On 19-06-24 22:29:05, Weiping Zhang wrote:
> The get_ams() will return the AMS(Arbitration Mechanism Selected)
> from the driver.
>
> Signed-off-by: Weiping Zhang <zhangweiping@xxxxxxxxxxxxxx>
Hello, Weiping.
Sorry, but I don't really get what your point is here. Could you please
elaborate this patch a little bit more? The commit description just
says a function would just return the AMS from nowhere..
> ---
> drivers/nvme/host/core.c | 9 ++++++++-
> drivers/nvme/host/nvme.h | 1 +
> drivers/nvme/host/pci.c | 6 ++++++
> include/linux/nvme.h | 1 +
> 4 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index b2dd4e391f5c..4cb781e73123 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -1943,6 +1943,7 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
> */
> unsigned dev_page_min = NVME_CAP_MPSMIN(cap) + 12, page_shift = 12;
> int ret;
> + u32 ams = NVME_CC_AMS_RR;
>
> if (page_shift < dev_page_min) {
> dev_err(ctrl->device,
> @@ -1951,11 +1952,17 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
> return -ENODEV;
> }
>
> + /* get Arbitration Mechanism Selected */
> + if (ctrl->ops->get_ams) {
I just wonder if this check will be valid because this patch just
register the function nvme_pci_get_ams() without any conditions.
> + ctrl->ops->get_ams(ctrl, &ams);
> + ams &= NVME_CC_AMS_MASK;
> + }
> +
> ctrl->page_size = 1 << page_shift;
>
> ctrl->ctrl_config = NVME_CC_CSS_NVM;
> ctrl->ctrl_config |= (page_shift - 12) << NVME_CC_MPS_SHIFT;
> - ctrl->ctrl_config |= NVME_CC_AMS_RR | NVME_CC_SHN_NONE;
> + ctrl->ctrl_config |= ams | NVME_CC_SHN_NONE;
> ctrl->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
> ctrl->ctrl_config |= NVME_CC_ENABLE;
>
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index ea45d7d393ad..9c7e9217f78b 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -369,6 +369,7 @@ 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);
> + void (*get_ams)(struct nvme_ctrl *ctrl, u32 *ams);
Can we just have a return value for the AMS value?
> };
>
> #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 189352081994..5d84241f0214 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2627,6 +2627,11 @@ static int nvme_pci_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
> return snprintf(buf, size, "%s", dev_name(&pdev->dev));
> }
>
> +static void nvme_pci_get_ams(struct nvme_ctrl *ctrl, u32 *ams)
> +{
> + *ams = NVME_CC_AMS_RR;
> +}
> +
> static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = {
> .name = "pcie",
> .module = THIS_MODULE,
> @@ -2638,6 +2643,7 @@ static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = {
> .free_ctrl = nvme_pci_free_ctrl,
> .submit_async_event = nvme_pci_submit_async_event,
> .get_address = nvme_pci_get_address,
> + .get_ams = nvme_pci_get_ams,
Question: Do we really need this being added to nvme_ctrl_ops?
Also If 5th patch will make this function much more than this, then it
would be great if you describe this kind of situation in description :)
> };
>
> static int nvme_dev_map(struct nvme_dev *dev)
> diff --git a/include/linux/nvme.h b/include/linux/nvme.h
> index da5f696aec00..8f71451fc2fa 100644
> --- a/include/linux/nvme.h
> +++ b/include/linux/nvme.h
> @@ -156,6 +156,7 @@ enum {
> NVME_CC_AMS_RR = 0 << NVME_CC_AMS_SHIFT,
> NVME_CC_AMS_WRRU = 1 << NVME_CC_AMS_SHIFT,
> NVME_CC_AMS_VS = 7 << NVME_CC_AMS_SHIFT,
> + NVME_CC_AMS_MASK = 7 << NVME_CC_AMS_SHIFT,
> NVME_CC_SHN_NONE = 0 << NVME_CC_SHN_SHIFT,
> NVME_CC_SHN_NORMAL = 1 << NVME_CC_SHN_SHIFT,
> NVME_CC_SHN_ABRUPT = 2 << NVME_CC_SHN_SHIFT,
> --
> 2.14.1
>
