1 /*-
2 * Copyright (c) 2025 The FreeBSD Foundation
3 * Copyright (c) 2025 Jean-Sébastien Pédron
4 *
5 * This software was developed by Jean-Sébastien Pédron under sponsorship
6 * from the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/param.h>
31 #include <sys/file.h>
32 #include <sys/filedesc.h>
33
34 #include <linux/eventfd.h>
35
36 struct eventfd_ctx *
lkpi_eventfd_ctx_fdget(int fd)37 lkpi_eventfd_ctx_fdget(int fd)
38 {
39 struct file *fp;
40 struct eventfd_ctx *ctx;
41
42 /* Lookup file pointer by file descriptor index. */
43 if (fget_unlocked(curthread, fd, &cap_no_rights, &fp) != 0)
44 return (ERR_PTR(-EBADF));
45
46 /*
47 * eventfd_get() bumps the refcount, so we can safely release the
48 * reference on the file itself afterwards.
49 */
50 ctx = eventfd_get(fp);
51 fdrop(fp, curthread);
52
53 if (ctx == NULL)
54 return (ERR_PTR(-EBADF));
55
56 return (ctx);
57 }
58
59 void
lkpi_eventfd_ctx_put(struct eventfd_ctx * ctx)60 lkpi_eventfd_ctx_put(struct eventfd_ctx *ctx)
61 {
62 eventfd_put(ctx);
63 }
64