[PATCH 6.1 0723/1146] iio: adis: add __adis_enable_irq() implementation

Greg Kroah-Hartman
2022-12-28T16:25:14Z

From: Ramona Bolboaca <ramona.bolboaca@analog.com>

[ Upstream commit 99c05e4283a19a02a256f14100ca4ec3b2da3f62 ]

Add '__adis_enable_irq()' implementation which is the unlocked
version of 'adis_enable_irq()'.
Call '__adis_enable_irq()' instead of 'adis_enable_irq()' from
'__adis_intial_startup()' to keep the expected unlocked functionality.

This fix is needed to remove a deadlock for all devices which are
using 'adis_initial_startup()'. The deadlock occurs because the
same mutex is acquired twice, without releasing it.
The mutex is acquired once inside 'adis_initial_startup()', before
calling '__adis_initial_startup()', and once inside
'adis_enable_irq()', which is called by '__adis_initial_startup()'.
The deadlock is removed by calling '__adis_enable_irq()', instead of
'adis_enable_irq()' from within '__adis_initial_startup()'.

Fixes: b600bd7eb3335 ("iio: adis: do not disabe IRQs in 'adis_init()'")
Signed-off-by: Ramona Bolboaca <ramona.bolboaca@analog.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20221122082757.449452-2-ramona.bolboaca@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/imu/adis.c | 28 ++++++++++------------------
include/linux/iio/imu/adis.h | 13 ++++++++++++-
2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index f7fcfd04f659..bc40240b29e2 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -270,23 +270,19 @@ EXPORT_SYMBOL_NS(adis_debugfs_reg_access, IIO_ADISLIB);
#endif

/**
- * adis_enable_irq() - Enable or disable data ready IRQ
+ * __adis_enable_irq() - Enable or disable data ready IRQ (unlocked)
* @adis: The adis device
* @enable: Whether to enable the IRQ
*
* Returns 0 on success, negative error code otherwise
*/
-int adis_enable_irq(struct adis *adis, bool enable)
+int __adis_enable_irq(struct adis *adis, bool enable)
{
- int ret = 0;
+ int ret;
u16 msc;

- mutex_lock(&adis->state_lock);
-
- if (adis->data->enable_irq) {
- ret = adis->data->enable_irq(adis, enable);
- goto out_unlock;
- }
+ if (adis->data->enable_irq)
+ return adis->data->enable_irq(adis, enable);

if (adis->data->unmasked_drdy) {
if (enable)
@@ -294,12 +290,12 @@ int adis_enable_irq(struct adis *adis, bool enable)
else
disable_irq(adis->spi->irq);

- goto out_unlock;
+ return 0;
}

ret = __adis_read_reg_16(adis, adis->data->msc_ctrl_reg, &msc);
if (ret)
- goto out_unlock;
+ return ret;

msc |= ADIS_MSC_CTRL_DATA_RDY_POL_HIGH;
msc &= ~ADIS_MSC_CTRL_DATA_RDY_DIO2;
@@ -308,13 +304,9 @@ int adis_enable_irq(struct adis *adis, bool enable)
else
msc &= ~ADIS_MSC_CTRL_DATA_RDY_EN;

- ret = __adis_write_reg_16(adis, adis->data->msc_ctrl_reg, msc);
-
-out_unlock:
- mutex_unlock(&adis->state_lock);
- return ret;
+ return __adis_write_reg_16(adis, adis->data->msc_ctrl_reg, msc);
}
-EXPORT_SYMBOL_NS(adis_enable_irq, IIO_ADISLIB);
+EXPORT_SYMBOL_NS(__adis_enable_irq, IIO_ADISLIB);

/**
* __adis_check_status() - Check the device for error conditions (unlocked)
@@ -445,7 +437,7 @@ int __adis_initial_startup(struct adis *adis)
* with 'IRQF_NO_AUTOEN' anyways.
*/
if (!adis->data->unmasked_drdy)
- adis_enable_irq(adis, false);
+ __adis_enable_irq(adis, false);

if (!adis->data->prod_id_reg)
return 0;
diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
index 515ca09764fe..bcbefb757475 100644
--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -402,9 +402,20 @@ static inline int adis_update_bits_base(struct adis *adis, unsigned int reg,
__adis_update_bits_base(adis, reg, mask, val, sizeof(val)); \
})

-int adis_enable_irq(struct adis *adis, bool enable);
int __adis_check_status(struct adis *adis);
int __adis_initial_startup(struct adis *adis);
+int __adis_enable_irq(struct adis *adis, bool enable);
+
+static inline int adis_enable_irq(struct adis *adis, bool enable)
+{
+ int ret;
+
+ mutex_lock(&adis->state_lock);
+ ret = __adis_enable_irq(adis, enable);
+ mutex_unlock(&adis->state_lock);
+
+ return ret;
+}

static inline int adis_check_status(struct adis *adis)
{
--
2.35.1