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staging: iio: ad5933: avoid uninitialized variable in error case 

The ad5933_i2c_read function returns an error code to indicate
whether it could read data or not. However ad5933_work() ignores
this return code and just accesses the data unconditionally,
which gets detected by gcc as a possible bug:

drivers/staging/iio/impedance-analyzer/ad5933.c: In function 'ad5933_work':
drivers/staging/iio/impedance-analyzer/ad5933.c:649:16: warning: 'status' may be used uninitialized in this function [-Wmaybe-uninitialized]

This adds minimal error handling so we only evaluate the
data if it was correctly read.

Link: https://patchwork.kernel.org/patch/8110281/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Arnd Bergmann 2016-10-24 17:22:01 +02:00 committed by Jonathan Cameron
parent e866dd8aab
commit 34eee70a7b
1 changed files with 10 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/staging/iio/impedance-analyzer/ad5933.c
View File

@ -655,6 +655,7 @@ static void ad5933_work(struct work_struct *work)
__be16 buf[2];
int val[2];
unsigned char status;
int ret;
mutex_lock(&indio_dev->mlock);
if (st->state == AD5933_CTRL_INIT_START_FREQ) {
@ -662,19 +663,22 @@ static void ad5933_work(struct work_struct *work)
ad5933_cmd(st, AD5933_CTRL_START_SWEEP);
st->state = AD5933_CTRL_START_SWEEP;
schedule_delayed_work(&st->work, st->poll_time_jiffies);
mutex_unlock(&indio_dev->mlock);
return;
goto out;
}
ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);
ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);
if (ret)
goto out;
if (status & AD5933_STAT_DATA_VALID) {
int scan_count = bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength);
ad5933_i2c_read(st->client,
ret = ad5933_i2c_read(st->client,
test_bit(1, indio_dev->active_scan_mask) ?
AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,
scan_count * 2, (u8 *)buf);
if (ret)
goto out;
if (scan_count == 2) {
val[0] = be16_to_cpu(buf[0]);
@ -686,8 +690,7 @@ static void ad5933_work(struct work_struct *work)
} else {
/* no data available - try again later */
schedule_delayed_work(&st->work, st->poll_time_jiffies);
mutex_unlock(&indio_dev->mlock);
return;
goto out;
}
if (status & AD5933_STAT_SWEEP_DONE) {
@ -700,7 +703,7 @@ static void ad5933_work(struct work_struct *work)
ad5933_cmd(st, AD5933_CTRL_INC_FREQ);
schedule_delayed_work(&st->work, st->poll_time_jiffies);
}
out:
mutex_unlock(&indio_dev->mlock);
}