Re: [PATCH 2/2] nvme: improve cmb sysfs reporting

Jon Derrick
2016-12-19T15:43:00Z

Minor nit below

On Fri, Dec 16, 2016 at 11:54:51AM -0700, Stephen Bates wrote:
> Add more information to the NVMe CMB sysfs entry. This includes
> information about the CMB size, location and capabilities.
>
> Signed-off-by: Stephen Bates <sbates@raithlin.com>
> ---
> drivers/nvme/host/pci.c | 31 +++++++++++++++++++++++++++++--
> include/linux/nvme.h | 8 ++++++++
> 2 files changed, 37 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index be10860..1f70630 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -98,6 +98,7 @@ struct nvme_dev {
> void __iomem *cmb;
> dma_addr_t cmb_dma_addr;
> u64 cmb_size;
> + u64 cmb_offset;
> u32 cmbsz;
> u32 cmbloc;
> struct nvme_ctrl ctrl;
> @@ -1326,14 +1327,39 @@ static int nvme_create_io_queues(struct nvme_dev *dev)
> return ret >= 0 ? 0 : ret;
> }
>
> +static const char * const cmb_caps[] = {
> + [NVME_CMB_CAP_SQS] = "SQS",
> + [NVME_CMB_CAP_CQS] = "CQS",
> + [NVME_CMB_CAP_LISTS] = "LISTS",
> + [NVME_CMB_CAP_RDS] = "RDS",
> + [NVME_CMB_CAP_WDS] = "WDS",
> +};
> +
> static ssize_t nvme_cmb_show(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> {
> struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
> + unsigned int i, len = 0;
> +
> + len += scnprintf(buf+len, PAGE_SIZE-len,
> + "cmbloc : 0x%08x\ncmbsz : 0x%08x\n\n",
> + ndev->cmbloc, ndev->cmbsz);
> +
> + len += scnprintf(buf+len, PAGE_SIZE-len,
> + "OFFSET : 0x%016llx\nSIZE : %llu Bytes\n" \
> + "DMA ADDR : %pad\n\n",
> + ndev->cmb_offset, ndev->cmb_size,
> + &ndev->cmb_dma_addr);
> +
> + for (i = NVME_CMB_CAP_SQS; i <= NVME_CMB_CAP_WDS; i++)
I'd prefer seeing (i = 0; i < ARRAY_SIZE(..); i++) because it provides
automatic bounds checking against future code.

> + len += scnprintf(buf+len, PAGE_SIZE-len, "%-7s: %s\n",
> + cmb_caps[i],
> + ((ndev->cmbsz) & (1<<i)) ? "SUPPORTED" :
> + "NOT SUPPORTED");
> +
> + return len;
>
> - return scnprintf(buf, PAGE_SIZE, "cmbloc : x%08x\ncmbsz : x%08x\n",
> - ndev->cmbloc, ndev->cmbsz);
> }
> static DEVICE_ATTR(cmb, S_IRUGO, nvme_cmb_show, NULL);
>
> @@ -1376,6 +1402,7 @@ static void __iomem *nvme_map_cmb(struct nvme_dev *dev)
>
> dev->cmb_dma_addr = dma_addr;
> dev->cmb_size = size;
> + dev->cmb_offset = offset;
> return cmb;
> }
>
> diff --git a/include/linux/nvme.h b/include/linux/nvme.h
> index fc3c242..cd0d324 100644
> --- a/include/linux/nvme.h
> +++ b/include/linux/nvme.h
> @@ -121,6 +121,14 @@ enum {
> #define NVME_CMB_CQS(cmbsz) ((cmbsz) & 0x2)
> #define NVME_CMB_SQS(cmbsz) ((cmbsz) & 0x1)
>
> +enum {
> + NVME_CMB_CAP_SQS = 0,
> + NVME_CMB_CAP_CQS,
> + NVME_CMB_CAP_LISTS,
> + NVME_CMB_CAP_RDS,
> + NVME_CMB_CAP_WDS,
> +};
> +
> /*
> * Submission and Completion Queue Entry Sizes for the NVM command set.
> * (In bytes and specified as a power of two (2^n)).
> --
> 2.1.4
>