wrapper/splice.c

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   2  *
   3  * wrapper/splice.c
   4  *
   5  * wrapper around splice_to_pipe. Using KALLSYMS to get its address when
   6  * available, else we need to have a kernel that exports this function to GPL
   7  * modules.
   8  *
   9  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  */
  11
  12 #ifdef CONFIG_KALLSYMS
  13
  14 #include <linux/kallsyms.h>
  15 #include <linux/fs.h>
  16 #include <linux/splice.h>
  17 #include <wrapper/kallsyms.h>
  18
  19 static
  20 ssize_t (*splice_to_pipe_sym)(struct pipe_inode_info *pipe,
  21                               struct splice_pipe_desc *spd);
  22
  23 ssize_t wrapper_splice_to_pipe(struct pipe_inode_info *pipe,
  24                                struct splice_pipe_desc *spd)
  25 {
  26         if (!splice_to_pipe_sym)
  27                 splice_to_pipe_sym = (void *) kallsyms_lookup_funcptr("splice_to_pipe");
  28         if (splice_to_pipe_sym) {
  29                 return splice_to_pipe_sym(pipe, spd);
  30         } else {
  31                 printk_once(KERN_WARNING "LTTng: splice_to_pipe symbol lookup failed.\n");
  32                 return -ENOSYS;
  33         }
  34 }
  35
  36 #else
  37
  38 #include <linux/fs.h>
  39 #include <linux/splice.h>
  40
  41 ssize_t wrapper_splice_to_pipe(struct pipe_inode_info *pipe,
  42                                struct splice_pipe_desc *spd)
  43 {
  44         return splice_to_pipe(pipe, spd);
  45 }
  46
  47 #endif