From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 11 May 2011 13:35:35 +0000 (-0400)
Subject: Add splice_to_pipe wrapper
X-Git-Tag: v2.0-pre1~164
X-Git-Url: http://git.liburcu.org/?a=commitdiff_plain;h=90225db5dd17d46fdb281a625ef98780329b0677;p=lttng-modules.git

Add splice_to_pipe wrapper

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/lib/ringbuffer/ring_buffer_splice.c b/lib/ringbuffer/ring_buffer_splice.c
index 531914a4..5fa779f5 100644
--- a/lib/ringbuffer/ring_buffer_splice.c
+++ b/lib/ringbuffer/ring_buffer_splice.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 
+#include "../../wrapper/splice.h"
 #include "../../wrapper/ringbuffer/backend.h"
 #include "../../wrapper/ringbuffer/frontend.h"
 #include "../../wrapper/ringbuffer/vfs.h"
@@ -142,7 +143,7 @@ static int subbuf_splice_actor(struct file *in,
 	if (!spd.nr_pages)
 		return 0;
 
-	return splice_to_pipe(pipe, &spd);
+	return wrapper_splice_to_pipe(pipe, &spd);
 }
 
 ssize_t lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
diff --git a/wrapper/splice.h b/wrapper/splice.h
new file mode 100644
index 00000000..5f400747
--- /dev/null
+++ b/wrapper/splice.h
@@ -0,0 +1,46 @@
+#ifndef _LTT_WRAPPER_SPLICE_H
+#define _LTT_WRAPPER_SPLICE_H
+
+/*
+ * Copyright (C) 2011 Mathieu Desnoyers (mathieu.desnoyers@efficios.com)
+ *
+ * wrapper around vmalloc_sync_all. Using KALLSYMS to get its address when
+ * available, else we need to have a kernel that exports this function to GPL
+ * modules.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#ifdef CONFIG_KALLSYMS
+
+#include <linux/kallsyms.h>
+#include <linux/splice.h>
+
+static inline
+ssize_t wrapper_splice_to_pipe(struct pipe_inode_info *pipe,
+			       struct splice_pipe_desc *spd)
+{
+	ssize_t (*splice_to_pipe_sym)(struct pipe_inode_info *pipe,
+				      struct splice_pipe_desc *spd);
+
+	splice_to_pipe_sym = (void *) kallsyms_lookup_name("splice_to_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");
+		return -ENOSYS;
+	}
+}
+#else
+
+#include <linux/splice.h>
+
+static inline
+ssize_t wrapper_splice_to_pipe(struct pipe_inode_info *pipe,
+			       struct splice_pipe_desc *spd)
+{
+	return splice_to_pipe(pipe, spd);
+}
+#endif
+
+#endif /* _LTT_WRAPPER_SPLICE_H */