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 <brad.lewis@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <prakash.surya@delphix.com>
Closes #9525

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 \

include/os/linux/spl/sys/trace.h

@@ -58,14 +58,6 @@
 #include <linux/tracepoint.h>
 #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 */

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

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 \

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);

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>

include/sys/zfs_context.h

@@ -116,7 +116,7 @@
 #include <sys/sunddi.h>
 #include <sys/debug.h>
 #include <sys/utsname.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 /*
  * Stack

lib/libspl/include/sys/Makefile.am

@@ -35,7 +35,8 @@ libspl_HEADERS = \
 	$(top_srcdir)/lib/libspl/include/sys/sunddi.h \
 	$(top_srcdir)/lib/libspl/include/sys/systeminfo.h \
 	$(top_srcdir)/lib/libspl/include/sys/time.h \
-	$(top_srcdir)/lib/libspl/include/sys/trace_defs.h \
+	$(top_srcdir)/lib/libspl/include/sys/trace_spl.h \
+	$(top_srcdir)/lib/libspl/include/sys/trace_zfs.h \
 	$(top_srcdir)/lib/libspl/include/sys/types32.h \
 	$(top_srcdir)/lib/libspl/include/sys/types.h \
 	$(top_srcdir)/lib/libspl/include/sys/tzfile.h \

lib/libspl/include/sys/trace_spl.h

@@ -0,0 +1,24 @@
+/* Here to keep the libspl build happy */
+
+#ifndef _LIBSPL_SPL_TRACE_H
+#define	_LIBSPL_SPL_TRACE_H
+
+/*
+ * The set-error SDT probe is extra static, in that we declare its fake
+ * function literally, rather than with the DTRACE_PROBE1() macro.  This is
+ * necessary so that SET_ERROR() can evaluate to a value, which wouldn't
+ * be possible if it required multiple statements (to declare the function
+ * and then call it).
+ *
+ * SET_ERROR() uses the comma operator so that it can be used without much
+ * additional code.  For example, "return (EINVAL);" becomes
+ * "return (SET_ERROR(EINVAL));".  Note that the argument will be evaluated
+ * twice, so it should not have side effects (e.g. something like:
+ * "return (SET_ERROR(log_error(EINVAL, info)));" would log the error twice).
+ */
+#undef SET_ERROR
+#define	SET_ERROR(err) \
+	(__set_error(__FILE__, __func__, __LINE__, err), err)
+
+
+#endif

module/os/linux/spl/Makefile.in

@@ -11,6 +11,7 @@ $(MODULE)-objs += ../os/linux/spl/spl-proc.o
 $(MODULE)-objs += ../os/linux/spl/spl-procfs-list.o
 $(MODULE)-objs += ../os/linux/spl/spl-taskq.o
 $(MODULE)-objs += ../os/linux/spl/spl-thread.o
+$(MODULE)-objs += ../os/linux/spl/spl-trace.o
 $(MODULE)-objs += ../os/linux/spl/spl-tsd.o
 $(MODULE)-objs += ../os/linux/spl/spl-vmem.o
 $(MODULE)-objs += ../os/linux/spl/spl-vnode.o

module/os/linux/spl/spl-trace.c

@@ -0,0 +1,30 @@
+/*
+ * 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
+ */
+
+/*
+ * Each DTRACE_PROBE must define its trace point in one (and only one)
+ * source file, so this dummy file exists for that purpose.
+ */
+
+#ifdef _KERNEL
+#define	CREATE_TRACE_POINTS
+#include <sys/trace.h>
+#endif

module/os/linux/zfs/arc_os.c

@@ -54,7 +54,7 @@
 #include <sys/zthr.h>
 #include <zfs_fletcher.h>
 #include <sys/arc_impl.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/aggsum.h>
 
 int64_t last_free_memory;

module/os/linux/zfs/trace.c

@@ -41,6 +41,7 @@
 #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>

module/os/linux/zfs/zfs_debug.c

@@ -24,6 +24,7 @@
  */
 
 #include <sys/zfs_context.h>
+#include <sys/trace_zfs.h>
 
 typedef struct zfs_dbgmsg {
 	procfs_list_node_t	zdm_node;

module/os/linux/zfs/zio_os.c

@@ -29,7 +29,7 @@
 #include <sys/zio.h>
 #include <sys/zio_impl.h>
 #include <sys/time.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 void
 zio_delay_interrupt(zio_t *zio)

module/zfs/arc.c

@@ -297,7 +297,7 @@
 #include <sys/zthr.h>
 #include <zfs_fletcher.h>
 #include <sys/arc_impl.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/aggsum.h>
 #include <sys/cityhash.h>
 

module/zfs/dbuf.c

@@ -44,7 +44,7 @@
 #include <sys/zfeature.h>
 #include <sys/blkptr.h>
 #include <sys/range_tree.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/callb.h>
 #include <sys/abd.h>
 #include <sys/vdev.h>

module/zfs/dmu.c

@@ -49,7 +49,7 @@
 #include <sys/sa.h>
 #include <sys/zfeature.h>
 #include <sys/abd.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/zfs_rlock.h>
 #ifdef _KERNEL
 #include <sys/vmsystm.h>

module/zfs/dmu_tx.c

@@ -37,7 +37,7 @@
 #include <sys/sa.h>
 #include <sys/sa_impl.h>
 #include <sys/zfs_context.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 typedef void (*dmu_tx_hold_func_t)(dmu_tx_t *tx, struct dnode *dn,
     uint64_t arg1, uint64_t arg2);

module/zfs/dnode.c

@@ -37,7 +37,7 @@
 #include <sys/zio.h>
 #include <sys/dmu_zfetch.h>
 #include <sys/range_tree.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/zfs_project.h>
 
 dnode_stats_t dnode_stats = {

module/zfs/dsl_pool.c

@@ -48,7 +48,7 @@
 #include <sys/zfeature.h>
 #include <sys/zil_impl.h>
 #include <sys/dsl_userhold.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/mmp.h>
 
 /*

module/zfs/multilist.c

@@ -18,7 +18,7 @@
 
 #include <sys/zfs_context.h>
 #include <sys/multilist.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 /* needed for spa_get_random() */
 #include <sys/spa.h>

module/zfs/rrwlock.c

@@ -28,7 +28,7 @@
 
 #include <sys/refcount.h>
 #include <sys/rrwlock.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 /*
  * This file contains the implementation of a re-entrant read

module/zfs/txg.c

@@ -33,7 +33,7 @@
 #include <sys/dsl_scan.h>
 #include <sys/zil.h>
 #include <sys/callb.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 /*
  * ZFS Transaction Groups

module/zfs/vdev_removal.c

@@ -47,7 +47,7 @@
 #include <sys/abd.h>
 #include <sys/vdev_initialize.h>
 #include <sys/vdev_trim.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 /*
  * This file contains the necessary logic to remove vdevs from a

module/zfs/zil.c

@@ -41,7 +41,7 @@
 #include <sys/dmu_tx.h>
 #include <sys/dsl_pool.h>
 #include <sys/metaslab.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/abd.h>
 
 /*

module/zfs/zio.c

@@ -44,7 +44,7 @@
 #include <sys/dsl_scan.h>
 #include <sys/metaslab_impl.h>
 #include <sys/time.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 #include <sys/abd.h>
 #include <sys/dsl_crypt.h>
 #include <sys/cityhash.h>

module/zfs/zrlock.c

@@ -39,7 +39,7 @@
  * function calls.
  */
 #include <sys/zrlock.h>
-#include <sys/trace_defs.h>
+#include <sys/trace_zfs.h>
 
 /*
  * A ZRL can be locked only while there are zero references, so ZRL_LOCKED is