[RESEND PATCH v3] powerpc/pseries: Limit EPOW reset event warnings

[Kamalesh Babulal]

Kernel prints respective warnings about various EPOW events for
user information/action after parsing EPOW interrupts.Prompting
user to take action depending upon the severity of the event.

At times EPOW reset event warning, such as below could flood
kernel log, over a period of time.

May 25 03:46:34 alp kernel: Non critical power or cooling issue cleared
May 25 03:46:52 alp kernel: Non critical power or cooling issue cleared
May 25 03:53:48 alp kernel: Non critical power or cooling issue cleared
May 25 03:55:46 alp kernel: Non critical power or cooling issue cleared
May 25 03:56:34 alp kernel: Non critical power or cooling issue cleared
May 25 03:59:04 alp kernel: Non critical power or cooling issue cleared
May 25 04:02:01 alp kernel: Non critical power or cooling issue cleared
May 25 04:04:24 alp kernel: Non critical power or cooling issue cleared
May 25 04:07:18 alp kernel: Non critical power or cooling issue cleared
May 25 04:13:04 alp kernel: Non critical power or cooling issue cleared
May 25 04:22:04 alp kernel: Non critical power or cooling issue cleared
May 25 04:22:26 alp kernel: Non critical power or cooling issue cleared
May 25 04:22:36 alp kernel: Non critical power or cooling issue cleared

This patch avoids these multiple EPOW reset warnings by using a boolean
flag. This flag is initialized to false and is set to true upon arrival
of EPOW event. This same flag is checked and reset during EPOW_RESET
scenario to filter out valid EPOW reset events and avoid multiple warning
logs.

Also, merged adjacent pr_err/pr_emerg into single one to reduce
the number of lines printed per warning.

Suggested-by: Vipin K Parashar <vipin at linux.vnet.ibm.com>
[Vipin: edited the changelog]
Cc: Anshuman Khandual <khandual at linux.vnet.ibm.com>
Cc: Anton Blanchard <anton at samba.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Signed-off-by: Kamalesh Babulal <kamalesh at linux.vnet.ibm.com>
---
v3 Changes:
   - Limit warning printed by EPOW RESET event, by guarding it with bool flag.
     Instead of rate limiting all the EPOW events.

v2 Changes:
   - Merged multiple adjacent pr_err/pr_emerg into single line to reduce multi-line
     warnings, based on Michael's comments.

 arch/powerpc/platforms/pseries/ras.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 02e4a17..b30396a 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -40,6 +40,9 @@ static int ras_check_exception_token;
 #define EPOW_SENSOR_TOKEN	9
 #define EPOW_SENSOR_INDEX	0
 
+/* Flag to limit EPOW RESET warning. */
+static bool epow_state;
+
 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
 static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
 
@@ -145,21 +148,27 @@ static void rtas_parse_epow_errlog(struct rtas_error_log *log)
 
 	switch (action_code) {
 	case EPOW_RESET:
-		pr_err("Non critical power or cooling issue cleared");
+		if (epow_state) {
+			pr_err("Non critical power or cooling issue cleared");
+			epow_state = false;
+		}
 		break;
 
 	case EPOW_WARN_COOLING:
-		pr_err("Non critical cooling issue reported by firmware");
-		pr_err("Check RTAS error log for details");
+		pr_err("Non critical cooling issue reported by firmware, "
+		       "Check RTAS error log for details");
+		epow_state = true;
 		break;
 
 	case EPOW_WARN_POWER:
-		pr_err("Non critical power issue reported by firmware");
-		pr_err("Check RTAS error log for details");
+		pr_err("Non critical power issue reported by firmware, "
+		       "Check RTAS error log for details");
+		epow_state = true;
 		break;
 
 	case EPOW_SYSTEM_SHUTDOWN:
 		handle_system_shutdown(epow_log->event_modifier);
+		epow_state = true;
 		break;
 
 	case EPOW_SYSTEM_HALT:
@@ -169,9 +178,8 @@ static void rtas_parse_epow_errlog(struct rtas_error_log *log)
 
 	case EPOW_MAIN_ENCLOSURE:
 	case EPOW_POWER_OFF:
-		pr_emerg("Critical power/cooling issue reported by firmware");
-		pr_emerg("Check RTAS error log for details");
-		pr_emerg("Immediate power off");
+		pr_emerg("Critical power/cooling issue reported by firmware, "
+			 "Check RTAS error log for details. Immediate power off.");
 		emergency_sync();
 		kernel_power_off();
 		break;
@@ -179,6 +187,7 @@ static void rtas_parse_epow_errlog(struct rtas_error_log *log)
 	default:
 		pr_err("Unknown power/cooling event (action code %d)",
 			action_code);
+		epow_state = true;
 	}
 }
 
-- 
2.1.2