drm/amdkfd: Reuse function to find a process through pasid

The kfd_lookup_process_by_pasid() is just for that purpose,
so use it instead of repeating the code.

v2: return on the condition (p == NULL) instead of BUG_ON(!p).
Signed-off-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

drivers/gpu/drm/amd/amdkfd/kfd_process.c

@@ -404,26 +404,20 @@ void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
 {
 	struct kfd_process *p;
 	struct kfd_process_device *pdd;
-	int idx, i;
 
 	BUG_ON(dev == NULL);
 
-	idx = srcu_read_lock(&kfd_processes_srcu);
-
 	/*
 	 * Look for the process that matches the pasid. If there is no such
 	 * process, we either released it in amdkfd's own notifier, or there
 	 * is a bug. Unfortunately, there is no way to tell...
 	 */
-	hash_for_each_rcu(kfd_processes_table, i, p, kfd_processes)
-		if (p->pasid == pasid) {
-
-			srcu_read_unlock(&kfd_processes_srcu, idx);
+	p = kfd_lookup_process_by_pasid(pasid);
+	if (!p)
+		return;
 
 	pr_debug("Unbinding process %d from IOMMU\n", pasid);
 
-			mutex_lock(&p->mutex);
-
 	if ((dev->dbgmgr) && (dev->dbgmgr->pasid == p->pasid))
 		kfd_dbgmgr_destroy(dev->dbgmgr);
 
@@ -451,11 +445,6 @@ void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
 	pdd->bound = false;
 
 	mutex_unlock(&p->mutex);
-
-			return;
-		}
-
-	srcu_read_unlock(&kfd_processes_srcu, idx);
 }
 
 struct kfd_process_device *kfd_get_first_process_device_data(struct kfd_process *p)