drm/xe: Add process name to devcoredump

Process name help us track what application caused the gpug hang, this
is crucial when running several applications at the same time.

v2:
- handle Xe KMD exec_queues without VM

v3:
- use get_pid_task() (suggested by Nirmoy)

Cc: Rodrigo Vivi <[e-mail]>
Cc: Nirmoy Das <[e-mail]>
Signed-off-by: José Roberto de Souza <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Signed-off-by: Rodrigo Vivi <[e-mail]>

drivers/gpu/drm/xe/xe_devcoredump.c

···
 	drm_printf(&p, "Snapshot time: %lld.%09ld\n", ts.tv_sec, ts.tv_nsec);
 	ts = ktime_to_timespec64(ss->boot_time);
 	drm_printf(&p, "Uptime: %lld.%09ld\n", ts.tv_sec, ts.tv_nsec);
+	drm_printf(&p, "Process: %s\n", ss->process_name);
 	xe_device_snapshot_print(xe, &p);
 
 	drm_printf(&p, "\n**** GuC CT ****\n");
···
 	enum xe_hw_engine_id id;
 	u32 adj_logical_mask = q->logical_mask;
 	u32 width_mask = (0x1 << q->width) - 1;
+	const char *process_name = "no process";
+	struct task_struct *task = NULL;
+
 	int i;
 	bool cookie;
 
 	ss->snapshot_time = ktime_get_real();
 	ss->boot_time = ktime_get_boottime();
+
+	if (q->vm) {
+		task = get_pid_task(q->vm->xef->drm->pid, PIDTYPE_PID);
+		if (task)
+			process_name = task->comm;
+	}
+	snprintf(ss->process_name, sizeof(ss->process_name), process_name);
+	if (task)
+		put_task_struct(task);
 
 	ss->gt = q->gt;
 	INIT_WORK(&ss->work, xe_devcoredump_deferred_snap_work);

drivers/gpu/drm/xe/xe_devcoredump_types.h

···
 	ktime_t snapshot_time;
 	/** @boot_time:  Relative boot time so the uptime can be calculated. */
 	ktime_t boot_time;
+	/** @process_name: Name of process that triggered this gpu hang */
+	char process_name[TASK_COMM_LEN];
 
 	/** @gt: Affected GT, used by forcewake for delayed capture */
 	struct xe_gt *gt;