[PATCH i-g-t] lib/igt_device_scan: limit fetched device attributes from udev

Zbigniew Kempczyński zbigniew.kempczynski at intel.com
Thu Jan 30 10:17:02 UTC 2025


On Wed, Jan 29, 2025 at 03:48:49PM +0100, Kamil Konieczny wrote:
> Hi Zbigniew,
> On 2025-01-28 at 09:30:14 +0100, Zbigniew Kempczyński wrote:
> > Tests don't need all attributes so default device scanning is now
> > limited to small list directly used in device filters. To be backward
> > compatible tools like lsgpu still may scan whole attribute list what
> > keeps this behavior intact.
> > 
> > Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> > Cc: Kamil Konieczny <kamil.konieczny at linux.intel.com>
> > Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> > ---
> >  lib/igt_device_scan.c | 69 ++++++++++++++++++++++++++++++-------------
> >  lib/igt_device_scan.h |  1 +
> >  tools/lsgpu.c         |  2 +-
> >  3 files changed, 50 insertions(+), 22 deletions(-)
> > 
> > diff --git a/lib/igt_device_scan.c b/lib/igt_device_scan.c
> > index c36b0efa90..15f6bf5728 100644
> > --- a/lib/igt_device_scan.c
> > +++ b/lib/igt_device_scan.c
> > @@ -22,6 +22,7 @@
> >   *
> >   */
> >  
> > +#include "drmtest.h"
> 
> Could you add a note here why this is needed? Something like
> 
> #include "drmtest.h" /* for macro ARRAY_SIZE */
> 
> >  #include "igt_core.h"
> >  #include "igt_device_scan.h"
> >  #include "igt_list.h"
> > @@ -206,6 +207,8 @@ enum dev_type {
> >  #define STR_INTEGRATED "integrated"
> >  #define STR_DISCRETE "discrete"
> >  
> > +static const char * const attrs[] = { "driver", "sriov_numvfs", "physfn" };
> > +
> >  static inline bool strequal(const char *a, const char *b)
> >  {
> >  	if (a == NULL || b == NULL)
> > @@ -548,24 +551,35 @@ static void get_props(struct udev_device *dev, struct igt_device *idev)
> >   * Function skips sysattrs from blacklist ht (acquiring some values can take
> >   * seconds).
> >   */
> > -static void get_attrs(struct udev_device *dev, struct igt_device *idev)
> > +static void get_attrs(struct udev_device *dev, struct igt_device *idev,
> > +		      bool limit_attrs)
> 
> Why not just two functions instead of a bool var? Below
> you split control flow between two separate paths, imho
> it is better to have two separate functions instead. So
> there will be two functions:
> 
> get_attrs_limited(struct udev_device *dev, struct igt_device *idev)
> 
> get_attrs_all(struct udev_device *dev, struct igt_device *idev)
> 
> and used below.
> 
> >  {
> >  	struct udev_list_entry *entry;
> > +	const char *value;
> >  
> > -	entry = udev_device_get_sysattr_list_entry(dev);
> > -	while (entry) {
> > -		const char *key = udev_list_entry_get_name(entry);
> > -		const char *value;
> > +	if (limit_attrs) {
> > +		for (int i = 0; i < ARRAY_SIZE(attrs); i++) {
> > +			value = udev_device_get_sysattr_value(dev, attrs[i]);
> > +			if (!value)
> > +				continue;
> > +			igt_device_add_attr(idev, attrs[i], value);
> > +			DBG("attr: %s, val: %s\n", attrs[i], value);
> > +		}
> > +	} else {
> > +		entry = udev_device_get_sysattr_list_entry(dev);
> > +		while (entry) {
> > +			const char *key = udev_list_entry_get_name(entry);
> >  
> > -		if (is_on_blacklist(key)) {
> > +			if (is_on_blacklist(key)) {
> > +				entry = udev_list_entry_get_next(entry);
> > +				continue;
> > +			}
> > +
> > +			value = udev_device_get_sysattr_value(dev, key);
> > +			igt_device_add_attr(idev, key, value);
> >  			entry = udev_list_entry_get_next(entry);
> > -			continue;
> > +			DBG("attr: %s, val: %s\n", key, value);
> >  		}
> > -
> > -		value = udev_device_get_sysattr_value(dev, key);
> > -		igt_device_add_attr(idev, key, value);
> > -		entry = udev_list_entry_get_next(entry);
> > -		DBG("attr: %s, val: %s\n", key, value);
> >  	}
> >  }
> >  
> > @@ -639,7 +653,8 @@ static char* strdup_nullsafe(const char* str)
> >   * Fills structure with most usable udev device variables, properties
> >   * and sysattrs.
> >   */
> > -static struct igt_device *igt_device_new_from_udev(struct udev_device *dev)
> > +static struct igt_device *igt_device_new_from_udev(struct udev_device *dev,
> > +						   bool limit_attrs)
> >  {
> >  	struct igt_device *idev = igt_device_new();
> >  
> > @@ -654,7 +669,7 @@ static struct igt_device *igt_device_new_from_udev(struct udev_device *dev)
> >  		idev->drm_render = strdup(idev->devnode);
> >  
> >  	get_props(dev, idev);
> > -	get_attrs(dev, idev);
> > +	get_attrs(dev, idev, limit_attrs);
> 
> So here:
> 	limit_attrs ? get_attrs_limited(dev, idev) :
> 		      get_attrs_all(dev, idev);
> 
> It is not a blocker so with or without it
> Reviewed-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>

Yeah, we may have two different functions instead of adding conditional
inside. I'll rework it.

--
Zbigniew

> 
> Regards,
> Kamil
> 
> >  
> >  	if (is_pci_subsystem(idev)) {
> >  		uint16_t vendor, device;
> > @@ -868,7 +883,8 @@ static struct igt_device *igt_device_from_syspath(const char *syspath)
> >   */
> >  static void update_or_add_parent(struct udev *udev,
> >  				 struct udev_device *dev,
> > -				 struct igt_device *idev)
> > +				 struct igt_device *idev,
> > +				 bool limit_attrs)
> >  {
> >  	struct udev_device *parent_dev;
> >  	struct igt_device *parent_idev;
> > @@ -899,7 +915,7 @@ static void update_or_add_parent(struct udev *udev,
> >  		 * return fresh udev device.
> >  		 */
> >  		parent_dev = udev_device_new_from_syspath(udev, syspath);
> > -		parent_idev = igt_device_new_from_udev(parent_dev);
> > +		parent_idev = igt_device_new_from_udev(parent_dev, limit_attrs);
> >  		udev_device_unref(parent_dev);
> >  
> >  		if (parent_idev)
> > @@ -1000,7 +1016,7 @@ static void index_pci_devices(void)
> >   * Function sorts all found devices to keep same order of bus devices
> >   * for providing predictable search.
> >   */
> > -static void scan_drm_devices(void)
> > +static void scan_drm_devices(bool limit_attrs)
> >  {
> >  	struct udev *udev;
> >  	struct udev_enumerate *enumerate;
> > @@ -1035,9 +1051,9 @@ static void scan_drm_devices(void)
> >  
> >  		path = udev_list_entry_get_name(dev_list_entry);
> >  		udev_dev = udev_device_new_from_syspath(udev, path);
> > -		idev = igt_device_new_from_udev(udev_dev);
> > +		idev = igt_device_new_from_udev(udev_dev, limit_attrs);
> >  		igt_list_add_tail(&idev->link, &igt_devs.all);
> > -		update_or_add_parent(udev, udev_dev, idev);
> > +		update_or_add_parent(udev, udev_dev, idev, limit_attrs);
> >  
> >  		udev_device_unref(udev_dev);
> >  	}
> > @@ -1092,17 +1108,28 @@ void igt_devices_free(void)
> >   *
> >   * Function scans udev in search of gpu devices.
> >   */
> > -void igt_devices_scan(void)
> > +
> > +static void __igt_devices_scan(bool limit_attrs)
> >  {
> >  	if (igt_devs.devs_scanned)
> >  		igt_devices_free();
> >  
> >  	prepare_scan();
> > -	scan_drm_devices();
> > +	scan_drm_devices(limit_attrs);
> >  
> >  	igt_devs.devs_scanned = true;
> >  }
> >  
> > +void igt_devices_scan(void)
> > +{
> > +	__igt_devices_scan(true);
> > +}
> > +
> > +void igt_devices_scan_all_attrs(void)
> > +{
> > +	__igt_devices_scan(false);
> > +}
> > +
> >  static inline void _pr_simple(const char *k, const char *v)
> >  {
> >  	printf("    %-16s: %s\n", k, v);
> > diff --git a/lib/igt_device_scan.h b/lib/igt_device_scan.h
> > index fa90134aa3..92741fe3c7 100644
> > --- a/lib/igt_device_scan.h
> > +++ b/lib/igt_device_scan.h
> > @@ -64,6 +64,7 @@ struct igt_device_card {
> >  };
> >  
> >  void igt_devices_scan(void);
> > +void igt_devices_scan_all_attrs(void);
> >  
> >  void igt_devices_print(const struct igt_devices_print_format *fmt);
> >  void igt_devices_print_vendors(void);
> > diff --git a/tools/lsgpu.c b/tools/lsgpu.c
> > index e482ca6b75..e683900833 100644
> > --- a/tools/lsgpu.c
> > +++ b/tools/lsgpu.c
> > @@ -362,7 +362,7 @@ int main(int argc, char *argv[])
> >  		printf("Notice: Using filter from .igtrc\n");
> >  	}
> >  
> > -	igt_devices_scan();
> > +	igt_devices_scan_all_attrs();
> >  
> >  	if (igt_device != NULL) {
> >  		struct igt_device_card card;
> > -- 
> > 2.34.1
> > 


More information about the igt-dev mailing list