Commit | Line | Data |
---|---|---|
2866c82d | 1 | /* |
da751ca9 JA |
2 | * splice engine |
3 | * | |
4 | * IO engine that transfers data by doing splices to/from pipes and | |
5 | * the files. | |
2866c82d JA |
6 | * |
7 | */ | |
8 | #include <stdio.h> | |
9 | #include <stdlib.h> | |
10 | #include <unistd.h> | |
11 | #include <errno.h> | |
12 | #include <assert.h> | |
13 | #include <sys/poll.h> | |
81887d5d | 14 | #include <sys/mman.h> |
5f350952 JA |
15 | |
16 | #include "../fio.h" | |
2866c82d | 17 | |
34cfcdaf JA |
18 | #ifdef FIO_HAVE_SPLICE |
19 | ||
2866c82d | 20 | struct spliceio_data { |
2866c82d | 21 | int pipe[2]; |
f24254e1 | 22 | int vmsplice_to_user; |
8b850243 | 23 | int vmsplice_to_user_map; |
2866c82d JA |
24 | }; |
25 | ||
2866c82d | 26 | /* |
f24254e1 JA |
27 | * vmsplice didn't use to support splicing to user space, this is the old |
28 | * variant of getting that job done. Doesn't make a lot of sense, but it | |
29 | * uses splices to move data from the source into a pipe. | |
2866c82d | 30 | */ |
f24254e1 | 31 | static int fio_splice_read_old(struct thread_data *td, struct io_u *io_u) |
2866c82d JA |
32 | { |
33 | struct spliceio_data *sd = td->io_ops->data; | |
53cdc686 | 34 | struct fio_file *f = io_u->file; |
2866c82d JA |
35 | int ret, ret2, buflen; |
36 | off_t offset; | |
37 | void *p; | |
38 | ||
39 | offset = io_u->offset; | |
cec6b55d JA |
40 | buflen = io_u->xfer_buflen; |
41 | p = io_u->xfer_buf; | |
2866c82d JA |
42 | while (buflen) { |
43 | int this_len = buflen; | |
44 | ||
45 | if (this_len > SPLICE_DEF_SIZE) | |
46 | this_len = SPLICE_DEF_SIZE; | |
47 | ||
53cdc686 | 48 | ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len, SPLICE_F_MORE); |
2866c82d JA |
49 | if (ret < 0) { |
50 | if (errno == ENODATA || errno == EAGAIN) | |
51 | continue; | |
52 | ||
b4ba5f30 | 53 | return -errno; |
2866c82d JA |
54 | } |
55 | ||
56 | buflen -= ret; | |
57 | ||
58 | while (ret) { | |
59 | ret2 = read(sd->pipe[0], p, ret); | |
60 | if (ret2 < 0) | |
b4ba5f30 | 61 | return -errno; |
2866c82d JA |
62 | |
63 | ret -= ret2; | |
64 | p += ret2; | |
65 | } | |
66 | } | |
67 | ||
cec6b55d | 68 | return io_u->xfer_buflen; |
2866c82d JA |
69 | } |
70 | ||
f24254e1 JA |
71 | /* |
72 | * We can now vmsplice into userspace, so do the transfer by splicing into | |
73 | * a pipe and vmsplicing that into userspace. | |
74 | */ | |
75 | static int fio_splice_read(struct thread_data *td, struct io_u *io_u) | |
76 | { | |
77 | struct spliceio_data *sd = td->io_ops->data; | |
78 | struct fio_file *f = io_u->file; | |
79 | struct iovec iov; | |
8b850243 | 80 | int ret , buflen, mmap_len; |
f24254e1 | 81 | off_t offset; |
81887d5d | 82 | void *p, *map; |
f24254e1 | 83 | |
8b850243 JA |
84 | restart: |
85 | ret = 0; | |
f24254e1 | 86 | offset = io_u->offset; |
81887d5d JA |
87 | mmap_len = buflen = io_u->xfer_buflen; |
88 | ||
8b850243 JA |
89 | if (sd->vmsplice_to_user_map) { |
90 | map = mmap(io_u->xfer_buf, buflen, PROT_READ, MAP_PRIVATE|OS_MAP_ANON, 0, 0); | |
91 | if (map == MAP_FAILED) { | |
92 | td_verror(td, errno, "mmap io_u"); | |
93 | return -1; | |
94 | } | |
95 | ||
96 | p = map; | |
97 | } else { | |
98 | map = NULL; | |
99 | p = io_u->xfer_buf; | |
81887d5d JA |
100 | } |
101 | ||
f24254e1 JA |
102 | while (buflen) { |
103 | int this_len = buflen; | |
81887d5d | 104 | int flags = 0; |
f24254e1 | 105 | |
81887d5d | 106 | if (this_len > SPLICE_DEF_SIZE) { |
f24254e1 | 107 | this_len = SPLICE_DEF_SIZE; |
81887d5d JA |
108 | flags = SPLICE_F_MORE; |
109 | } | |
f24254e1 | 110 | |
81887d5d | 111 | ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len,flags); |
f24254e1 JA |
112 | if (ret < 0) { |
113 | if (errno == ENODATA || errno == EAGAIN) | |
114 | continue; | |
115 | ||
81887d5d JA |
116 | td_verror(td, errno, "splice-from-fd"); |
117 | break; | |
f24254e1 JA |
118 | } |
119 | ||
120 | buflen -= ret; | |
121 | iov.iov_base = p; | |
122 | iov.iov_len = ret; | |
123 | p += ret; | |
124 | ||
125 | while (iov.iov_len) { | |
126 | ret = vmsplice(sd->pipe[0], &iov, 1, SPLICE_F_MOVE); | |
81887d5d | 127 | if (ret < 0) { |
8b850243 JA |
128 | if (errno == EFAULT && sd->vmsplice_to_user_map) { |
129 | sd->vmsplice_to_user_map = 0; | |
130 | munmap(map, mmap_len); | |
131 | goto restart; | |
132 | } | |
3a6d267d JA |
133 | if (errno == EBADF) { |
134 | ret = -EBADF; | |
135 | break; | |
136 | } | |
81887d5d JA |
137 | td_verror(td, errno, "vmsplice"); |
138 | break; | |
139 | } else if (!ret) { | |
140 | td_verror(td, ENODATA, "vmsplice"); | |
141 | ret = -1; | |
142 | break; | |
143 | } | |
f24254e1 JA |
144 | |
145 | iov.iov_len -= ret; | |
146 | iov.iov_base += ret; | |
147 | } | |
81887d5d JA |
148 | if (ret < 0) |
149 | break; | |
150 | } | |
151 | ||
8b850243 | 152 | if (sd->vmsplice_to_user_map && munmap(map, mmap_len) < 0) { |
81887d5d JA |
153 | td_verror(td, errno, "munnap io_u"); |
154 | return -1; | |
f24254e1 | 155 | } |
81887d5d JA |
156 | if (ret < 0) |
157 | return ret; | |
f24254e1 JA |
158 | |
159 | return io_u->xfer_buflen; | |
160 | } | |
161 | ||
2866c82d JA |
162 | /* |
163 | * For splice writing, we can vmsplice our data buffer directly into a | |
164 | * pipe and then splice that to a file. | |
165 | */ | |
166 | static int fio_splice_write(struct thread_data *td, struct io_u *io_u) | |
167 | { | |
168 | struct spliceio_data *sd = td->io_ops->data; | |
f24254e1 JA |
169 | struct iovec iov = { |
170 | .iov_base = io_u->xfer_buf, | |
171 | .iov_len = io_u->xfer_buflen, | |
2866c82d JA |
172 | }; |
173 | struct pollfd pfd = { .fd = sd->pipe[1], .events = POLLOUT, }; | |
53cdc686 | 174 | struct fio_file *f = io_u->file; |
2866c82d JA |
175 | off_t off = io_u->offset; |
176 | int ret, ret2; | |
177 | ||
f24254e1 | 178 | while (iov.iov_len) { |
2866c82d JA |
179 | if (poll(&pfd, 1, -1) < 0) |
180 | return errno; | |
181 | ||
f24254e1 | 182 | ret = vmsplice(sd->pipe[1], &iov, 1, SPLICE_F_NONBLOCK); |
2866c82d | 183 | if (ret < 0) |
b4ba5f30 | 184 | return -errno; |
2866c82d | 185 | |
f24254e1 JA |
186 | iov.iov_len -= ret; |
187 | iov.iov_base += ret; | |
2866c82d JA |
188 | |
189 | while (ret) { | |
53cdc686 | 190 | ret2 = splice(sd->pipe[0], NULL, f->fd, &off, ret, 0); |
2866c82d | 191 | if (ret2 < 0) |
b4ba5f30 | 192 | return -errno; |
2866c82d JA |
193 | |
194 | ret -= ret2; | |
195 | } | |
196 | } | |
197 | ||
cec6b55d | 198 | return io_u->xfer_buflen; |
2866c82d JA |
199 | } |
200 | ||
201 | static int fio_spliceio_queue(struct thread_data *td, struct io_u *io_u) | |
202 | { | |
f24254e1 | 203 | struct spliceio_data *sd = td->io_ops->data; |
cec6b55d | 204 | int ret; |
2866c82d | 205 | |
7101d9c2 JA |
206 | fio_ro_check(td, io_u); |
207 | ||
f24254e1 | 208 | if (io_u->ddir == DDIR_READ) { |
43688575 | 209 | if (sd->vmsplice_to_user) { |
f24254e1 | 210 | ret = fio_splice_read(td, io_u); |
43688575 JA |
211 | /* |
212 | * This kernel doesn't support vmsplice to user | |
213 | * space. Reset the vmsplice_to_user flag, so that | |
214 | * we retry below and don't hit this path again. | |
215 | */ | |
216 | if (ret == -EBADF) | |
217 | sd->vmsplice_to_user = 0; | |
218 | } | |
219 | if (!sd->vmsplice_to_user) | |
f24254e1 JA |
220 | ret = fio_splice_read_old(td, io_u); |
221 | } else if (io_u->ddir == DDIR_WRITE) | |
2866c82d | 222 | ret = fio_splice_write(td, io_u); |
87dc1ab1 JA |
223 | else |
224 | ret = fsync(io_u->file->fd); | |
2866c82d | 225 | |
cec6b55d | 226 | if (ret != (int) io_u->xfer_buflen) { |
22819ec2 | 227 | if (ret >= 0) { |
cec6b55d JA |
228 | io_u->resid = io_u->xfer_buflen - ret; |
229 | io_u->error = 0; | |
36167d82 | 230 | return FIO_Q_COMPLETED; |
2866c82d JA |
231 | } else |
232 | io_u->error = errno; | |
233 | } | |
234 | ||
36167d82 | 235 | if (io_u->error) |
e1161c32 | 236 | td_verror(td, io_u->error, "xfer"); |
2866c82d | 237 | |
36167d82 | 238 | return FIO_Q_COMPLETED; |
2866c82d JA |
239 | } |
240 | ||
241 | static void fio_spliceio_cleanup(struct thread_data *td) | |
242 | { | |
243 | struct spliceio_data *sd = td->io_ops->data; | |
244 | ||
245 | if (sd) { | |
246 | close(sd->pipe[0]); | |
247 | close(sd->pipe[1]); | |
248 | free(sd); | |
249 | td->io_ops->data = NULL; | |
250 | } | |
251 | } | |
252 | ||
253 | static int fio_spliceio_init(struct thread_data *td) | |
254 | { | |
255 | struct spliceio_data *sd = malloc(sizeof(*sd)); | |
256 | ||
2866c82d | 257 | if (pipe(sd->pipe) < 0) { |
e1161c32 | 258 | td_verror(td, errno, "pipe"); |
2866c82d JA |
259 | free(sd); |
260 | return 1; | |
261 | } | |
262 | ||
f24254e1 | 263 | /* |
43688575 | 264 | * Assume this work, we'll reset this if it doesn't |
f24254e1 | 265 | */ |
43688575 | 266 | sd->vmsplice_to_user = 1; |
f24254e1 | 267 | |
8b850243 JA |
268 | /* |
269 | * Works with "real" vmsplice to user, eg mapping pages directly. | |
270 | * Reset if we fail. | |
271 | */ | |
272 | sd->vmsplice_to_user_map = 1; | |
273 | ||
81887d5d JA |
274 | /* |
275 | * And if vmsplice_to_user works, we definitely need aligned | |
276 | * buffers. Just set ->odirect to force that. | |
277 | */ | |
278 | if (td_read(td)) | |
279 | td->o.odirect = 1; | |
280 | ||
2866c82d JA |
281 | td->io_ops->data = sd; |
282 | return 0; | |
283 | } | |
284 | ||
5f350952 | 285 | static struct ioengine_ops ioengine = { |
2866c82d JA |
286 | .name = "splice", |
287 | .version = FIO_IOOPS_VERSION, | |
288 | .init = fio_spliceio_init, | |
289 | .queue = fio_spliceio_queue, | |
2866c82d | 290 | .cleanup = fio_spliceio_cleanup, |
b5af8293 JA |
291 | .open_file = generic_open_file, |
292 | .close_file = generic_close_file, | |
2866c82d JA |
293 | .flags = FIO_SYNCIO, |
294 | }; | |
34cfcdaf JA |
295 | |
296 | #else /* FIO_HAVE_SPLICE */ | |
297 | ||
298 | /* | |
299 | * When we have a proper configure system in place, we simply wont build | |
300 | * and install this io engine. For now install a crippled version that | |
301 | * just complains and fails to load. | |
302 | */ | |
303 | static int fio_spliceio_init(struct thread_data fio_unused *td) | |
304 | { | |
305 | fprintf(stderr, "fio: splice not available\n"); | |
306 | return 1; | |
307 | } | |
308 | ||
5f350952 | 309 | static struct ioengine_ops ioengine = { |
34cfcdaf JA |
310 | .name = "splice", |
311 | .version = FIO_IOOPS_VERSION, | |
312 | .init = fio_spliceio_init, | |
313 | }; | |
314 | ||
315 | #endif | |
5f350952 JA |
316 | |
317 | static void fio_init fio_spliceio_register(void) | |
318 | { | |
319 | register_ioengine(&ioengine); | |
320 | } | |
321 | ||
322 | static void fio_exit fio_spliceio_unregister(void) | |
323 | { | |
324 | unregister_ioengine(&ioengine); | |
325 | } |