netconsole: append msgid to sysdata

Add msgcounter to the netconsole_target struct to generate message IDs.
If the msgid_enabled attribute is true, increment msgcounter and append
msgid=<msgcounter> to sysdata buffer before sending the message.

Signed-off-by: Gustavo Luiz Duarte <[email protected]>
Reviewed-by: Breno Leitao <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 5e66a568954f..e3722de08ea9 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -125,6 +125,7 @@ enum sysdata_feature {
  * @extradata_complete:	Cached, formatted string of append
  * @userdata_length:	String length of usedata in extradata_complete.
  * @sysdata_fields:	Sysdata features enabled.
+ * @msgcounter:	Message sent counter.
  * @stats:	Packet send stats for the target. Used for debugging.
  * @enabled:	On / off knob to enable / disable target.
  *		Visible from userspace (read-write).
@@ -155,6 +156,8 @@ struct netconsole_target {
 	size_t			userdata_length;
 	/* bit-wise with sysdata_feature bits */
 	u32			sysdata_fields;
+	/* protected by target_list_lock */
+	u32			msgcounter;
 #endif
 	struct netconsole_target_stats stats;
 	bool			enabled;
@@ -1362,6 +1365,14 @@ static int sysdata_append_release(struct netconsole_target *nt, int offset)
 			 init_utsname()->release);
 }
 
+static int sysdata_append_msgid(struct netconsole_target *nt, int offset)
+{
+	wrapping_assign_add(nt->msgcounter, 1);
+	return scnprintf(&nt->extradata_complete[offset],
+			 MAX_EXTRADATA_ENTRY_LEN, " msgid=%u\n",
+			 nt->msgcounter);
+}
+
 /*
  * prepare_extradata - append sysdata at extradata_complete in runtime
  * @nt: target to send message to
@@ -1384,6 +1395,8 @@ static int prepare_extradata(struct netconsole_target *nt)
 		extradata_len += sysdata_append_taskname(nt, extradata_len);
 	if (nt->sysdata_fields & SYSDATA_RELEASE)
 		extradata_len += sysdata_append_release(nt, extradata_len);
+	if (nt->sysdata_fields & SYSDATA_MSGID)
+		extradata_len += sysdata_append_msgid(nt, extradata_len);
 
 	WARN_ON_ONCE(extradata_len >
 		     MAX_EXTRADATA_ENTRY_LEN * MAX_EXTRADATA_ITEMS);