linux-kernel - [PATCH RT] printk: hack out emergency loglevel usage

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Date:   Tue, 3 Dec 2019 18:37:53 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        linux-rt-users <linux-rt-users@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        John Ogness <john.ogness@...utronix.de>
Subject: [PATCH RT] printk: hack out emergency loglevel usage

From: John Ogness <john.ogness@...utronix.de>

Instead of using an emergency loglevel to determine if atomic
messages should be printed, use oops_in_progress. This conforms
to the decision that latency-causing atomic messages never be
generated during normal operation.

Signed-off-by: John Ogness <john.ogness@...utronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 kernel/printk/printk.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9d9523431178b..2b4616fd4fd4b 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1767,15 +1767,8 @@ static void call_console_drivers(u64 seq, const char *ext_text, size_t ext_len,
 			con->wrote_history = 1;
 			con->printk_seq = seq - 1;
 		}
-		if (con->write_atomic && level < emergency_console_loglevel &&
-		    facility == 0) {
-			/* skip emergency messages, already printed */
-			if (con->printk_seq < seq)
-				con->printk_seq = seq;
-			continue;
-		}
 		if (con->flags & CON_BOOT && facility == 0) {
-			/* skip emergency messages, already printed */
+			/* skip boot messages, already printed */
 			if (con->printk_seq < seq)
 				con->printk_seq = seq;
 			continue;
@@ -3161,7 +3154,7 @@ static bool console_can_emergency(int level)
 	for_each_console(con) {
 		if (!(con->flags & CON_ENABLED))
 			continue;
-		if (con->write_atomic && level < emergency_console_loglevel)
+		if (con->write_atomic && oops_in_progress)
 			return true;
 		if (con->write && (con->flags & CON_BOOT))
 			return true;
@@ -3177,7 +3170,7 @@ static void call_emergency_console_drivers(int level, const char *text,
 	for_each_console(con) {
 		if (!(con->flags & CON_ENABLED))
 			continue;
-		if (con->write_atomic && level < emergency_console_loglevel) {
+		if (con->write_atomic && oops_in_progress) {
 			con->write_atomic(con, text, text_len);
 			continue;
 		}
-- 
2.24.0