* [RFC PATCH v2] driver core: add a debugfs entry to show deferred devices
@ 2018-06-19 18:33 Javier Martinez Canillas
2018-06-19 19:53 ` Andy Shevchenko
0 siblings, 1 reply; 5+ messages in thread
From: Javier Martinez Canillas @ 2018-06-19 18:33 UTC (permalink / raw)
To: linux-kernel
Cc: Mark Brown, Tomeu Vizoso, linux-arm-kernel, Rob Herring,
Javier Martinez Canillas, Greg Kroah-Hartman
For debugging purposes it may be useful to know what are the devices whose
probe function was deferred. Add a debugfs entry showing that information.
$ cat /sys/kernel/debug/deferred_devices
48070000.i2c:twl@48:bci
musb-hdrc.0.auto
omapdrm.0
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---
Changes in v2:
- Remove unneeded ret variable from deferred_devs_show()
drivers/base/dd.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 1435d7281c6..d95bd4636fc 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -224,6 +224,42 @@ void device_unblock_probing(void)
driver_deferred_probe_trigger();
}
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+#include <linux/debugfs.h>
+
+static struct dentry *deferred_devices;
+
+/*
+ * deferred_devs_show() - Show the devices in the deferred probe pending list.
+ */
+static int deferred_devs_show(struct seq_file *s, void *data)
+{
+ struct device_private *curr;
+
+ 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));
+
+ mutex_unlock(&deferred_probe_mutex);
+
+ return 0;
+}
+
+static int deferred_devs_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, deferred_devs_show, inode->i_private);
+}
+
+static const struct file_operations deferred_devs_fops = {
+ .owner = THIS_MODULE,
+ .open = deferred_devs_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
+
/**
* deferred_probe_initcall() - Enable probing of deferred devices
*
@@ -233,6 +269,14 @@ void device_unblock_probing(void)
*/
static int deferred_probe_initcall(void)
{
+ if (IS_ENABLED(CONFIG_DEBUG_FS)) {
+ deferred_devices = debugfs_create_file("deferred_devices",
+ 0444, NULL, NULL,
+ &deferred_devs_fops);
+ if (!deferred_devices)
+ return -ENOMEM;
+ }
+
driver_deferred_probe_enable = true;
driver_deferred_probe_trigger();
/* Sort as many dependencies as possible before exiting initcalls */
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [RFC PATCH v2] driver core: add a debugfs entry to show deferred devices
2018-06-19 18:33 [RFC PATCH v2] driver core: add a debugfs entry to show deferred devices Javier Martinez Canillas
@ 2018-06-19 19:53 ` Andy Shevchenko
2018-06-19 19:55 ` Andy Shevchenko
0 siblings, 1 reply; 5+ messages in thread
From: Andy Shevchenko @ 2018-06-19 19:53 UTC (permalink / raw)
To: Javier Martinez Canillas
Cc: Linux Kernel Mailing List, Mark Brown, Tomeu Vizoso,
linux-arm Mailing List, Rob Herring, Greg Kroah-Hartman
On Tue, Jun 19, 2018 at 9:33 PM, Javier Martinez Canillas
<javierm@redhat.com> wrote:
> For debugging purposes it may be useful to know what are the devices whose
> probe function was deferred. Add a debugfs entry showing that information.
>
> $ cat /sys/kernel/debug/deferred_devices
> 48070000.i2c:twl@48:bci
> musb-hdrc.0.auto
> omapdrm.0
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +#include <linux/debugfs.h>
> +
> +static struct dentry *deferred_devices;
> +
> +/*
> + * deferred_devs_show() - Show the devices in the deferred probe pending list.
> + */
> +static int deferred_devs_show(struct seq_file *s, void *data)
> +{
> + struct device_private *curr;
> +
> + 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));
> +
> + mutex_unlock(&deferred_probe_mutex);
> +
> + return 0;
> +}
> +
> +static int deferred_devs_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, deferred_devs_show, inode->i_private);
> +}
> +
> +static const struct file_operations deferred_devs_fops = {
> + .owner = THIS_MODULE,
> + .open = deferred_devs_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> +};
Isn't this DEFINE_SHOW_ATTRIBUTE() ?
> +#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
> +
> /**
> * deferred_probe_initcall() - Enable probing of deferred devices
> *
> @@ -233,6 +269,14 @@ void device_unblock_probing(void)
> */
> static int deferred_probe_initcall(void)
> {
> + if (IS_ENABLED(CONFIG_DEBUG_FS)) {
> + deferred_devices = debugfs_create_file("deferred_devices",
> + 0444, NULL, NULL,
> + &deferred_devs_fops);
> + if (!deferred_devices)
> + return -ENOMEM;
> + }
> +
> driver_deferred_probe_enable = true;
> driver_deferred_probe_trigger();
> /* Sort as many dependencies as possible before exiting initcalls */
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH v2] driver core: add a debugfs entry to show deferred devices
2018-06-19 19:53 ` Andy Shevchenko
@ 2018-06-19 19:55 ` Andy Shevchenko
2018-06-19 20:29 ` Greg Kroah-Hartman
2018-06-19 20:54 ` Javier Martinez Canillas
0 siblings, 2 replies; 5+ messages in thread
From: Andy Shevchenko @ 2018-06-19 19:55 UTC (permalink / raw)
To: Javier Martinez Canillas
Cc: Linux Kernel Mailing List, Mark Brown, Tomeu Vizoso,
linux-arm Mailing List, Rob Herring, Greg Kroah-Hartman
On Tue, Jun 19, 2018 at 10:53 PM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Tue, Jun 19, 2018 at 9:33 PM, Javier Martinez Canillas
> <javierm@redhat.com> wrote:
>> For debugging purposes it may be useful to know what are the devices whose
>> probe function was deferred. Add a debugfs entry showing that information.
>> +static int deferred_devs_open(struct inode *inode, struct file *file)
>> +{
>> + return single_open(file, deferred_devs_show, inode->i_private);
>> +}
>> +
>> +static const struct file_operations deferred_devs_fops = {
>> + .owner = THIS_MODULE,
>> + .open = deferred_devs_open,
>> + .read = seq_read,
>> + .llseek = seq_lseek,
>> + .release = single_release,
>> +};
>
> Isn't this DEFINE_SHOW_ATTRIBUTE() ?
Besides that, you are summoning Greg's dark side :-)
See below.
>> + if (IS_ENABLED(CONFIG_DEBUG_FS)) {
>> + deferred_devices = debugfs_create_file("deferred_devices",
>> + 0444, NULL, NULL,
>> + &deferred_devs_fops);
>> + if (!deferred_devices)
>> + return -ENOMEM;
This must not prevent the execution. So, the check introduces actually
a regression.
>> + }
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH v2] driver core: add a debugfs entry to show deferred devices
2018-06-19 19:55 ` Andy Shevchenko
@ 2018-06-19 20:29 ` Greg Kroah-Hartman
2018-06-19 20:54 ` Javier Martinez Canillas
1 sibling, 0 replies; 5+ messages in thread
From: Greg Kroah-Hartman @ 2018-06-19 20:29 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Javier Martinez Canillas, Linux Kernel Mailing List, Mark Brown,
Tomeu Vizoso, linux-arm Mailing List, Rob Herring
On Tue, Jun 19, 2018 at 10:55:20PM +0300, Andy Shevchenko wrote:
> On Tue, Jun 19, 2018 at 10:53 PM, Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Tue, Jun 19, 2018 at 9:33 PM, Javier Martinez Canillas
> > <javierm@redhat.com> wrote:
> >> For debugging purposes it may be useful to know what are the devices whose
> >> probe function was deferred. Add a debugfs entry showing that information.
>
> >> +static int deferred_devs_open(struct inode *inode, struct file *file)
> >> +{
> >> + return single_open(file, deferred_devs_show, inode->i_private);
> >> +}
> >> +
> >> +static const struct file_operations deferred_devs_fops = {
> >> + .owner = THIS_MODULE,
> >> + .open = deferred_devs_open,
> >> + .read = seq_read,
> >> + .llseek = seq_lseek,
> >> + .release = single_release,
> >> +};
> >
> > Isn't this DEFINE_SHOW_ATTRIBUTE() ?
>
> Besides that, you are summoning Greg's dark side :-)
> See below.
>
> >> + if (IS_ENABLED(CONFIG_DEBUG_FS)) {
> >> + deferred_devices = debugfs_create_file("deferred_devices",
> >> + 0444, NULL, NULL,
> >> + &deferred_devs_fops);
>
> >> + if (!deferred_devices)
> >> + return -ENOMEM;
>
> This must not prevent the execution. So, the check introduces actually
> a regression.
Awe, you beat me to it :)
Also, I don't usually comment on RFC patches, as that shows the author
really doesn't think that the code is ready to be reviewed/merged...
thanks,
greg k-h
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH v2] driver core: add a debugfs entry to show deferred devices
2018-06-19 19:55 ` Andy Shevchenko
2018-06-19 20:29 ` Greg Kroah-Hartman
@ 2018-06-19 20:54 ` Javier Martinez Canillas
1 sibling, 0 replies; 5+ messages in thread
From: Javier Martinez Canillas @ 2018-06-19 20:54 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Linux Kernel Mailing List, Mark Brown, Tomeu Vizoso,
linux-arm Mailing List, Rob Herring, Greg Kroah-Hartman
Hello Andy,
Thanks a lot for your feedback.
On 06/19/2018 09:55 PM, Andy Shevchenko wrote:
> On Tue, Jun 19, 2018 at 10:53 PM, Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
>> On Tue, Jun 19, 2018 at 9:33 PM, Javier Martinez Canillas
>> <javierm@redhat.com> wrote:
>>> For debugging purposes it may be useful to know what are the devices whose
>>> probe function was deferred. Add a debugfs entry showing that information.
>
>>> +static int deferred_devs_open(struct inode *inode, struct file *file)
>>> +{
>>> + return single_open(file, deferred_devs_show, inode->i_private);
>>> +}
>>> +
>>> +static const struct file_operations deferred_devs_fops = {
>>> + .owner = THIS_MODULE,
>>> + .open = deferred_devs_open,
>>> + .read = seq_read,
>>> + .llseek = seq_lseek,
>>> + .release = single_release,
>>> +};
>>
>> Isn't this DEFINE_SHOW_ATTRIBUTE() ?
>
Indeed.
> Besides that, you are summoning Greg's dark side :-)
> See below.
>
>>> + if (IS_ENABLED(CONFIG_DEBUG_FS)) {
>>> + deferred_devices = debugfs_create_file("deferred_devices",
>>> + 0444, NULL, NULL,
>>> + &deferred_devs_fops);
>
>>> + if (!deferred_devices)
>>> + return -ENOMEM;
>
> This must not prevent the execution. So, the check introduces actually
> a regression.
>
Fair enough, I'll fix these an re-spin the patch.
>>> + }
>
Best regards,
--
Javier Martinez Canillas
Software Engineer - Desktop Hardware Enablement
Red Hat
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2018-06-19 18:33 [RFC PATCH v2] driver core: add a debugfs entry to show deferred devices Javier Martinez Canillas
2018-06-19 19:53 ` Andy Shevchenko
2018-06-19 19:55 ` Andy Shevchenko
2018-06-19 20:29 ` Greg Kroah-Hartman
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