X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=wrapper%2Fsplice.c;h=7160ea1aa009c148836ce636a27a79c356b3273f;hb=e6d0ac2628a8ffe40cbd834b2cf955a3240a12b5;hp=ba224eea62fb39b9ba6a0bcb84b1e1d1dc53305e;hpb=c539a324b020171c10d0fcb100892ac93c17e9e7;p=lttng-modules.git

diff --git a/wrapper/splice.c b/wrapper/splice.c
index ba224eea..7160ea1a 100644
--- a/wrapper/splice.c
+++ b/wrapper/splice.c
@@ -1,19 +1,23 @@
-/*
- * Copyright (C) 2011 Mathieu Desnoyers (mathieu.desnoyers@efficios.com)
+/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
+ *
+ * wrapper/splice.c
  *
- * wrapper around vmalloc_sync_all. Using KALLSYMS to get its address when
+ * 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.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  */
 
-#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>
 #include <linux/splice.h>
-#include "kallsyms.h"
+#include <wrapper/kallsyms.h>
 
 static
 ssize_t (*splice_to_pipe_sym)(struct pipe_inode_info *pipe,
@@ -27,11 +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>