On Thu, Dec 20, 2018 at 11:22:46AM +0100, 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 probe_err function introduced recently, > ie. if probe_err will be called with -EPROBE_DEFER instead of printk the > message > will be attached to deferred device and printed when user read > 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]> > --- > v4: > - removed NULL check before kfree, > - coding style tweaking. > v3: > - adjusted deferred_devs_show, to accept newline ended messages, > - changed conditonal check to positive, > - added R-b by Andy. > v2: > - changed __deferred_probe_set_msg args - like in __dev_printk, fits better, > - use kasprintf instead of bunch of code, > - keep consistent format of devices_deferred lines, > - added R-Bs (again I hope changes above are not against it). > --- > --- > drivers/base/base.h | 3 +++ > drivers/base/core.c | 9 +++++---- > drivers/base/dd.c | 21 ++++++++++++++++++++- > 3 files changed, 28 insertions(+), 5 deletions(-) > > diff --git a/drivers/base/base.h b/drivers/base/base.h > index 7a419a7a6235..effbd5e7f9f1 100644 > --- a/drivers/base/base.h > +++ b/drivers/base/base.h > @@ -75,6 +75,7 @@ struct device_private { > struct klist_node knode_driver; > struct klist_node knode_bus; > struct list_head deferred_probe; > + char *deferred_probe_msg; > struct device *device; > }; > #define to_device_private_parent(obj) \ > @@ -113,6 +114,8 @@ 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 __deferred_probe_set_msg(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 7f644f3c41d3..d3eb5aeeaa28 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -3108,6 +3108,7 @@ define_dev_printk_level(_dev_info, KERN_INFO); > * > * This helper implements common pattern present in probe functions for error > * checking: print message if the error is not -EPROBE_DEFER and propagate > it. > + * In case of -EPROBE_DEFER it sets defer probe reason. > * It replaces code sequence: > * if (err != -EPROBE_DEFER) > * dev_err(dev, ...); > @@ -3123,14 +3124,14 @@ int probe_err(const struct device *dev, int err, > const char *fmt, ...) > struct va_format vaf; > va_list args; > > - if (err == -EPROBE_DEFER) > - return err; > - > va_start(args, fmt); > vaf.fmt = fmt; > vaf.va = &args; > > - dev_err(dev, "error %d: %pV", err, &vaf); > + if (err == -EPROBE_DEFER) > + __deferred_probe_set_msg(dev, &vaf); > + else > + dev_err(dev, "error %d: %pV", err, &vaf); > > va_end(args); > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index 88713f182086..857aa4d1d45d 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" > @@ -132,6 +133,8 @@ 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_msg); > + dev->p->deferred_probe_msg = NULL; > } > mutex_unlock(&deferred_probe_mutex); > } > @@ -202,6 +205,21 @@ void device_unblock_probing(void) > driver_deferred_probe_trigger(); > } > > +/* > + * __deferred_probe_set_msg() - Set defer probe reason message for device > + */ > +void __deferred_probe_set_msg(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_msg); > + dev->p->deferred_probe_msg = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
Why do you also need the dev driver string here? Don't you get it automatically when you print out the list in deferred_devs_show()? How about we just wait on this patch, it seems very unneeded. Or at least I can't see who would need this, what can a user do with this information? thanks, greg k-h
