Messages in this thread | | | Date | Fri, 14 Sep 2012 09:24:03 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH 2/2] iio: inkern: add error case in iio_channel_get() |
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On 14/09/12 01:59, Kim, Milo wrote: >> On 10/09/12 09:02, Kim, Milo wrote: >>> The datasheet name is defined in the IIO driver. >>> On the other hand, the adc_channel_label is configured in >>> the platform machine side. >>> If the datasheet name is not matched with any adc_channel_label, >>> the iio_channel_get() should be returned as error for preventing >>> using invalid IIO channel data. >>> >>> Moreover, this patch detects NULL pointer dereference problem at >> early time. >>> In general, the IIO driver just accesses to any member of the >> iio_chan_spec >>> in own xxx_read_raw() function. >>> If the iio_chan_spec is invalid pointer, NULL dereference problem >> may occur >>> such like 'iio_chan_spec->channel' or 'iio_chan_spec->type'. >>> If the iio_channel_get() gets failed in the IIO consumer, >>> then no read_raw() operation proceeds. > >> I guess this is marginally cleaner, but either way it is up to the >> calling driver to check whether the call succeeded. > > IMO, it would be better if iio_channel_get() gets failed > when the consumer tries to get the channel rather than when using it. > > The channel spec is retrieved when the channel is requested, - iio_channel_get() > So it's reasonable if error returns in case of invalid channel spcec. > > And I just found similar handling in iio_channel_get_all(). > But my patch needs releasing the memory as Lars-Peter noted. Fine, I'm convinced. Certainly less weird doing it your way ;) Please do fix up the get all case as well. > > Thanks ! > > Best Regards, > Milo > >>> >>> Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com> >>> --- >>> drivers/iio/inkern.c | 6 +++++- >>> 1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c >>> index 1faa240..a5caf6b 100644 >>> --- a/drivers/iio/inkern.c >>> +++ b/drivers/iio/inkern.c >>> @@ -136,11 +136,15 @@ struct iio_channel *iio_channel_get(const char >> *name, const char *channel_name) >>> >>> channel->indio_dev = c->indio_dev; >>> >>> - if (c->map->adc_channel_label) >>> + if (c->map->adc_channel_label) { >>> channel->channel = >>> iio_chan_spec_from_name(channel->indio_dev, >>> c->map->adc_channel_label); >>> >>> + if (channel->channel == NULL) >>> + return ERR_PTR(-ENODEV); >>> + } >>> + >>> return channel; >>> } >>> EXPORT_SYMBOL_GPL(iio_channel_get); >>> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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