Messages in this thread | | | Date | Wed, 29 Nov 2023 16:57:22 +0200 | From | Andy Shevchenko <> | Subject | Re: [PATCH 01/10] gpiolib: provide gpiochip_dup_line_label() |
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On Wed, Nov 29, 2023 at 03:24:02PM +0100, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> > > gpiochip_is_requested() not only has a misleading name but it returns > a pointer to a string that is freed when the descriptor is released. > > Provide a new helper meant to replace it, which returns a copy of the > label string instead.
...
> +/** > + * gpiochip_dup_line_label - Get a copy of the consumer label. > + * @gc: GPIO chip controlling this line. > + * @offset: Hardware offset of the line. > + * > + * Returns: > + * Pointer to a copy of the consumer label if the line is requested or NULL > + * if it's not. If a valid pointer was returned, it must be freed using > + * kfree(). In case of a memory allocation error, the function returns %ENOMEM.
kfree_const() ? (see below)
> + * Must not be called from atomic context. > + */ > +char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset) > +{ > + const char *label; > + char *cpy;
Why not "copy"?
> + > + label = gpiochip_is_requested(gc, offset); > + if (!label) > + return NULL;
> + cpy = kstrdup(label, GFP_KERNEL);
You probably want to have kstrdup_const(). However, I haven't checked if we have such use cases.
> + if (!cpy) > + return ERR_PTR(-ENOMEM); > + > + return cpy; > +}
So, how does this differ from the previous one? You need to hold a reference to the descriptor before copying and release it after.
-- With Best Regards, Andy Shevchenko
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