X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=wrapper%2Fsplice.c;h=7160ea1aa009c148836ce636a27a79c356b3273f;hb=b78104db53f97c10add30016e365855a26f6e01e;hp=357e1ac5a84560dca04613ab718ca76a535d2032;hpb=5a2f5e92e422d87a28581ba97e6b1789ff743bc6;p=lttng-modules.git

diff --git a/wrapper/splice.c b/wrapper/splice.c
index 357e1ac5..7160ea1a 100644
--- a/wrapper/splice.c
+++ b/wrapper/splice.c
@@ -1,28 +1,18 @@
-/*
+/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
+ *
  * wrapper/splice.c
  *
  * wrapper around splice_to_pipe. Using KALLSYMS to get its address when
  * available, else we need to have a kernel that exports this function to GPL
- * modules.
+ * modules. The export was introduced in kernel 4.2.
  *
  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#ifdef CONFIG_KALLSYMS
+#include <lttng-kernel-version.h>
+
+#if (defined(CONFIG_KALLSYMS) \
+	&& (LTTNG_LINUX_VERSION_CODE < LTTNG_KERNEL_VERSION(4,2,0)))
 
 #include <linux/kallsyms.h>
 #include <linux/fs.h>
@@ -41,11 +31,26 @@ ssize_t wrapper_splice_to_pipe(struct pipe_inode_info *pipe,
 	if (splice_to_pipe_sym) {
 		return splice_to_pipe_sym(pipe, spd);
 	} else {
-		printk(KERN_WARNING "LTTng: splice_to_pipe symbol lookup failed.\n");
+		printk_once(KERN_WARNING "LTTng: splice_to_pipe symbol lookup failed.\n");
 		return -ENOSYS;
 	}
 }
 
+/*
+ * Canary function to check for 'splice_to_pipe()' at compile time.
+ *
+ * From 'include/linux/splice.h':
+ *
+ *   extern ssize_t splice_to_pipe(struct pipe_inode_info *,
+ *                                 struct splice_pipe_desc *spd);
+ */
+__attribute__((unused)) static
+ssize_t __canary__splice_to_pipe(struct pipe_inode_info *pipe,
+				struct splice_pipe_desc *spd)
+{
+	return splice_to_pipe(pipe, spd);
+}
+
 #else
 
 #include <linux/fs.h>