Enable use of DTRACE_PROBE* macros in "spl" module

This change modifies some of the infrastructure for enabling the use of
the DTRACE_PROBE* macros, such that we can use tehm in the "spl" module.

Currently, when the DTRACE_PROBE* macros are used, they get expanded to
create new functions, and these dynamically generated functions become
part of the "zfs" module.

Since the "spl" module does not depend on the "zfs" module, the use of
DTRACE_PROBE* in the "spl" module would result in undefined symbols
being used in the "spl" module. Specifically, DTRACE_PROBE* would turn
into a function call, and the function being called would be a symbol
only contained in the "zfs" module; which results in a linker and/or
runtime error.

Thus, this change adds the necessary logic to the "spl" module, to
mirror the tracing functionality available to the "zfs" module. After
this change, we'll have a "trace_zfs.h" header file which defines the
probes available only to the "zfs" module, and a "trace_spl.h" header
file which defines the probes available only to the "spl" module.

Reviewed by: Brad Lewis <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Prakash Surya <[email protected]>
Closes #9525

6 files changed, 48 insertions, 22 deletions

diff --git a/include/os/linux/spl/sys/Makefile.am b/include/os/linux/spl/sys/Makefile.am
index 7e7d95dc0..251542118 100644
--- a/include/os/linux/spl/sys/Makefile.am
+++ b/include/os/linux/spl/sys/Makefile.am
@@ -45,6 +45,7 @@ KERNEL_H = \
 	$(top_srcdir)/include/os/linux/spl/sys/time.h \
 	$(top_srcdir)/include/os/linux/spl/sys/timer.h \
 	$(top_srcdir)/include/os/linux/spl/sys/trace.h \
+	$(top_srcdir)/include/os/linux/spl/sys/trace_spl.h \
 	$(top_srcdir)/include/os/linux/spl/sys/tsd.h \
 	$(top_srcdir)/include/os/linux/spl/sys/types32.h \
 	$(top_srcdir)/include/os/linux/spl/sys/types.h \
diff --git a/include/os/linux/spl/sys/trace.h b/include/os/linux/spl/sys/trace.h
index e2cd634b4..df859cf2f 100644
--- a/include/os/linux/spl/sys/trace.h
+++ b/include/os/linux/spl/sys/trace.h
@@ -59,14 +59,6 @@
 #include <sys/types.h>
 
 /*
- * The sys/trace_dbgmsg.h header defines tracepoint events for
- * dprintf(), dbgmsg(), and SET_ERROR().
- */
-#define	_SYS_TRACE_DBGMSG_INDIRECT
-#include <sys/trace_dbgmsg.h>
-#undef _SYS_TRACE_DBGMSG_INDIRECT
-
-/*
  * DTRACE_PROBE with 0 arguments is not currently available with
  *  tracepoint events
  */
@@ -174,14 +166,5 @@ EXPORT_SYMBOL(trace_zfs_##name)
 #define	DEFINE_DTRACE_PROBE4(name)	PROTO_DTRACE_PROBE4(name)
 
 #endif /* CREATE_TRACE_POINTS */
-
-/*
- * The sys/trace_dbgmsg.h header defines tracepoint events for
- * dprintf(), dbgmsg(), and SET_ERROR().
- */
-#define	_SYS_TRACE_DBGMSG_INDIRECT
-#include <sys/trace_dbgmsg.h>
-#undef _SYS_TRACE_DBGMSG_INDIRECT
-
 #endif /* HAVE_DECLARE_EVENT_CLASS */
 #endif /* _KERNEL */
diff --git a/include/os/linux/spl/sys/trace_spl.h b/include/os/linux/spl/sys/trace_spl.h
new file mode 100644
index 000000000..6b50d546b
--- /dev/null
+++ b/include/os/linux/spl/sys/trace_spl.h
@@ -0,0 +1,27 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+#ifndef _OS_LINUX_SPL_TRACE_H
+#define	_OS_LINUX_SPL_TRACE_H
+
+#include <sys/trace.h>
+
+#endif
diff --git a/include/os/linux/zfs/sys/Makefile.am b/include/os/linux/zfs/sys/Makefile.am
index ca8d83e26..e061c5ab1 100644
--- a/include/os/linux/zfs/sys/Makefile.am
+++ b/include/os/linux/zfs/sys/Makefile.am
@@ -4,7 +4,7 @@ KERNEL_H = \
 	$(top_srcdir)/include/os/linux/zfs/sys/trace_acl.h \
 	$(top_srcdir)/include/os/linux/zfs/sys/trace_arc.h \
 	$(top_srcdir)/include/os/linux/zfs/sys/trace_common.h \
-	$(top_srcdir)/include/os/linux/zfs/sys/trace_defs.h \
+	$(top_srcdir)/include/os/linux/zfs/sys/trace_zfs.h \
 	$(top_srcdir)/include/os/linux/zfs/sys/trace_dbgmsg.h \
 	$(top_srcdir)/include/os/linux/zfs/sys/trace_dbuf.h \
 	$(top_srcdir)/include/os/linux/zfs/sys/trace_dmu.h \
diff --git a/include/os/linux/zfs/sys/trace_dbgmsg.h b/include/os/linux/zfs/sys/trace_dbgmsg.h
index b2ef529ed..513918d00 100644
--- a/include/os/linux/zfs/sys/trace_dbgmsg.h
+++ b/include/os/linux/zfs/sys/trace_dbgmsg.h
@@ -22,10 +22,16 @@
 #if defined(_KERNEL)
 #if defined(HAVE_DECLARE_EVENT_CLASS)
 
-/* Do not include this file directly. Please use <sys/trace.h> instead. */
-#ifndef _SYS_TRACE_DBGMSG_INDIRECT
-#error "trace_dbgmsg.h included directly"
-#endif
+#undef TRACE_SYSTEM
+#define	TRACE_SYSTEM zfs
+
+#undef TRACE_SYSTEM_VAR
+#define	TRACE_SYSTEM_VAR zfs_dbgmsg
+
+#if !defined(_TRACE_DBGMSG_H) || defined(TRACE_HEADER_MULTI_READ)
+#define	_TRACE_DBGMSG_H
+
+#include <linux/tracepoint.h>
 
 /*
  * This file defines tracepoint events for use by the dbgmsg(),
@@ -67,6 +73,14 @@ DEFINE_EVENT(zfs_dprintf_class, name, \
 /* END CSTYLED */
 DEFINE_DPRINTF_EVENT(zfs_zfs__dprintf);
 
+#endif /* _TRACE_DBGMSG_H */
+
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define	TRACE_INCLUDE_PATH sys
+#define	TRACE_INCLUDE_FILE trace_dbgmsg
+#include <trace/define_trace.h>
+
 #else
 
 DEFINE_DTRACE_PROBE1(zfs__dprintf);
diff --git a/include/os/linux/zfs/sys/trace_defs.h b/include/os/linux/zfs/sys/trace_zfs.h
index aaff65fbc..0e19f8d18 100644
--- a/include/os/linux/zfs/sys/trace_defs.h
+++ b/include/os/linux/zfs/sys/trace_zfs.h
@@ -38,6 +38,7 @@
 #include <sys/trace.h>
 #include <sys/trace_acl.h>
 #include <sys/trace_arc.h>
+#include <sys/trace_dbgmsg.h>
 #include <sys/trace_dbuf.h>
 #include <sys/trace_dmu.h>
 #include <sys/trace_dnode.h>