On Mon, Jun 29, 2020 at 2:22 PM Andrzej Hajda <[email protected]> wrote:
>
> During probe every time driver gets resource it should usually check for
> error printk some message if it is not -EPROBE_DEFER and return the error.
> This pattern is simple but requires adding few lines after any resource
> acquisition code, as a result it is often omitted or implemented only
> partially.
> dev_err_probe helps to replace such code sequences with simple call,
> so code:
> if (err != -EPROBE_DEFER)
> dev_err(dev, ...);
> return err;
> becomes:
> return dev_err_probe(dev, err, ...);
FWIW,
Reviewed-by: Andy Shevchenko <[email protected]>
(I'm fine with current code, though, consider below comments)
> Signed-off-by: Andrzej Hajda <[email protected]>
> Reviewed-by: Rafael J. Wysocki <[email protected]>
> ---
> drivers/base/core.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/device.h | 3 +++
> 2 files changed, 45 insertions(+)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 67d39a90b45c..3a827c82933f 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -3953,6 +3953,48 @@ define_dev_printk_level(_dev_info, KERN_INFO);
>
> #endif
>
> +/**
> + * dev_err_probe - probe error check and log helper
> + * @dev: the pointer to the struct device
> + * @err: error value to test
> + * @fmt: printf-style format string
> + * @...: arguments as specified in the format string
> + *
> + * This helper implements common pattern present in probe functions for error
> + * checking: print debug or error message depending if the error value is
> + * -EPROBE_DEFER and propagate error upwards.
> + * It replaces code sequence:
> + * if (err != -EPROBE_DEFER)
> + * dev_err(dev, ...);
> + * else
> + * dev_dbg(dev, ...);
> + * return err;
> + * with
> + * return dev_err_probe(dev, err, ...);
> + *
> + * Returns @err.
> + *
> + */
> +int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
> +{
> + struct va_format vaf;
> + va_list args;
> +
> + va_start(args, fmt);
> + vaf.fmt = fmt;
> + vaf.va = &args;
> +
> + if (err != -EPROBE_DEFER)
Perhaps positive conditional.
> + dev_err(dev, "error %d: %pV", err, &vaf);
> + else
> + dev_dbg(dev, "error %d: %pV", err, &vaf);
Perhaps {} to be added here.
> +
> + va_end(args);
> +
> + return err;
> +}
> +EXPORT_SYMBOL_GPL(dev_err_probe);
> +
> static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
> {
> return fwnode && !IS_ERR(fwnode->secondary);
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 15460a5ac024..6b2272ae9af8 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -964,6 +964,9 @@ void device_link_remove(void *consumer, struct device *supplier);
> void device_links_supplier_sync_state_pause(void);
> void device_links_supplier_sync_state_resume(void);
>
> +extern __printf(3, 4)
> +int dev_err_probe(const struct device *dev, int err, const char *fmt, ...);
> +
> /* Create alias, so I can be autoloaded. */
> #define MODULE_ALIAS_CHARDEV(major,minor) \
> MODULE_ALIAS("char-major-" __stringify(major) "-" __stringify(minor))
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
/sys/kernel/debug/devices_deferred property contains list of deferred devices.
This list does not contain reason why the driver deferred probe, the patch
improves it.
The natural place to set the reason is dev_err_probe function introduced
recently, ie. if dev_err_probe will be called with -EPROBE_DEFER instead of
printk the message will be attached to a deferred device and printed when user
reads devices_deferred property.
Signed-off-by: Andrzej Hajda <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Reviewed-by: Javier Martinez Canillas <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Rafael J. Wysocki <[email protected]>
---
v8:
- improved commit message
---
drivers/base/base.h | 3 +++
drivers/base/core.c | 8 ++++++--
drivers/base/dd.c | 23 ++++++++++++++++++++++-
3 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/drivers/base/base.h b/drivers/base/base.h
index 95c22c0f9036..6954fccab3d7 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -93,6 +93,7 @@ struct device_private {
struct klist_node knode_class;
struct list_head deferred_probe;
struct device_driver *async_driver;
+ char *deferred_probe_reason;
struct device *device;
u8 dead:1;
};
@@ -134,6 +135,8 @@ extern void device_release_driver_internal(struct device *dev,
extern void driver_detach(struct device_driver *drv);
extern int driver_probe_device(struct device_driver *drv, struct device *dev);
extern void driver_deferred_probe_del(struct device *dev);
+extern void device_set_deferred_probe_reson(const struct device *dev,
+ struct va_format *vaf);
static inline int driver_match_device(struct device_driver *drv,
struct device *dev)
{
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 3a827c82933f..fee047f03681 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3963,6 +3963,8 @@ define_dev_printk_level(_dev_info, KERN_INFO);
* This helper implements common pattern present in probe functions for error
* checking: print debug or error message depending if the error value is
* -EPROBE_DEFER and propagate error upwards.
+ * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
+ * checked later by reading devices_deferred debugfs attribute.
* It replaces code sequence:
* if (err != -EPROBE_DEFER)
* dev_err(dev, ...);
@@ -3984,10 +3986,12 @@ int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
vaf.fmt = fmt;
vaf.va = &args;
- if (err != -EPROBE_DEFER)
+ if (err != -EPROBE_DEFER) {
dev_err(dev, "error %d: %pV", err, &vaf);
- else
+ } else {
+ device_set_deferred_probe_reson(dev, &vaf);
dev_dbg(dev, "error %d: %pV", err, &vaf);
+ }
va_end(args);
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 9a1d940342ac..dd5683b61f74 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -27,6 +27,7 @@
#include <linux/async.h>
#include <linux/pm_runtime.h>
#include <linux/pinctrl/devinfo.h>
+#include <linux/slab.h>
#include "base.h"
#include "power/power.h"
@@ -136,6 +137,8 @@ void driver_deferred_probe_del(struct device *dev)
if (!list_empty(&dev->p->deferred_probe)) {
dev_dbg(dev, "Removed from deferred list\n");
list_del_init(&dev->p->deferred_probe);
+ kfree(dev->p->deferred_probe_reason);
+ dev->p->deferred_probe_reason = NULL;
}
mutex_unlock(&deferred_probe_mutex);
}
@@ -211,6 +214,23 @@ void device_unblock_probing(void)
driver_deferred_probe_trigger();
}
+/**
+ * device_set_deferred_probe_reson() - Set defer probe reason message for device
+ * @dev: the pointer to the struct device
+ * @vaf: the pointer to va_format structure with message
+ */
+void device_set_deferred_probe_reson(const struct device *dev, struct va_format *vaf)
+{
+ const char *drv = dev_driver_string(dev);
+
+ mutex_lock(&deferred_probe_mutex);
+
+ kfree(dev->p->deferred_probe_reason);
+ dev->p->deferred_probe_reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
+
+ mutex_unlock(&deferred_probe_mutex);
+}
+
/*
* deferred_devs_show() - Show the devices in the deferred probe pending list.
*/
@@ -221,7 +241,8 @@ static int deferred_devs_show(struct seq_file *s, void *data)
mutex_lock(&deferred_probe_mutex);
list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
- seq_printf(s, "%s\n", dev_name(curr->device));
+ seq_printf(s, "%s\t%s", dev_name(curr->device),
+ curr->device->p->deferred_probe_reason ?: "\n");
mutex_unlock(&deferred_probe_mutex);
--
2.17.1
On Thu, Jul 02, 2020 at 03:44:21PM +0200, Andrzej Hajda wrote:
> /sys/kernel/debug/devices_deferred property contains list of deferred devices.
> This list does not contain reason why the driver deferred probe, the patch
> improves it.
> The natural place to set the reason is dev_err_probe function introduced
> recently, ie. if dev_err_probe will be called with -EPROBE_DEFER instead of
> printk the message will be attached to a deferred device and printed when user
> reads devices_deferred property.
>
> Signed-off-by: Andrzej Hajda <[email protected]>
> Reviewed-by: Mark Brown <[email protected]>
> Reviewed-by: Javier Martinez Canillas <[email protected]>
> Reviewed-by: Andy Shevchenko <[email protected]>
> Reviewed-by: Rafael J. Wysocki <[email protected]>
> ---
> v8:
> - improved commit message
I'm totally confused by this series. Can you resend the whole thing,
as a full series, not just random individual patches in the series
incremented? It's a pain to try to fish them all out as to which is the
"latest" with all of the needed reviewed by lines :(
thanks,
greg k-h
On 10.07.2020 15:31, Greg Kroah-Hartman wrote:
> On Thu, Jul 02, 2020 at 03:44:21PM +0200, Andrzej Hajda wrote:
>> /sys/kernel/debug/devices_deferred property contains list of deferred devices.
>> This list does not contain reason why the driver deferred probe, the patch
>> improves it.
>> The natural place to set the reason is dev_err_probe function introduced
>> recently, ie. if dev_err_probe will be called with -EPROBE_DEFER instead of
>> printk the message will be attached to a deferred device and printed when user
>> reads devices_deferred property.
>>
>> Signed-off-by: Andrzej Hajda <[email protected]>
>> Reviewed-by: Mark Brown <[email protected]>
>> Reviewed-by: Javier Martinez Canillas <[email protected]>
>> Reviewed-by: Andy Shevchenko <[email protected]>
>> Reviewed-by: Rafael J. Wysocki <[email protected]>
>> ---
>> v8:
>> - improved commit message
> I'm totally confused by this series. Can you resend the whole thing,
> as a full series, not just random individual patches in the series
> incremented? It's a pain to try to fish them all out as to which is the
> "latest" with all of the needed reviewed by lines :(
v7 is the latest except this one,which contains only commit message change.
Anyway I will send v8 to make things simple.
Regards
Andrzej
>
> thanks,
>
> greg k-h
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