Message-ID: <20240903163519.GAZtc6x7o9Cy1MQAsb@fat_crate.local>
Date: Tue, 3 Sep 2024 18:35:19 +0200
From: Borislav Petkov <bp@...en8.de>
To: shiju.jose@...wei.com
Cc: linux-edac@...r.kernel.org, linux-cxl@...r.kernel.org,
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Subject: Re: [PATCH v11 01/14] EDAC: Add support for EDAC device feature's
 control

On Fri, Aug 16, 2024 at 05:42:24PM +0100, shiju.jose@...wei.com wrote:
> From: Shiju Jose <shiju.jose@...wei.com>
> 
> Add generic EDAC device feature's control supports registering

"features"

Check your whole set.

> RAS features supported in the system. Driver exposes feature's
> control attributes to the userspace in

s/the //

> /sys/bus/edac/devices/<dev-name>/<ras-feature>/
> 
> Co-developed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Signed-off-by: Shiju Jose <shiju.jose@...wei.com>
> ---
>  drivers/edac/edac_device.c | 178 +++++++++++++++++++++++++++++++++++++
>  include/linux/edac.h       |  60 +++++++++++++
>  2 files changed, 238 insertions(+)
> 
> diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
> index 621dc2a5d034..635a41db8b5a 100644
> --- a/drivers/edac/edac_device.c
> +++ b/drivers/edac/edac_device.c
> @@ -570,3 +570,181 @@ void edac_device_handle_ue_count(struct edac_device_ctl_info *edac_dev,
>  		      block ? block->name : "N/A", count, msg);
>  }
>  EXPORT_SYMBOL_GPL(edac_device_handle_ue_count);
> +
> +/* EDAC device feature */
> +static void edac_dev_release(struct device *dev)
> +{
> +	struct edac_dev_feat_ctx *ctx =
> +		container_of(dev, struct edac_dev_feat_ctx, dev);

Ew, no, don't do such silly linebreaks pls.

> +	kfree(ctx->dev.groups);
> +	kfree(ctx);
> +}
> +
> +const struct device_type edac_dev_type = {
> +	.name = "edac_dev",
> +	.release = edac_dev_release,
> +};
> +
> +static void edac_dev_unreg(void *data)
> +{
> +	device_unregister(data);
> +}
> +
> +/**
> + * edac_dev_feature_init - Init a ras feature

s/ras/RAS/g

Check your whole set.

> + * @parent: client device.
> + * @dev_data: pointer to struct edac_dev_data.

I can see it is a pointer. What it is used for?

> + * @feat: pointer to struct edac_dev_feature.
> + * @attr_groups: pointer to attribute group's container.
> + *
> + * Returns number of scrub feature's attribute groups on success,
> + * error otherwise.
> + */
> +static int edac_dev_feat_init(struct device *parent,
> +			      struct edac_dev_data *dev_data,
> +			      const struct edac_dev_feature *ras_feat,
> +			      const struct attribute_group **attr_groups)
> +{
> +	int num;
> +
> +	switch (ras_feat->feat) {
> +	case RAS_FEAT_SCRUB:
> +		dev_data->scrub_ops = ras_feat->scrub_ops;
> +		dev_data->private = ras_feat->scrub_ctx;
> +		return 1;
> +	case RAS_FEAT_ECS:
> +		num = ras_feat->ecs_info.num_media_frus;
> +		dev_data->ecs_ops = ras_feat->ecs_ops;
> +		dev_data->private = ras_feat->ecs_ctx;
> +		return num;
> +	case RAS_FEAT_PPR:
> +		dev_data->ppr_ops = ras_feat->ppr_ops;
> +		dev_data->private = ras_feat->ppr_ctx;
> +		return 1;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +/**
> + * edac_dev_register - register device for ras features with edac

s/edac/EDAC/g

Check your whole set.

> + * @parent: client device.
> + * @name: client device's name.
> + * @private: parent driver's data to store in the context if any.
> + * @num_features: number of ras features to register.
> + * @ras_features: list of ras features to register.
> + *
> + * Returns 0 on success, error otherwise.
> + * The new edac_dev_feat_ctx would be freed automatically.
> + */
> +int edac_dev_register(struct device *parent, char *name,
> +		      void *private, int num_features,
> +		      const struct edac_dev_feature *ras_features)
> +{
> +	const struct attribute_group **ras_attr_groups;
> +	struct edac_dev_data *dev_data;
> +	struct edac_dev_feat_ctx *ctx;
> +	int ppr_cnt = 0, ppr_inst = 0;
> +	int attr_gcnt = 0;
> +	int ret, feat;
> +
> +	if (!parent || !name || !num_features || !ras_features)
> +		return -EINVAL;
> +
> +	/* Double parse so we can make space for attributes */

Who's "we"?

Please use passive voice in your comments: no "we" or "I", etc.

Personal pronouns are ambiguous in text, especially with so many
parties/companies/etc developing the kernel so let's avoid them please.

> +	for (feat = 0; feat < num_features; feat++) {
> +		switch (ras_features[feat].feat) {
> +		case RAS_FEAT_SCRUB:

Does this need "fallthrough;" or somesuch?

> +		case RAS_FEAT_PPR:
> +			attr_gcnt++;
> +			ppr_cnt++;
> +			break;
> +		case RAS_FEAT_ECS:
> +			attr_gcnt += ras_features[feat].ecs_info.num_media_frus;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +
> +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx)
> +		return -ENOMEM;
> +
> +	ctx->dev.parent = parent;
> +	ctx->private = private;
> +
> +	ras_attr_groups = kcalloc(attr_gcnt + 1, sizeof(*ras_attr_groups), GFP_KERNEL);
> +	if (!ras_attr_groups) {
> +		ret = -ENOMEM;
> +		goto ctx_free;
> +	}
> +
> +	if (ppr_cnt) {
> +		ctx->ppr = kcalloc(ppr_cnt, sizeof(*(ctx->ppr)), GFP_KERNEL);
> +		if (!ctx->ppr) {
> +			ret = -ENOMEM;
> +			goto groups_free;
> +		}
> +	}
> +
> +	attr_gcnt = 0;
> +	for (feat = 0; feat < num_features; feat++, ras_features++) {
> +		switch (ras_features->feat) {
> +		case RAS_FEAT_SCRUB:
> +			if (!ras_features->scrub_ops)
> +				continue;
> +			dev_data = &ctx->scrub;
> +			break;
> +		case RAS_FEAT_ECS:
> +			if (!ras_features->ecs_ops)
> +				continue;
> +			dev_data = &ctx->ecs;
> +			break;
> +		case RAS_FEAT_PPR:
> +			if (!ras_features->ppr_ops)
> +				continue;
> +			dev_data = &ctx->ppr[ppr_inst];
> +			dev_data->instance = ppr_inst;
> +			ppr_inst++;
> +			break;
> +		default:
> +			ret = -EINVAL;
> +			goto data_mem_free;
> +		}
> +		ret = edac_dev_feat_init(parent, dev_data, ras_features,
> +					 &ras_attr_groups[attr_gcnt]);
> +		if (ret < 0)
> +			goto data_mem_free;
> +
> +		attr_gcnt += ret;
> +	}

Newline.

> +	ras_attr_groups[attr_gcnt] = NULL;
> +	ctx->dev.bus = edac_get_sysfs_subsys();
> +	ctx->dev.type = &edac_dev_type;
> +	ctx->dev.groups = ras_attr_groups;
> +	dev_set_drvdata(&ctx->dev, ctx);

Ditto.

> +	ret = dev_set_name(&ctx->dev, name);
> +	if (ret)
> +		goto data_mem_free;
> +
> +	ret = device_register(&ctx->dev);
> +	if (ret) {
> +		put_device(&ctx->dev);
> +		goto data_mem_free;
> +		return ret;
> +	}
> +
> +	return devm_add_action_or_reset(parent, edac_dev_unreg, &ctx->dev);
> +
> +data_mem_free:
> +	if (ppr_cnt)
> +		kfree(ctx->ppr);
> +groups_free:
> +	kfree(ras_attr_groups);
> +ctx_free:
> +	kfree(ctx);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(edac_dev_register);
> diff --git a/include/linux/edac.h b/include/linux/edac.h
> index b4ee8961e623..cc96f55ac714 100644
> --- a/include/linux/edac.h
> +++ b/include/linux/edac.h
> @@ -661,4 +661,64 @@ static inline struct dimm_info *edac_get_dimm(struct mem_ctl_info *mci,
>  
>  	return mci->dimms[index];
>  }
> +
> +/* EDAC device features */
> +
> +#define EDAC_FEAT_NAME_LEN	128
> +
> +enum edac_dev_feat {
> +	RAS_FEAT_SCRUB,
> +	RAS_FEAT_ECS,
> +	RAS_FEAT_PPR,

What are those? Comments ontop explaining pls.

> +	RAS_FEAT_MAX
> +};
> +
> +struct edac_ecs_ex_info {
> +	u16 num_media_frus;
> +};
> +
> +/*
> + * EDAC device feature information structure
> + */
> +struct edac_dev_data {
> +	union {
> +		const struct edac_scrub_ops *scrub_ops;
> +		const struct edac_ecs_ops *ecs_ops;
> +		const struct edac_ppr_ops *ppr_ops;
> +	};
> +	u8 instance;
> +	void *private;
> +};
> +
> +struct device;
> +
> +struct edac_dev_feat_ctx {
> +	struct device dev;
> +	void *private;
> +	struct edac_dev_data scrub;
> +	struct edac_dev_data ecs;
> +	struct edac_dev_data *ppr;
> +};
> +
> +struct edac_dev_feature {
> +	enum edac_dev_feat feat;

			ft_type;

> +	u8 instance;
> +	union {
> +		const struct edac_scrub_ops *scrub_ops;
> +		const struct edac_ecs_ops *ecs_ops;
> +		const struct edac_ppr_ops *ppr_ops;
> +	};
> +	union {
> +		void *scrub_ctx;
> +		void *ecs_ctx;
> +		void *ppr_ctx;
> +	};

Or drop the silly union and simply do

	void *ctx;

> +	union {
> +		struct edac_ecs_ex_info ecs_info;
> +	};

Union with a single member?!

> +};
> +
> +int edac_dev_register(struct device *parent, char *dev_name,
> +		      void *parent_pvt_data, int num_features,
> +		      const struct edac_dev_feature *ras_features);
>  #endif /* _LINUX_EDAC_H_ */
> -- 
> 2.34.1
> 

-- 
Regards/Gruss,
    Boris.

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