1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2014 Gleb Smirnoff <glebius@FreeBSD.org>
5 * Copyright (c) 2003-2004 Alan L. Cox <alc@cs.rice.edu>
6 * All rights reserved.
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#ifndef _SYS_SF_BUF_H_
31#define _SYS_SF_BUF_H_
32
33struct sfstat { /* sendfile statistics */
34 uint64_t sf_syscalls; /* times sendfile was called */
35 uint64_t sf_noiocnt; /* times sendfile didn't require I/O */
36 uint64_t sf_iocnt; /* times sendfile had to do disk I/O */
37 uint64_t sf_pages_read; /* pages read as part of a request */
38 uint64_t sf_pages_valid; /* pages were valid for a request */
39 uint64_t sf_rhpages_requested; /* readahead pages requested */
40 uint64_t sf_rhpages_read; /* readahead pages read */
41 uint64_t sf_busy; /* times aborted on a busy page */
42 uint64_t sf_allocfail; /* times sfbuf allocation failed */
43 uint64_t sf_allocwait; /* times sfbuf allocation had to wait */
44 uint64_t sf_pages_bogus; /* times bogus page was used */
45};
46
47#ifdef _KERNEL
48#include <sys/types.h>
49#include <sys/systm.h>
50#include <sys/counter.h>
51#include <vm/vm.h>
52#include <vm/vm_param.h>
53#include <vm/vm_page.h>
54
55/*
56 * Sf_bufs, or sendfile(2) buffers provide a vm_page that is mapped
57 * into kernel address space. Note, that they aren't used only
58 * by sendfile(2)!
59 *
60 * Sf_bufs could be implemented as a feature of vm_page_t, but that
61 * would require growth of the structure. That's why they are implemented
62 * as a separate hash indexed by vm_page address. Implementation lives in
63 * kern/subr_sfbuf.c. Meanwhile, most 64-bit machines have a physical map,
64 * so they don't require this hash at all, thus ignore subr_sfbuf.c.
65 *
66 * Different 32-bit architectures demand different requirements on sf_buf
67 * hash and functions. They request features in machine/vmparam.h, which
68 * enable parts of this file. They can also optionally provide helpers in
69 * machine/sf_buf.h
70 *
71 * Defines are:
72 * SFBUF This machine requires sf_buf hash.
73 * subr_sfbuf.c should be compiled.
74 * SFBUF_CPUSET This machine can perform SFB_CPUPRIVATE mappings,
75 * that do no invalidate cache on the rest of CPUs.
76 * SFBUF_NOMD This machine doesn't have machine/sf_buf.h
77 *
78 * SFBUF_MAP This machine provides its own sf_buf_map() and
79 * sf_buf_unmap().
80 * SFBUF_PROCESS_PAGE This machine provides sf_buf_process_page()
81 * function.
82 */
83
84#ifdef SFBUF
85#if defined(SMP) && defined(SFBUF_CPUSET)
86#include <sys/_cpuset.h>
87#endif
88#include <sys/queue.h>
89
90struct sf_buf {
91 LIST_ENTRY(sf_buf) list_entry; /* list of buffers */
92 TAILQ_ENTRY(sf_buf) free_entry; /* list of buffers */
93 vm_page_t m; /* currently mapped page */
94 vm_offset_t kva; /* va of mapping */
95 int ref_count; /* usage of this mapping */
96#if defined(SMP) && defined(SFBUF_CPUSET)
97 cpuset_t cpumask; /* where mapping is valid */
98#endif
99};
100#else /* ! SFBUF */
101struct sf_buf;
102#endif /* SFBUF */
103
104#ifndef SFBUF_NOMD
105#include <machine/sf_buf.h>
106#endif
107
108#ifdef SFBUF
109struct sf_buf *sf_buf_alloc(struct vm_page *, int);
110void sf_buf_free(struct sf_buf *);
111void sf_buf_ref(struct sf_buf *);
112
113static inline vm_offset_t
114sf_buf_kva(struct sf_buf *sf)
115{
116 if (PMAP_HAS_DMAP)
117 return (PHYS_TO_DMAP(VM_PAGE_TO_PHYS((vm_page_t)sf)));
118
119 return (sf->kva);
120}
121
122static inline vm_page_t
123sf_buf_page(struct sf_buf *sf)
124{
125 if (PMAP_HAS_DMAP)
126 return ((vm_page_t)sf);
127
128 return (sf->m);
129}
130
131#ifndef SFBUF_MAP
132#include <vm/pmap.h>
133
134static inline void
135sf_buf_map(struct sf_buf *sf, int flags)
136{
137
138 pmap_qenter(sf->kva, &sf->m, 1);
139}
140
141static inline int
142sf_buf_unmap(struct sf_buf *sf)
143{
144
145 return (0);
146}
147#endif /* SFBUF_MAP */
148
149#if defined(SMP) && defined(SFBUF_CPUSET)
150void sf_buf_shootdown(struct sf_buf *, int);
151#endif
152
153#ifdef SFBUF_PROCESS_PAGE
154boolean_t sf_buf_process_page(vm_page_t, void (*)(struct sf_buf *));
155#endif
156
157#else /* ! SFBUF */
158
159static inline struct sf_buf *
160sf_buf_alloc(struct vm_page *m, int pri)
161{
162
163 return ((struct sf_buf *)m);
164}
165
166static inline void
167sf_buf_free(struct sf_buf *sf)
168{
169}
170
171static inline void
172sf_buf_ref(struct sf_buf *sf)
173{
174}
175#endif /* SFBUF */
176
177/*
178 * Options to sf_buf_alloc() are specified through its flags argument. This
179 * argument's value should be the result of a bitwise or'ing of one or more
180 * of the following values.
181 */
182#define SFB_CATCH 1 /* Check signals if the allocation
183 sleeps. */
184#define SFB_CPUPRIVATE 2 /* Create a CPU private mapping. */
185#define SFB_DEFAULT 0
186#define SFB_NOWAIT 4 /* Return NULL if all bufs are used. */
187
188extern counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)];
189#define SFSTAT_ADD(name, val) \
190 counter_u64_add(sfstat[offsetof(struct sfstat, name) / sizeof(uint64_t)],\
191 (val))
192#define SFSTAT_INC(name) SFSTAT_ADD(name, 1)
193#endif /* _KERNEL */
194#endif /* !_SYS_SF_BUF_H_ */