staging:iio:tsl2563 rewrite probe error handling

tsl2563 probe function has two minor issues with it's error handling paths:
1) it is silent (did not report errors to dmesg)
2) did not return failure code (mixed up use of ret and err)

and two major issues:
3) goto fail2 would corrupt a free memory pool ("double free")
4) device registration failure did NOT cancel/flush delayed work.
   (and thus dereference a freed data structure later)

The "double free" is subtle and was introduced with this change:
    Author: Jonathan Cameron <jic23@cam.ac.uk>
    Date:   Mon Apr 18 12:58:55 2011 +0100
    staging:iio:tsl2563 take advantage of new iio_device_allocate private data.

Originally, chip was allocated seperately. Now it's appended to the
indio_dev by iio_allocate_device(sizeof(*chip)). So we only need one
kfree call as well (in iio_free_device()).

Gory details of tracking this down are here:
   http://crosbug.com/26819

Despite iio_device_registration failing, system can at least now boot.
Will follow up with a fix to "double register : in_intensity_both_raw"
error that is included in the bug report.

Signed-off-by: Grant Grundler <grundler@chromium.org>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Bryan Freed <bfreed@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/iio/light/tsl2563.c b/drivers/staging/iio/light/tsl2563.c
index aca1e03..546c95a 100644 (file)
--- a/drivers/staging/iio/light/tsl2563.c
+++ b/drivers/staging/iio/light/tsl2563.c
@@ -708,7 +708,6 @@ static int __devinit tsl2563_probe(struct i2c_client *client,
        struct tsl2563_chip *chip;
        struct tsl2563_platform_data *pdata = client->dev.platform_data;
        int err = 0;
-       int ret;
        u8 id = 0;
 
        indio_dev = iio_allocate_device(sizeof(*chip));
@@ -722,13 +721,15 @@ static int __devinit tsl2563_probe(struct i2c_client *client,
 
        err = tsl2563_detect(chip);
        if (err) {
-               dev_err(&client->dev, "device not found, error %d\n", -err);
+               dev_err(&client->dev, "detect error %d\n", -err);
                goto fail1;
        }
 
        err = tsl2563_read_id(chip, &id);
-       if (err)
+       if (err) {
+               dev_err(&client->dev, "read id error %d\n", -err);
                goto fail1;
+       }
 
        mutex_init(&chip->lock);
 
@@ -751,40 +752,52 @@ static int __devinit tsl2563_probe(struct i2c_client *client,
        indio_dev->num_channels = ARRAY_SIZE(tsl2563_channels);
        indio_dev->dev.parent = &client->dev;
        indio_dev->modes = INDIO_DIRECT_MODE;
+
        if (client->irq)
                indio_dev->info = &tsl2563_info;
        else
                indio_dev->info = &tsl2563_info_no_irq;
+
        if (client->irq) {
-               ret = request_threaded_irq(client->irq,
+               err = request_threaded_irq(client->irq,
                                           NULL,
                                           &tsl2563_event_handler,
                                           IRQF_TRIGGER_RISING | IRQF_ONESHOT,
                                           "tsl2563_event",
                                           indio_dev);
-               if (ret)
-                       goto fail2;
+               if (err) {
+                       dev_err(&client->dev, "irq request error %d\n", -err);
+                       goto fail1;
+               }
        }
+
        err = tsl2563_configure(chip);
-       if (err)
-               goto fail3;
+       if (err) {
+               dev_err(&client->dev, "configure error %d\n", -err);
+               goto fail2;
+       }
 
        INIT_DELAYED_WORK(&chip->poweroff_work, tsl2563_poweroff_work);
+
        /* The interrupt cannot yet be enabled so this is fine without lock */
        schedule_delayed_work(&chip->poweroff_work, 5 * HZ);
 
-       ret = iio_device_register(indio_dev);
-       if (ret)
+       err = iio_device_register(indio_dev);
+       if (err) {
+               dev_err(&client->dev, "iio registration error %d\n", -err);
                goto fail3;
+       }
 
        return 0;
+
 fail3:
+       cancel_delayed_work(&chip->poweroff_work);
+       flush_scheduled_work();
+fail2:
        if (client->irq)
                free_irq(client->irq, indio_dev);
-fail2:
-       iio_free_device(indio_dev);
 fail1:
-       kfree(chip);
+       iio_free_device(indio_dev);
        return err;
 }