Re: [PATCH v4 02/11] mtd: add driver for intel graphics non-volatile memory device

[Christophe JAILLET]

Le 01/01/2025 à 16:39, Alexander Usyskin a écrit :
> Add auxiliary driver for intel discrete graphics
> non-volatile memory device.
>
> CC: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> Co-developed-by: Tomas Winkler <tomasw@xxxxxxxxx>
> Signed-off-by: Tomas Winkler <tomasw@xxxxxxxxx>
> Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

...

> +struct intel_dg_nvm {
> +	struct kref refcnt;
> +	void __iomem *base;
> +	size_t size;
> +	unsigned int nregions;
> +	struct {
> +		const char *name;
> +		u8 id;
> +		u64 offset;
> +		u64 size;
> +	} regions[];

__counted_by(nregions)?

> +};
> +
> +static void intel_dg_nvm_release(struct kref *kref)
> +{
> +	struct intel_dg_nvm *nvm = container_of(kref, struct intel_dg_nvm, refcnt);
> +	int i;
> +
> +	pr_debug("freeing intel_dg nvm\n");
> +	for (i = 0; i < nvm->nregions; i++)
> +		kfree(nvm->regions[i].name);
> +	kfree(nvm);
> +}
> +
> +static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
> +			      const struct auxiliary_device_id *aux_dev_id)
> +{
> +	struct intel_dg_nvm_dev *invm = auxiliary_dev_to_intel_dg_nvm_dev(aux_dev);
> +	struct device *device;
> +	struct intel_dg_nvm *nvm;
> +	unsigned int nregions;
> +	unsigned int i, n;
> +	size_t size;
> +	char *name;
> +	int ret;
> +
> +	device = &aux_dev->dev;
> +
> +	/* count available regions */
> +	for (nregions = 0, i = 0; i < INTEL_DG_NVM_REGIONS; i++) {
> +		if (invm->regions[i].name)
> +			nregions++;
> +	}
> +
> +	if (!nregions) {
> +		dev_err(device, "no regions defined\n");
> +		return -ENODEV;
> +	}
> +
> +	size = sizeof(*nvm) + sizeof(nvm->regions[0]) * nregions;

struct_size()? (and maybe no need for size)

> +	nvm = kzalloc(size, GFP_KERNEL);
> +	if (!nvm)
> +		return -ENOMEM;
> +
> +	kref_init(&nvm->refcnt);
> +
> +	nvm->nregions = nregions;
> +	for (n = 0, i = 0; i < INTEL_DG_NVM_REGIONS; i++) {
> +		if (!invm->regions[i].name)
> +			continue;
> +
> +		name = kasprintf(GFP_KERNEL, "%s.%s",
> +				 dev_name(&aux_dev->dev), invm->regions[i].name);
> +		if (!name)
> +			continue;
> +		nvm->regions[n].name = name;
> +		nvm->regions[n].id = i;
> +		n++;
> +	}

Should we set the exact number of regions, should a kasprintf() fail?
	nvm->nregions = n;
This would make __counted_by be more accurate in its check.

> +
> +	nvm->base = devm_ioremap_resource(device, &invm->bar);
> +	if (IS_ERR(nvm->base)) {
> +		dev_err(device, "mmio not mapped\n");
> +		ret = PTR_ERR(nvm->base);
> +		goto err;
> +	}
> +
> +	dev_set_drvdata(&aux_dev->dev, nvm);
> +
> +	return 0;
> +
> +err:
> +	kref_put(&nvm->refcnt, intel_dg_nvm_release);
> +	return ret;
> +}

...

CJ