Revert "drm/amdkfd: SMI report dropped event count"

This reverts commit a3ab2d4.

The userspace side for this code is not ready yet so revert
for now.

Reviewed-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Philip Yang <Philip.Yang@amd.com>

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

@@ -42,7 +42,6 @@ struct kfd_smi_client {
 	struct rcu_head rcu;
 	pid_t pid;
 	bool suser;
-	u32 drop_count;
 };
 
 #define KFD_MAX_KFIFO_SIZE	8192
@@ -104,28 +103,12 @@ static ssize_t kfd_smi_ev_read(struct file *filep, char __user *user,
 	}
 	to_copy = min(size, to_copy);
 	ret = kfifo_out(&client->fifo, buf, to_copy);
+	spin_unlock(&client->lock);
 	if (ret <= 0) {
-		spin_unlock(&client->lock);
 		ret = -EAGAIN;
 		goto ret_err;
 	}
 
-	if (client->drop_count) {
-		char msg[KFD_SMI_EVENT_MSG_SIZE];
-		int len;
-
-		len = snprintf(msg, sizeof(msg), "%x ", KFD_SMI_EVENT_DROPPED_EVENT);
-		len += snprintf(msg + len, sizeof(msg) - len,
-				KFD_EVENT_FMT_DROPPED_EVENT(ktime_get_boottime_ns(),
-				client->pid, client->drop_count));
-		if (kfifo_avail(&client->fifo) >= len) {
-			kfifo_in(&client->fifo, msg, len);
-			client->drop_count = 0;
-		}
-	}
-
-	spin_unlock(&client->lock);
-
 	ret = copy_to_user(user, buf, to_copy);
 	if (ret) {
 		ret = -EFAULT;
@@ -199,15 +182,13 @@ static void add_event_to_kfifo(pid_t pid, struct kfd_node *dev,
 	list_for_each_entry_rcu(client, &dev->smi_clients, list) {
 		if (!kfd_smi_ev_enabled(pid, client, smi_event))
 			continue;
-
 		spin_lock(&client->lock);
-		if (!client->drop_count && kfifo_avail(&client->fifo) >= len) {
+		if (kfifo_avail(&client->fifo) >= len) {
 			kfifo_in(&client->fifo, event_msg, len);
 			wake_up_all(&client->wait_queue);
 		} else {
-			client->drop_count++;
-			pr_debug("smi_event(EventID: %u): no space left drop_count %d\n",
-				 smi_event, client->drop_count);
+			pr_debug("smi_event(EventID: %u): no space left\n",
+					smi_event);
 		}
 		spin_unlock(&client->lock);
 	}

include/uapi/linux/kfd_ioctl.h

@@ -530,7 +530,6 @@ enum kfd_smi_event {
 	KFD_SMI_EVENT_QUEUE_EVICTION = 9,
 	KFD_SMI_EVENT_QUEUE_RESTORE = 10,
 	KFD_SMI_EVENT_UNMAP_FROM_GPU = 11,
-	KFD_SMI_EVENT_DROPPED_EVENT = 12,
 
 	/*
 	 * max event number, as a flag bit to get events from all processes,
@@ -611,7 +610,6 @@ struct kfd_ioctl_smi_events_args {
  *    rw: 'W' for write page fault, 'R' for read page fault
  *    rescheduled: 'R' if the queue restore failed and rescheduled to try again
  *    error_code: migrate failure error code, 0 if no error
- *    drop_count: how many events dropped when fifo is full
  */
 #define KFD_EVENT_FMT_UPDATE_GPU_RESET(reset_seq_num, reset_cause)\
 		"%x %s\n", (reset_seq_num), (reset_cause)
@@ -647,10 +645,6 @@ struct kfd_ioctl_smi_events_args {
 		"%lld -%d @%lx(%lx) %x %d\n", (ns), (pid), (addr), (size),\
 		(node), (unmap_trigger)
 
-#define KFD_EVENT_FMT_DROPPED_EVENT(ns, pid, drop_count)\
-		"%lld -%d %d\n", (ns), (pid), (drop_count)
-
-
 /**************************************************************************************************
  * CRIU IOCTLs (Checkpoint Restore In Userspace)
  *