Re: [usb:usb-testing 63/64] drivers/usb/typec/mux.c:167 typec_mux_match() warn: unsigned 'nval' is never less than zero.

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On Fri, Feb 15, 2019 at 11:01 AM Heikki Krogerus
<heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
>
> On Fri, Feb 15, 2019 at 01:33:24PM +0800, kbuild test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> > head:   09aa11cfda9d8186046bcd1adcd6498b688114f4
> > commit: 96a6d031ca9930938bd66d0052fc7ed2b56e3583 [63/64] usb: typec: mux: Find the muxes by also matching against the device node
> >
> > smatch warnings:
> > drivers/usb/typec/mux.c:167 typec_mux_match() warn: unsigned 'nval' is never less than zero.
>
> I'm assuming this means we should not use type 'size_t' in this case.
>
> I'll send a patch where I'll use 'int' instead if 'size_t'.

Perhaps, in case of < 0 it should return it as error pointer to the caller?

>
> > vim +/nval +167 drivers/usb/typec/mux.c
> >
> >    124
> >    125        static void *typec_mux_match(struct device_connection *con, int ep, void *data)
> >    126        {
> >    127                const struct typec_altmode_desc *desc = data;
> >    128                struct typec_mux *mux;
> >    129                size_t nval;
> >    130                bool match;
> >    131                u16 *val;
> >    132                int i;
> >    133
> >    134                if (!con->fwnode) {
> >    135                        list_for_each_entry(mux, &mux_list, entry)
> >    136                                if (!strcmp(con->endpoint[ep], dev_name(mux->dev)))
> >    137                                        return mux;
> >    138                        return ERR_PTR(-EPROBE_DEFER);
> >    139                }
> >    140
> >    141                /*
> >    142                 * Check has the identifier already been "consumed". If it
> >    143                 * has, no need to do any extra connection identification.
> >    144                 */
> >    145                match = !con->id;
> >    146                if (match)
> >    147                        goto find_mux;
> >    148
> >    149                /* Accessory Mode muxes */
> >    150                if (!desc) {
> >    151                        match = fwnode_property_present(con->fwnode, "accessory");
> >    152                        if (match)
> >    153                                goto find_mux;
> >    154                        return NULL;
> >    155                }
> >    156
> >    157                /* Alternate Mode muxes */
> >    158                nval = fwnode_property_read_u16_array(con->fwnode, "svid", NULL, 0);
> >    159                if (nval <= 0)
> >    160                        return NULL;
> >    161
> >    162                val = kcalloc(nval, sizeof(*val), GFP_KERNEL);
> >    163                if (!val)
> >    164                        return ERR_PTR(-ENOMEM);
> >    165
> >    166                nval = fwnode_property_read_u16_array(con->fwnode, "svid", val, nval);
> >  > 167                if (nval < 0) {
> >    168                        kfree(val);
> >    169                        return ERR_PTR(nval);
> >    170                }
> >    171
> >    172                for (i = 0; i < nval; i++) {
> >    173                        match = val[i] == desc->svid;
> >    174                        if (match) {
> >    175                                kfree(val);
> >    176                                goto find_mux;
> >    177                        }
> >    178                }
> >    179                kfree(val);
> >    180                return NULL;
> >    181
> >    182        find_mux:
> >    183                list_for_each_entry(mux, &mux_list, entry)
> >    184                        if (dev_fwnode(mux->dev) == con->fwnode)
> >    185                                return mux;
> >    186
> >    187                return match ? ERR_PTR(-EPROBE_DEFER) : NULL;
> >    188        }
> >    189
>
> thanks,
>
> --
> heikki



-- 
With Best Regards,
Andy Shevchenko



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