4 100644
>> --- a/drivers/nvme/host/tcp.c
>> +++ b/drivers/nvme/host/tcp.c
>> @@ -1993,7 +1993,7 @@ static int nvme_tcp_setup_ctrl(struct nvme_ctrl *ctrl, bool new)
>>                goto destroy_admin;
>>        }
>> 
>> -       if (!(ctrl->sgls & ((1 << 0) | (1 << 1)))) {
>> +       if (!nvme_ctrl_sgl_supported(ctrl)) {
>>                ret = -EOPNOTSUPP;
>>                dev_err(ctrl->device, "Mandatory sgls are not supported!\n");
>>                goto destroy_admin;
>> --
>> 2.22.1
>> 
>> 
> 
> base patch defines nvme_ctrl_sgl_supported as below
> +static inline bool nvme_ctrl_sgl_supported(struct nvme_ctrl *ctrl)
> +{
> +    if (!(ctrl->sgls & ((1 << 0) | (1 << 1))))
> +        return true;
> +
> +    return false;
> +}
> 
> The "!" is already part of nvme_ctrl_sgl_supported(). There is no
> point in keeping "!" at other places.
> So, either remove "!" from other places or from nvme_ctrl_sgl_supported().
> 
> I request you to check the logic again.
> In case you are planning to fix, the best place would be
> nvme_ctrl_sgl_supported() to have minimal changes.
> 
> -pk


Thanks for pointing this out. I'll send out the fix shortly. 

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