On Wed, 2023-08-23 at 19:26 +0300, Andy Shevchenko wrote:
> On Wed, Aug 23, 2023 at 05:58:06PM +0200, Angel Iglesias wrote:
> > Improve device detection in certain chip families known to have various
> > chip ids.
>
> IDs
>
> ...
>
> > #include <linux/completion.h>
> > #include <linux/pm_runtime.h>
> > #include <linux/random.h>
> > +#include <linux/overflow.h>
>
> Please, preserve ordering.
>
> ...
>
> > struct bmp280_data *data;
> > struct gpio_desc *gpiod;
> > unsigned int chip_id;
> > - int ret;
> > + int ret, i;
>
> unsigned int i;
>
> ...
>
> > + if (i == data->chip_info->num_chip_id) {
> > + size_t nbuf;
> > + char *buf;
> > +
> > + // 0x<id>, so four chars per number plus one space + ENDL
>
> > + if (check_mul_overflow(5, data->chip_info->num_chip_id,
> > &nbuf))
> > + return ret;
> > +
> > + buf = kmalloc_array(nbuf, sizeof(char), GFP_KERNEL);
>
> We almost never do a array allocation for byte sizes. Instead of the above you
> need to use
>
> buf = kmalloc_array(data->chip_info->num_chip_id, 5,
> GFP_KERNEL);
>
> > + if (!buf)
>
> This check assumes that num_chip_id is never 0, so...
>
> > + return ret;
> > +
> > + for (i = 0; i < data->chip_info->num_chip_id; i++)
> > + snprintf(&buf[i*5], nbuf, "0x%x ", data->chip_info-
> > >chip_id[i]);
>
> > + buf[nbuf-1] = '\0';
>
> ...this is redundant assignment. sprintf() guarantees the NUL termination.
>
> > +
> > + dev_err(dev, "bad chip id: expected [ %s ] got 0x%x\n", buf,
> > chip_id);
>
> "...expected one of..."
>
> > + kfree(buf);
> > + return ret;
>
> Oh, I didn't get that you allocated memory only to print a message...
Yes, I just wanted to print the known IDs like before in a readable manner. If
it is overkill, I'll change it for a more generic error message.
>
> > }
>
Kind regards,
Angel
