[PATCH V2] nvme: expose active quirks in sysfs

[Sagi Grimberg]

On 03/11/2025 16:44, Maurizio Lombardi wrote:
> Currently, there is no straightforward way for a user to inspect
> which quirks are active for a given device from userspace.
>
> Add a new "quirks" sysfs attribute to the nvme controller device.
>
> Reading this file will display a human-readable list
> of all active quirks, with each quirk name on a new line.
> If no quirks are active, it will display "none".
>
> Signed-off-by: Maurizio Lombardi <mlombard at redhat.com>
> ---
>
> V2: Do not expose kernel-internal constants to userspace.
>      Move the quirks attribute to the controller device, where it belongs.
>
>   drivers/nvme/host/nvme.h  | 54 +++++++++++++++++++++++++++++++++++++++
>   drivers/nvme/host/sysfs.c | 23 +++++++++++++++++
>   2 files changed, 77 insertions(+)
>
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 102fae6a231c..647f19dd57e9 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -180,6 +180,60 @@ enum nvme_quirks {
>   	NVME_QUIRK_DMAPOOL_ALIGN_512		= (1 << 22),
>   };
>   
> +static inline char *nvme_quirk_name(enum nvme_quirks q)
> +{
> +	switch (q) {
> +	case NVME_QUIRK_STRIPE_SIZE:
> +		return "stripe_size";
> +	case NVME_QUIRK_IDENTIFY_CNS:
> +		return "identify_cns";
> +	case NVME_QUIRK_DEALLOCATE_ZEROES:
> +		return "deallocate_zeroes";
> +	case NVME_QUIRK_DELAY_BEFORE_CHK_RDY:
> +		return "delay_before_chk_rdy";
> +	case NVME_QUIRK_NO_APST:
> +		return "no_apst";
> +	case NVME_QUIRK_NO_DEEPEST_PS:
> +		return "no_deepest_ps";
> +	case NVME_QUIRK_QDEPTH_ONE:
> +		return "qdepth_one";
> +	case NVME_QUIRK_MEDIUM_PRIO_SQ:
> +		return "medium_prio_sq";
> +	case NVME_QUIRK_IGNORE_DEV_SUBNQN:
> +		return "ignore_dev_subnqn";
> +	case NVME_QUIRK_DISABLE_WRITE_ZEROES:
> +		return "disable_write_zeroes";
> +	case NVME_QUIRK_SIMPLE_SUSPEND:
> +		return "simple_suspend";
> +	case NVME_QUIRK_SINGLE_VECTOR:
> +		return "single_vector";
> +	case NVME_QUIRK_128_BYTES_SQES:
> +		return "128_bytes_sqes";
> +	case NVME_QUIRK_SHARED_TAGS:
> +		return "shared_tags";
> +	case NVME_QUIRK_NO_TEMP_THRESH_CHANGE:
> +		return "no_temp_thresh_change";
> +	case NVME_QUIRK_NO_NS_DESC_LIST:
> +		return "no_ns_desc_list";
> +	case NVME_QUIRK_DMA_ADDRESS_BITS_48:
> +		return "dma_address_bits_48";
> +	case NVME_QUIRK_SKIP_CID_GEN:
> +		return "skip_cid_gen";
> +	case NVME_QUIRK_BOGUS_NID:
> +		return "bogus_nid";
> +	case NVME_QUIRK_NO_SECONDARY_TEMP_THRESH:
> +		return "no_secondary_temp_thresh";
> +	case NVME_QUIRK_FORCE_NO_SIMPLE_SUSPEND:
> +		return "force_no_simple_suspend";
> +	case NVME_QUIRK_BROKEN_MSI:
> +		return "broken_msi";
> +	case NVME_QUIRK_DMAPOOL_ALIGN_512:
> +		return "dmapool_align_512";
> +	}
> +
> +	return "unknown";

How about simply print the value/bit in this case?

Other than that, looks fine,
Reviewed-by: Sagi Grimberg <sagi at grimberg.me>