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 | 84 | ret = 0; |
f24254e1 | 85 | offset = io_u->offset; |
81887d5d JA |
86 | mmap_len = buflen = io_u->xfer_buflen; |
87 | ||
8b850243 JA |
88 | if (sd->vmsplice_to_user_map) { |
89 | map = mmap(io_u->xfer_buf, buflen, PROT_READ, MAP_PRIVATE|OS_MAP_ANON, 0, 0); | |
90 | if (map == MAP_FAILED) { | |
91 | td_verror(td, errno, "mmap io_u"); | |
92 | return -1; | |
93 | } | |
94 | ||
95 | p = map; | |
96 | } else { | |
97 | map = NULL; | |
98 | p = io_u->xfer_buf; | |
81887d5d JA |
99 | } |
100 | ||
f24254e1 JA |
101 | while (buflen) { |
102 | int this_len = buflen; | |
81887d5d | 103 | int flags = 0; |
f24254e1 | 104 | |
81887d5d | 105 | if (this_len > SPLICE_DEF_SIZE) { |
f24254e1 | 106 | this_len = SPLICE_DEF_SIZE; |
81887d5d JA |
107 | flags = SPLICE_F_MORE; |
108 | } | |
f24254e1 | 109 | |
81887d5d | 110 | ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len,flags); |
f24254e1 JA |
111 | if (ret < 0) { |
112 | if (errno == ENODATA || errno == EAGAIN) | |
113 | continue; | |
114 | ||
81887d5d JA |
115 | td_verror(td, errno, "splice-from-fd"); |
116 | break; | |
f24254e1 JA |
117 | } |
118 | ||
119 | buflen -= ret; | |
120 | iov.iov_base = p; | |
121 | iov.iov_len = ret; | |
f24254e1 JA |
122 | |
123 | while (iov.iov_len) { | |
124 | ret = vmsplice(sd->pipe[0], &iov, 1, SPLICE_F_MOVE); | |
81887d5d | 125 | if (ret < 0) { |
cd98801f JA |
126 | if (errno == EFAULT && |
127 | sd->vmsplice_to_user_map) { | |
8b850243 JA |
128 | sd->vmsplice_to_user_map = 0; |
129 | munmap(map, mmap_len); | |
cd98801f JA |
130 | map = NULL; |
131 | p = io_u->xfer_buf; | |
132 | iov.iov_base = p; | |
133 | continue; | |
8b850243 | 134 | } |
3a6d267d JA |
135 | if (errno == EBADF) { |
136 | ret = -EBADF; | |
137 | break; | |
138 | } | |
81887d5d JA |
139 | td_verror(td, errno, "vmsplice"); |
140 | break; | |
141 | } else if (!ret) { | |
142 | td_verror(td, ENODATA, "vmsplice"); | |
143 | ret = -1; | |
144 | break; | |
145 | } | |
f24254e1 JA |
146 | |
147 | iov.iov_len -= ret; | |
148 | iov.iov_base += ret; | |
cd98801f | 149 | p += ret; |
f24254e1 | 150 | } |
81887d5d JA |
151 | if (ret < 0) |
152 | break; | |
153 | } | |
154 | ||
8b850243 | 155 | if (sd->vmsplice_to_user_map && munmap(map, mmap_len) < 0) { |
81887d5d JA |
156 | td_verror(td, errno, "munnap io_u"); |
157 | return -1; | |
f24254e1 | 158 | } |
81887d5d JA |
159 | if (ret < 0) |
160 | return ret; | |
f24254e1 JA |
161 | |
162 | return io_u->xfer_buflen; | |
163 | } | |
164 | ||
2866c82d JA |
165 | /* |
166 | * For splice writing, we can vmsplice our data buffer directly into a | |
167 | * pipe and then splice that to a file. | |
168 | */ | |
169 | static int fio_splice_write(struct thread_data *td, struct io_u *io_u) | |
170 | { | |
171 | struct spliceio_data *sd = td->io_ops->data; | |
f24254e1 JA |
172 | struct iovec iov = { |
173 | .iov_base = io_u->xfer_buf, | |
174 | .iov_len = io_u->xfer_buflen, | |
2866c82d JA |
175 | }; |
176 | struct pollfd pfd = { .fd = sd->pipe[1], .events = POLLOUT, }; | |
53cdc686 | 177 | struct fio_file *f = io_u->file; |
2866c82d JA |
178 | off_t off = io_u->offset; |
179 | int ret, ret2; | |
180 | ||
f24254e1 | 181 | while (iov.iov_len) { |
2866c82d JA |
182 | if (poll(&pfd, 1, -1) < 0) |
183 | return errno; | |
184 | ||
f24254e1 | 185 | ret = vmsplice(sd->pipe[1], &iov, 1, SPLICE_F_NONBLOCK); |
2866c82d | 186 | if (ret < 0) |
b4ba5f30 | 187 | return -errno; |
2866c82d | 188 | |
f24254e1 JA |
189 | iov.iov_len -= ret; |
190 | iov.iov_base += ret; | |
2866c82d JA |
191 | |
192 | while (ret) { | |
53cdc686 | 193 | ret2 = splice(sd->pipe[0], NULL, f->fd, &off, ret, 0); |
2866c82d | 194 | if (ret2 < 0) |
b4ba5f30 | 195 | return -errno; |
2866c82d JA |
196 | |
197 | ret -= ret2; | |
198 | } | |
199 | } | |
200 | ||
cec6b55d | 201 | return io_u->xfer_buflen; |
2866c82d JA |
202 | } |
203 | ||
204 | static int fio_spliceio_queue(struct thread_data *td, struct io_u *io_u) | |
205 | { | |
f24254e1 | 206 | struct spliceio_data *sd = td->io_ops->data; |
f3f552b9 | 207 | int uninitialized_var(ret); |
2866c82d | 208 | |
7101d9c2 JA |
209 | fio_ro_check(td, io_u); |
210 | ||
f24254e1 | 211 | if (io_u->ddir == DDIR_READ) { |
43688575 | 212 | if (sd->vmsplice_to_user) { |
f24254e1 | 213 | ret = fio_splice_read(td, io_u); |
43688575 JA |
214 | /* |
215 | * This kernel doesn't support vmsplice to user | |
216 | * space. Reset the vmsplice_to_user flag, so that | |
217 | * we retry below and don't hit this path again. | |
218 | */ | |
219 | if (ret == -EBADF) | |
220 | sd->vmsplice_to_user = 0; | |
221 | } | |
222 | if (!sd->vmsplice_to_user) | |
f24254e1 JA |
223 | ret = fio_splice_read_old(td, io_u); |
224 | } else if (io_u->ddir == DDIR_WRITE) | |
2866c82d | 225 | ret = fio_splice_write(td, io_u); |
87dc1ab1 JA |
226 | else |
227 | ret = fsync(io_u->file->fd); | |
2866c82d | 228 | |
cec6b55d | 229 | if (ret != (int) io_u->xfer_buflen) { |
22819ec2 | 230 | if (ret >= 0) { |
cec6b55d JA |
231 | io_u->resid = io_u->xfer_buflen - ret; |
232 | io_u->error = 0; | |
36167d82 | 233 | return FIO_Q_COMPLETED; |
2866c82d JA |
234 | } else |
235 | io_u->error = errno; | |
236 | } | |
237 | ||
0aa417a9 | 238 | if (io_u->error) { |
e1161c32 | 239 | td_verror(td, io_u->error, "xfer"); |
0aa417a9 JA |
240 | if (io_u->error == EINVAL) |
241 | log_err("fio: looks like splice doesn't work on this" | |
242 | " file system\n"); | |
243 | } | |
2866c82d | 244 | |
36167d82 | 245 | return FIO_Q_COMPLETED; |
2866c82d JA |
246 | } |
247 | ||
248 | static void fio_spliceio_cleanup(struct thread_data *td) | |
249 | { | |
250 | struct spliceio_data *sd = td->io_ops->data; | |
251 | ||
252 | if (sd) { | |
253 | close(sd->pipe[0]); | |
254 | close(sd->pipe[1]); | |
255 | free(sd); | |
2866c82d JA |
256 | } |
257 | } | |
258 | ||
259 | static int fio_spliceio_init(struct thread_data *td) | |
260 | { | |
261 | struct spliceio_data *sd = malloc(sizeof(*sd)); | |
262 | ||
2866c82d | 263 | if (pipe(sd->pipe) < 0) { |
e1161c32 | 264 | td_verror(td, errno, "pipe"); |
2866c82d JA |
265 | free(sd); |
266 | return 1; | |
267 | } | |
268 | ||
f24254e1 | 269 | /* |
43688575 | 270 | * Assume this work, we'll reset this if it doesn't |
f24254e1 | 271 | */ |
43688575 | 272 | sd->vmsplice_to_user = 1; |
f24254e1 | 273 | |
8b850243 JA |
274 | /* |
275 | * Works with "real" vmsplice to user, eg mapping pages directly. | |
276 | * Reset if we fail. | |
277 | */ | |
278 | sd->vmsplice_to_user_map = 1; | |
279 | ||
81887d5d JA |
280 | /* |
281 | * And if vmsplice_to_user works, we definitely need aligned | |
282 | * buffers. Just set ->odirect to force that. | |
283 | */ | |
284 | if (td_read(td)) | |
285 | td->o.odirect = 1; | |
286 | ||
2866c82d JA |
287 | td->io_ops->data = sd; |
288 | return 0; | |
289 | } | |
290 | ||
5f350952 | 291 | static struct ioengine_ops ioengine = { |
2866c82d JA |
292 | .name = "splice", |
293 | .version = FIO_IOOPS_VERSION, | |
294 | .init = fio_spliceio_init, | |
295 | .queue = fio_spliceio_queue, | |
2866c82d | 296 | .cleanup = fio_spliceio_cleanup, |
b5af8293 JA |
297 | .open_file = generic_open_file, |
298 | .close_file = generic_close_file, | |
df9c26b1 | 299 | .get_file_size = generic_get_file_size, |
9c0d2241 | 300 | .flags = FIO_SYNCIO | FIO_PIPEIO, |
2866c82d | 301 | }; |
34cfcdaf JA |
302 | |
303 | #else /* FIO_HAVE_SPLICE */ | |
304 | ||
305 | /* | |
306 | * When we have a proper configure system in place, we simply wont build | |
307 | * and install this io engine. For now install a crippled version that | |
308 | * just complains and fails to load. | |
309 | */ | |
310 | static int fio_spliceio_init(struct thread_data fio_unused *td) | |
311 | { | |
312 | fprintf(stderr, "fio: splice not available\n"); | |
313 | return 1; | |
314 | } | |
315 | ||
5f350952 | 316 | static struct ioengine_ops ioengine = { |
34cfcdaf JA |
317 | .name = "splice", |
318 | .version = FIO_IOOPS_VERSION, | |
319 | .init = fio_spliceio_init, | |
320 | }; | |
321 | ||
322 | #endif | |
5f350952 JA |
323 | |
324 | static void fio_init fio_spliceio_register(void) | |
325 | { | |
326 | register_ioengine(&ioengine); | |
327 | } | |
328 | ||
329 | static void fio_exit fio_spliceio_unregister(void) | |
330 | { | |
331 | unregister_ioengine(&ioengine); | |
332 | } |