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Date: Mon, 15 Apr 2024 13:13:05 -0300
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Shradha Gupta <shradhagupta@linux.microsoft.com>
Cc: linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Ajay Sharma <sharmaajay@microsoft.com>,
	Leon Romanovsky <leon@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Long Li <longli@microsoft.com>,
	Michael Kelley <mikelley@microsoft.com>,
	Shradha Gupta <shradhagupta@microsoft.com>,
	Yury Norov <yury.norov@gmail.com>,
	Konstantin Taranov <kotaranov@microsoft.com>,
	Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
Subject: Re: [PATCH net-next] net: mana: Add new device attributes for mana
Message-ID: <20240415161305.GO223006@ziepe.ca>
References: <1713174589-29243-1-git-send-email-shradhagupta@linux.microsoft.com>
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In-Reply-To: <1713174589-29243-1-git-send-email-shradhagupta@linux.microsoft.com>

On Mon, Apr 15, 2024 at 02:49:49AM -0700, Shradha Gupta wrote:
> Add new device attributes to view multiport, msix, and adapter MTU
> setting for MANA device.
> 
> Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> ---
>  .../net/ethernet/microsoft/mana/gdma_main.c   | 74 +++++++++++++++++++
>  include/net/mana/gdma.h                       |  9 +++
>  2 files changed, 83 insertions(+)
> 
> diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> index 1332db9a08eb..6674a02cff06 100644
> --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> @@ -1471,6 +1471,65 @@ static bool mana_is_pf(unsigned short dev_id)
>  	return dev_id == MANA_PF_DEVICE_ID;
>  }
>  
> +static ssize_t mana_attr_show(struct device *dev,
> +			      struct device_attribute *attr, char *buf)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct gdma_context *gc = pci_get_drvdata(pdev);
> +	struct mana_context *ac = gc->mana.driver_data;
> +
> +	if (strcmp(attr->attr.name, "mport") == 0)
> +		return snprintf(buf, PAGE_SIZE, "%d\n", ac->num_ports);
> +	else if (strcmp(attr->attr.name, "adapter_mtu") == 0)
> +		return snprintf(buf, PAGE_SIZE, "%d\n", gc->adapter_mtu);
> +	else if (strcmp(attr->attr.name, "msix") == 0)
> +		return snprintf(buf, PAGE_SIZE, "%d\n", gc->max_num_msix);
> +	else
> +		return -EINVAL;
> +

That is not how sysfs should be implemented at all, please find a
good example to copy from. Every attribute should use its own function
with the macros to link it into an attributes group and sysfs_emit
should be used for printing

Jason