Re: [PATCH v3 3/4] driver property: constify property arrays values

Joe Perches
2017-02-01T23:30:03Z

On Wed, 2017-02-01 at 09:31 -0800, Dmitry Torokhov wrote:
> Data that is fed into property arrays should not be modified, so let's mark
> relevant pointers as const. This will allow us making source arrays as
> const/__initconst.

trivia:

> diff --git a/drivers/base/property.c b/drivers/base/property.c
[]
> @@ -682,44 +682,66 @@ int fwnode_property_match_string(struct fwnode_handle *fwnode,
> }
> EXPORT_SYMBOL_GPL(fwnode_property_match_string);
>
> +static int property_copy_string_array(struct property_entry *dst,
> + const struct property_entry *src)
> +{
> + char **d;
> + size_t nval = src->length / sizeof(*d);
> + size_t i;
> +
> + d = kcalloc(nval, sizeof(*d), GFP_KERNEL);
> + if (!d)
> + return -ENOMEM;
> +
> + for (i = 0; i < nval; i++) {
> + d[i] = kstrdup(src->pointer.str[i], GFP_KERNEL);
> + if (!d[i] && src->pointer.str[i]) {
> + while (--i >= 0)
> + kfree(d[i]);
> + kfree(d);
> + return -ENOMEM;
> + }
> + }
> +
> + dst->pointer.str = (void *)d;
> + return 0;
> +}
> +
> static int property_entry_copy(struct property_entry *dst,
> const struct property_entry *src)
> {
> - const char **d, **s;
> - size_t i, nval;
> + int error;
>
> dst->name = kstrdup(src->name, GFP_KERNEL);
> if (!dst->name)
> return -ENOMEM;
>
> if (src->is_array) {
> - if (!src->length)
> - return -ENODATA;
> + if (!src->length) {
> + error = -ENODATA;
> + goto out_free_name;
> + }
>
> if (src->is_string) {
> - nval = src->length / sizeof(const char *);
> - dst->pointer.str = kcalloc(nval, sizeof(const char *),
> - GFP_KERNEL);
> - if (!dst->pointer.str)
> - return -ENOMEM;
> -
> - d = dst->pointer.str;
> - s = src->pointer.str;
> - for (i = 0; i < nval; i++) {
> - d[i] = kstrdup(s[i], GFP_KERNEL);
> - if (!d[i] && s[i])
> - return -ENOMEM;
> + error = property_copy_string_array(dst, src);
> + if (error) {
> + error = -ENOMEM;

An unnecessary set as the return from the above
property_copy_string_array is either 0 or -ENOMEM