Re: [Intel-xe] [v2 1/2] drm/xe: Add a new memory directory under tile

["Sundaresan, Sujaritha" <sujaritha.sundaresan@intel.com>]

On 12/6/2023 5:23 PM, Gupta, Anshuman wrote:
>
>> -----Original Message-----
>> From: Intel-xe <intel-xe-bounces@lists.freedesktop.org> On Behalf Of Sujaritha
>> Sundaresan
>> Sent: Wednesday, December 6, 2023 10:18 AM
>> To: intel-xe@lists.freedesktop.org
>> Cc: Sundaresan, Sujaritha <sujaritha.sundaresan@intel.com>; Vivi, Rodrigo
>> <rodrigo.vivi@intel.com>
>> Subject: [Intel-xe] [v2 1/2] drm/xe: Add a new memory directory under tile
>>
>> Add a new memory directory under /device/tile<n> and move physical_vram_size
>> attribute to the new directory.
>>
>> New hierarchy:
>>
>> /device/tile<n>/memory/physical_vram_size_bytes
>>
>> v2: Fix heading typo (Riana)
>>      Fix cleanup error on unload/reload cycle
>>
>> Signed-off-by: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_tile_sysfs.c | 15 ++++++++++++---
>>   1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_tile_sysfs.c
>> b/drivers/gpu/drm/xe/xe_tile_sysfs.c
>> index 16376607c68f..e8ce4d9270e6 100644
>> --- a/drivers/gpu/drm/xe/xe_tile_sysfs.c
>> +++ b/drivers/gpu/drm/xe/xe_tile_sysfs.c
>> @@ -24,7 +24,8 @@ static ssize_t
>>   physical_vram_size_bytes_show(struct device *kdev, struct device_attribute
>> *attr,
>>   			      char *buf)
>>   {
>> -	struct xe_tile *tile = kobj_to_tile(&kdev->kobj);
>> +	struct kobject *kobj = &kdev->kobj;
>> +	struct xe_tile *tile = kobj_to_tile(kobj->parent);
>>
>>   	return sysfs_emit(buf, "%llu\n", tile->mem.vram.actual_physical_size);
>>   }
>> @@ -38,7 +39,7 @@ static void tile_sysfs_fini(struct drm_device *drm, void
>> *arg)  {
>>   	struct xe_tile *tile = arg;
>>
>> -	kobject_put(tile->sysfs);
>> +	kobject_del(tile->sysfs);
> Why kobekct_del instead of kobject_put?
> Thanks,
> Anshuman Gupta.

Hi Anshuman,

Basically when sanity checking, after reload we see that we are not 
doing a proper cleanup.

kobject_put will only decrement the ref count and possibly free the kobject.

But that is not happening in this case. There is a duplicate remaining 
of the tile directory.

This required a clean unregister of the parent from sysfs hence the use 
of kobject_del.

Thanks,

Suja

>>   }
>>
>>   void xe_tile_sysfs_init(struct xe_tile *tile) @@ -46,6 +47,7 @@ void
>> xe_tile_sysfs_init(struct xe_tile *tile)
>>   	struct xe_device *xe = tile_to_xe(tile);
>>   	struct device *dev = xe->drm.dev;
>>   	struct kobj_tile *kt;
>> +	struct kobject *kobj;
>>   	int err;
>>
>>   	kt = kzalloc(sizeof(*kt), GFP_KERNEL); @@ -64,8 +66,15 @@ void
>> xe_tile_sysfs_init(struct xe_tile *tile)
>>
>>   	tile->sysfs = &kt->base;
>>
>> +	kobj = kobject_create_and_add("memory", tile->sysfs);
>> +	if (!kobj) {
>> +		kobject_put(kobj);
>> +		drm_warn(&xe->drm, "%s failed, err: %d\n", __func__, -
>> ENOMEM);
>> +		return;
>> +	}
>> +
>>   	if (IS_DGFX(xe) && xe->info.platform != XE_DG1 &&
>> -	    sysfs_create_file(tile->sysfs, physical_memsize_attr))
>> +	    sysfs_create_file(kobj, physical_memsize_attr))
>>   		drm_warn(&xe->drm,
>>   			 "Sysfs creation to read addr_range per tile failed\n");
>>
>> --
>> 2.25.1