2021-12-27 09:46:00

by Uwe Kleine-König

[permalink] [raw]
Subject: [PATCH v2 15/23] counter: 104-quad-8: Convert to new counter registration

This fixes device lifetime issues where it was possible to free a live
struct device.

Fixes: f1d8a071d45b ("counter: 104-quad-8: Add Generic Counter interface support")
Signed-off-by: Uwe Kleine-König <[email protected]>
---
drivers/counter/104-quad-8.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 6e5286cd1d4e..4315b14f239e 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -52,7 +52,6 @@ MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
*/
struct quad8 {
spinlock_t lock;
- struct counter_device counter;
unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
unsigned int preset[QUAD8_NUM_COUNTERS];
unsigned int count_mode[QUAD8_NUM_COUNTERS];
@@ -1127,6 +1126,7 @@ static irqreturn_t quad8_irq_handler(int irq, void *private)

static int quad8_probe(struct device *dev, unsigned int id)
{
+ struct counter_device *counter;
struct quad8 *priv;
int i, j;
unsigned int base_offset;
@@ -1138,19 +1138,19 @@ static int quad8_probe(struct device *dev, unsigned int id)
return -EBUSY;
}

- priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
- if (!priv)
+ counter = devm_counter_alloc(dev, sizeof(*priv));
+ if (!counter)
return -ENOMEM;
+ priv = counter_priv(counter);

/* Initialize Counter device and driver data */
- priv->counter.name = dev_name(dev);
- priv->counter.parent = dev;
- priv->counter.ops = &quad8_ops;
- priv->counter.counts = quad8_counts;
- priv->counter.num_counts = ARRAY_SIZE(quad8_counts);
- priv->counter.signals = quad8_signals;
- priv->counter.num_signals = ARRAY_SIZE(quad8_signals);
- priv->counter.priv = priv;
+ counter->name = dev_name(dev);
+ counter->parent = dev;
+ counter->ops = &quad8_ops;
+ counter->counts = quad8_counts;
+ counter->num_counts = ARRAY_SIZE(quad8_counts);
+ counter->signals = quad8_signals;
+ counter->num_signals = ARRAY_SIZE(quad8_signals);
priv->base = base[id];

spin_lock_init(&priv->lock);
@@ -1192,11 +1192,15 @@ static int quad8_probe(struct device *dev, unsigned int id)
outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);

err = devm_request_irq(dev, irq[id], quad8_irq_handler, IRQF_SHARED,
- priv->counter.name, priv);
+ counter->name, priv);
if (err)
return err;

- return devm_counter_register(dev, &priv->counter);
+ err = devm_counter_add(dev, counter);
+ if (err < 0)
+ return dev_err_probe(dev, err, "Failed to add counter\n");
+
+ return 0;
}

static struct isa_driver quad8_driver = {
--
2.33.0



2021-12-27 12:19:32

by Lars-Peter Clausen

[permalink] [raw]
Subject: Re: [PATCH v2 15/23] counter: 104-quad-8: Convert to new counter registration

On 12/27/21 10:45 AM, Uwe Kleine-König wrote:
> [...]
>
> - return devm_counter_register(dev, &priv->counter);
> + err = devm_counter_add(dev, counter);
> + if (err < 0)
> + return dev_err_probe(dev, err, "Failed to add counter\n");
I wonder if we should put that dev_err_probe into the devm_counter_add
since every driver wants to have it anyway.
> +
> + return 0;
> }
>
> static struct isa_driver quad8_driver = {



2021-12-28 11:06:30

by Uwe Kleine-König

[permalink] [raw]
Subject: Re: [PATCH v2 15/23] counter: 104-quad-8: Convert to new counter registration

On Mon, Dec 27, 2021 at 01:19:25PM +0100, Lars-Peter Clausen wrote:
> On 12/27/21 10:45 AM, Uwe Kleine-K?nig wrote:
> > [...]
> > - return devm_counter_register(dev, &priv->counter);
> > + err = devm_counter_add(dev, counter);
> > + if (err < 0)
> > + return dev_err_probe(dev, err, "Failed to add counter\n");
> I wonder if we should put that dev_err_probe into the devm_counter_add since
> every driver wants to have it anyway.

Personally I'm not a big fan of API functions that emit an error
message. Usually the consumer knows best if a certain failing function
call is worth an error message. Look at platform_get_irq() that some
time ago got a dev_err call. The result was to introduce a
silent variant (platform_get_irq_optional()) because emitting an error
message isn't the right thing in all cases.

Also the API function probably won't call
device_set_deferred_probe_reason() and so the consumer has to care for
that anyhow (or not which makes -EPROBE_DEFER problems harder to debug).

Furthermore the consumer can emit in some cases a better error message
than the core. (Well, this doesn't apply here, but in the example of
platform_get_irq() the driver knows the irq's purpose and can call it
"TX irq" in the error message which the irq core cannot.)

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | https://www.pengutronix.de/ |


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2021-12-28 18:11:58

by Jonathan Cameron

[permalink] [raw]
Subject: Re: [PATCH v2 15/23] counter: 104-quad-8: Convert to new counter registration

On Mon, 27 Dec 2021 10:45:18 +0100
Uwe Kleine-König <[email protected]> wrote:

> This fixes device lifetime issues where it was possible to free a live
> struct device.
>
> Fixes: f1d8a071d45b ("counter: 104-quad-8: Add Generic Counter interface support")
> Signed-off-by: Uwe Kleine-König <[email protected]>
LGTM

Reviewed-by: Jonathan Cameron <[email protected]>
> ---
> drivers/counter/104-quad-8.c | 30 +++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 6e5286cd1d4e..4315b14f239e 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -52,7 +52,6 @@ MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
> */
> struct quad8 {
> spinlock_t lock;
> - struct counter_device counter;
> unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
> unsigned int preset[QUAD8_NUM_COUNTERS];
> unsigned int count_mode[QUAD8_NUM_COUNTERS];
> @@ -1127,6 +1126,7 @@ static irqreturn_t quad8_irq_handler(int irq, void *private)
>
> static int quad8_probe(struct device *dev, unsigned int id)
> {
> + struct counter_device *counter;
> struct quad8 *priv;
> int i, j;
> unsigned int base_offset;
> @@ -1138,19 +1138,19 @@ static int quad8_probe(struct device *dev, unsigned int id)
> return -EBUSY;
> }
>
> - priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> - if (!priv)
> + counter = devm_counter_alloc(dev, sizeof(*priv));
> + if (!counter)
> return -ENOMEM;
> + priv = counter_priv(counter);
>
> /* Initialize Counter device and driver data */
> - priv->counter.name = dev_name(dev);
> - priv->counter.parent = dev;
> - priv->counter.ops = &quad8_ops;
> - priv->counter.counts = quad8_counts;
> - priv->counter.num_counts = ARRAY_SIZE(quad8_counts);
> - priv->counter.signals = quad8_signals;
> - priv->counter.num_signals = ARRAY_SIZE(quad8_signals);
> - priv->counter.priv = priv;
> + counter->name = dev_name(dev);
> + counter->parent = dev;
> + counter->ops = &quad8_ops;
> + counter->counts = quad8_counts;
> + counter->num_counts = ARRAY_SIZE(quad8_counts);
> + counter->signals = quad8_signals;
> + counter->num_signals = ARRAY_SIZE(quad8_signals);
> priv->base = base[id];
>
> spin_lock_init(&priv->lock);
> @@ -1192,11 +1192,15 @@ static int quad8_probe(struct device *dev, unsigned int id)
> outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);
>
> err = devm_request_irq(dev, irq[id], quad8_irq_handler, IRQF_SHARED,
> - priv->counter.name, priv);
> + counter->name, priv);
> if (err)
> return err;
>
> - return devm_counter_register(dev, &priv->counter);
> + err = devm_counter_add(dev, counter);
> + if (err < 0)
> + return dev_err_probe(dev, err, "Failed to add counter\n");
> +
> + return 0;
> }
>
> static struct isa_driver quad8_driver = {


2021-12-29 08:25:10

by William Breathitt Gray

[permalink] [raw]
Subject: Re: [PATCH v2 15/23] counter: 104-quad-8: Convert to new counter registration

On Mon, Dec 27, 2021 at 10:45:18AM +0100, Uwe Kleine-König wrote:
> This fixes device lifetime issues where it was possible to free a live
> struct device.
>
> Fixes: f1d8a071d45b ("counter: 104-quad-8: Add Generic Counter interface support")
> Signed-off-by: Uwe Kleine-König <[email protected]>

Acked-by: William Breathitt Gray <[email protected]>

> ---
> drivers/counter/104-quad-8.c | 30 +++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 6e5286cd1d4e..4315b14f239e 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -52,7 +52,6 @@ MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
> */
> struct quad8 {
> spinlock_t lock;
> - struct counter_device counter;
> unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
> unsigned int preset[QUAD8_NUM_COUNTERS];
> unsigned int count_mode[QUAD8_NUM_COUNTERS];
> @@ -1127,6 +1126,7 @@ static irqreturn_t quad8_irq_handler(int irq, void *private)
>
> static int quad8_probe(struct device *dev, unsigned int id)
> {
> + struct counter_device *counter;
> struct quad8 *priv;
> int i, j;
> unsigned int base_offset;
> @@ -1138,19 +1138,19 @@ static int quad8_probe(struct device *dev, unsigned int id)
> return -EBUSY;
> }
>
> - priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> - if (!priv)
> + counter = devm_counter_alloc(dev, sizeof(*priv));
> + if (!counter)
> return -ENOMEM;
> + priv = counter_priv(counter);
>
> /* Initialize Counter device and driver data */
> - priv->counter.name = dev_name(dev);
> - priv->counter.parent = dev;
> - priv->counter.ops = &quad8_ops;
> - priv->counter.counts = quad8_counts;
> - priv->counter.num_counts = ARRAY_SIZE(quad8_counts);
> - priv->counter.signals = quad8_signals;
> - priv->counter.num_signals = ARRAY_SIZE(quad8_signals);
> - priv->counter.priv = priv;
> + counter->name = dev_name(dev);
> + counter->parent = dev;
> + counter->ops = &quad8_ops;
> + counter->counts = quad8_counts;
> + counter->num_counts = ARRAY_SIZE(quad8_counts);
> + counter->signals = quad8_signals;
> + counter->num_signals = ARRAY_SIZE(quad8_signals);
> priv->base = base[id];
>
> spin_lock_init(&priv->lock);
> @@ -1192,11 +1192,15 @@ static int quad8_probe(struct device *dev, unsigned int id)
> outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);
>
> err = devm_request_irq(dev, irq[id], quad8_irq_handler, IRQF_SHARED,
> - priv->counter.name, priv);
> + counter->name, priv);
> if (err)
> return err;
>
> - return devm_counter_register(dev, &priv->counter);
> + err = devm_counter_add(dev, counter);
> + if (err < 0)
> + return dev_err_probe(dev, err, "Failed to add counter\n");
> +
> + return 0;
> }
>
> static struct isa_driver quad8_driver = {
> --
> 2.33.0
>


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