From 119138701222d9e999900e11f30b1d0816fc5dd9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Attila=20F=C3=BCl=C3=B6p?= <attila@fueloep.org>
Date: Tue, 7 Mar 2023 22:44:11 +0100
Subject: [PATCH] spl: Add cmn_err_once() to log a message only on the first
 call
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Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes #14567
---
 include/os/freebsd/spl/sys/cmn_err.h | 33 +++++++++++++++++++++++++++
 include/os/linux/spl/sys/cmn_err.h   | 17 ++++++++++++++
 lib/libspl/include/sys/cmn_err.h     | 34 ++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)

diff --git a/include/os/freebsd/spl/sys/cmn_err.h b/include/os/freebsd/spl/sys/cmn_err.h
index a8f9a88247cd..dd3da7da205a 100644
--- a/include/os/freebsd/spl/sys/cmn_err.h
+++ b/include/os/freebsd/spl/sys/cmn_err.h
@@ -33,6 +33,7 @@
 
 #if !defined(_ASM)
 #include <sys/_stdarg.h>
+#include <sys/atomic.h>
 #endif
 
 #ifdef	__cplusplus
@@ -73,6 +74,38 @@ extern void vuprintf(const char *, __va_list)
 extern void panic(const char *, ...)
     __attribute__((format(printf, 1, 2), __noreturn__));
 
+#define	cmn_err_once(ce, ...)				\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		cmn_err(ce, __VA_ARGS__);		\
+	}						\
+}
+
+#define	vcmn_err_once(ce, fmt, ap)			\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		vcmn_err(ce, fmt, ap);			\
+	}						\
+}
+
+#define	zcmn_err_once(zone, ce, ...)			\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		zcmn_err(zone, ce, __VA_ARGS__);	\
+	}						\
+}
+
+#define	vzcmn_err_once(zone, ce, fmt, ap)		\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		vzcmn_err(zone, ce, fmt, ap);		\
+	}						\
+}
+
 #endif /* !_ASM */
 
 #ifdef	__cplusplus
diff --git a/include/os/linux/spl/sys/cmn_err.h b/include/os/linux/spl/sys/cmn_err.h
index 161bcf9b3a46..7ca2a86be9e8 100644
--- a/include/os/linux/spl/sys/cmn_err.h
+++ b/include/os/linux/spl/sys/cmn_err.h
@@ -29,6 +29,7 @@
 #else
 #include <stdarg.h>
 #endif
+#include <sys/atomic.h>
 
 #define	CE_CONT		0 /* continuation */
 #define	CE_NOTE		1 /* notice */
@@ -45,4 +46,20 @@ extern void vpanic(const char *, va_list)
 
 #define	fm_panic	panic
 
+#define	cmn_err_once(ce, ...)				\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		cmn_err(ce, __VA_ARGS__);		\
+	}						\
+}
+
+#define	vcmn_err_once(ce, fmt, ap)			\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		vcmn_err(ce, fmt, ap);			\
+	}						\
+}
+
 #endif /* SPL_CMN_ERR_H */
diff --git a/lib/libspl/include/sys/cmn_err.h b/lib/libspl/include/sys/cmn_err.h
index f4db082c22a4..6c71dcb8ec13 100644
--- a/lib/libspl/include/sys/cmn_err.h
+++ b/lib/libspl/include/sys/cmn_err.h
@@ -27,4 +27,38 @@
 #ifndef _LIBSPL_SYS_CMN_ERR_H
 #define	_LIBSPL_SYS_CMN_ERR_H
 
+#include <atomic.h>
+
+#define	cmn_err_once(ce, ...)				\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		cmn_err(ce, __VA_ARGS__);		\
+	}						\
+}
+
+#define	vcmn_err_once(ce, fmt, ap)			\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		vcmn_err(ce, fmt, ap);			\
+	}						\
+}
+
+#define	zcmn_err_once(zone, ce, ...)			\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		zcmn_err(zone, ce, __VA_ARGS__);	\
+	}						\
+}
+
+#define	vzcmn_err_once(zone, ce, fmt, ap)		\
+{							\
+	static volatile uint32_t printed = 0;		\
+	if (atomic_cas_32(&printed, 0, 1) == 0) {	\
+		vzcmn_err(zone, ce, fmt, ap);		\
+	}						\
+}
+
 #endif