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| author | Noralf Trønnes <noralf@tronnes.org> | 2021-10-18 13:37:31 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-14 10:16:57 +0100 |
| commit | 9be282312aba37785b47100f52c0d6a033d70a48 (patch) | |
| tree | b9ec392d2ff66e0fbbc98baa1f81727614e7fe8b /drivers | |
| parent | 18bb11826b1190ef332696e3dc2f0475c113749b (diff) | |
| download | linux-stable-9be282312aba37785b47100f52c0d6a033d70a48.tar.gz linux-stable-9be282312aba37785b47100f52c0d6a033d70a48.tar.bz2 linux-stable-9be282312aba37785b47100f52c0d6a033d70a48.zip | |
iio: dln2-adc: Fix lockdep complaint
commit 59f92868176f191eefde70d284bdfc1ed76a84bc upstream.
When reading the voltage:
$ cat /sys/bus/iio/devices/iio\:device0/in_voltage0_raw
Lockdep complains:
[ 153.910616] ======================================================
[ 153.916918] WARNING: possible circular locking dependency detected
[ 153.923221] 5.14.0+ #5 Not tainted
[ 153.926692] ------------------------------------------------------
[ 153.932992] cat/717 is trying to acquire lock:
[ 153.937525] c2585358 (&indio_dev->mlock){+.+.}-{3:3}, at: iio_device_claim_direct_mode+0x28/0x44
[ 153.946541]
but task is already holding lock:
[ 153.952487] c2585860 (&dln2->mutex){+.+.}-{3:3}, at: dln2_adc_read_raw+0x94/0x2bc [dln2_adc]
[ 153.961152]
which lock already depends on the new lock.
Fix this by not calling into the iio core underneath the dln2->mutex lock.
Fixes: 7c0299e879dd ("iio: adc: Add support for DLN2 ADC")
Cc: Jack Andersen <jackoalan@gmail.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://lore.kernel.org/r/20211018113731.25723-1-noralf@tronnes.org
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/adc/dln2-adc.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/drivers/iio/adc/dln2-adc.c b/drivers/iio/adc/dln2-adc.c index 2a299bbd6acf..d43af161f275 100644 --- a/drivers/iio/adc/dln2-adc.c +++ b/drivers/iio/adc/dln2-adc.c @@ -251,7 +251,6 @@ static int dln2_adc_set_chan_period(struct dln2_adc *dln2, static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel) { int ret, i; - struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev); u16 conflict; __le16 value; int olen = sizeof(value); @@ -260,13 +259,9 @@ static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel) .chan = channel, }; - ret = iio_device_claim_direct_mode(indio_dev); - if (ret < 0) - return ret; - ret = dln2_adc_set_chan_enabled(dln2, channel, true); if (ret < 0) - goto release_direct; + return ret; ret = dln2_adc_set_port_enabled(dln2, true, &conflict); if (ret < 0) { @@ -303,8 +298,6 @@ disable_port: dln2_adc_set_port_enabled(dln2, false, NULL); disable_chan: dln2_adc_set_chan_enabled(dln2, channel, false); -release_direct: - iio_device_release_direct_mode(indio_dev); return ret; } @@ -340,10 +333,16 @@ static int dln2_adc_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret < 0) + return ret; + mutex_lock(&dln2->mutex); ret = dln2_adc_read(dln2, chan->channel); mutex_unlock(&dln2->mutex); + iio_device_release_direct_mode(indio_dev); + if (ret < 0) return ret; |