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> | |
5f350952 JA |
14 | |
15 | #include "../fio.h" | |
2866c82d | 16 | |
34cfcdaf JA |
17 | #ifdef FIO_HAVE_SPLICE |
18 | ||
2866c82d | 19 | struct spliceio_data { |
2866c82d | 20 | int pipe[2]; |
f24254e1 | 21 | int vmsplice_to_user; |
2866c82d JA |
22 | }; |
23 | ||
2866c82d | 24 | /* |
f24254e1 JA |
25 | * vmsplice didn't use to support splicing to user space, this is the old |
26 | * variant of getting that job done. Doesn't make a lot of sense, but it | |
27 | * uses splices to move data from the source into a pipe. | |
2866c82d | 28 | */ |
f24254e1 | 29 | static int fio_splice_read_old(struct thread_data *td, struct io_u *io_u) |
2866c82d JA |
30 | { |
31 | struct spliceio_data *sd = td->io_ops->data; | |
53cdc686 | 32 | struct fio_file *f = io_u->file; |
2866c82d JA |
33 | int ret, ret2, buflen; |
34 | off_t offset; | |
35 | void *p; | |
36 | ||
37 | offset = io_u->offset; | |
cec6b55d JA |
38 | buflen = io_u->xfer_buflen; |
39 | p = io_u->xfer_buf; | |
2866c82d JA |
40 | while (buflen) { |
41 | int this_len = buflen; | |
42 | ||
43 | if (this_len > SPLICE_DEF_SIZE) | |
44 | this_len = SPLICE_DEF_SIZE; | |
45 | ||
53cdc686 | 46 | ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len, SPLICE_F_MORE); |
2866c82d JA |
47 | if (ret < 0) { |
48 | if (errno == ENODATA || errno == EAGAIN) | |
49 | continue; | |
50 | ||
b4ba5f30 | 51 | return -errno; |
2866c82d JA |
52 | } |
53 | ||
54 | buflen -= ret; | |
55 | ||
56 | while (ret) { | |
57 | ret2 = read(sd->pipe[0], p, ret); | |
58 | if (ret2 < 0) | |
b4ba5f30 | 59 | return -errno; |
2866c82d JA |
60 | |
61 | ret -= ret2; | |
62 | p += ret2; | |
63 | } | |
64 | } | |
65 | ||
cec6b55d | 66 | return io_u->xfer_buflen; |
2866c82d JA |
67 | } |
68 | ||
f24254e1 JA |
69 | /* |
70 | * We can now vmsplice into userspace, so do the transfer by splicing into | |
71 | * a pipe and vmsplicing that into userspace. | |
72 | */ | |
73 | static int fio_splice_read(struct thread_data *td, struct io_u *io_u) | |
74 | { | |
75 | struct spliceio_data *sd = td->io_ops->data; | |
76 | struct fio_file *f = io_u->file; | |
77 | struct iovec iov; | |
78 | int ret, buflen; | |
79 | off_t offset; | |
80 | void *p; | |
81 | ||
82 | offset = io_u->offset; | |
83 | buflen = io_u->xfer_buflen; | |
84 | p = io_u->xfer_buf; | |
85 | while (buflen) { | |
86 | int this_len = buflen; | |
87 | ||
88 | if (this_len > SPLICE_DEF_SIZE) | |
89 | this_len = SPLICE_DEF_SIZE; | |
90 | ||
91 | ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len, SPLICE_F_MORE); | |
92 | if (ret < 0) { | |
93 | if (errno == ENODATA || errno == EAGAIN) | |
94 | continue; | |
95 | ||
96 | return -errno; | |
97 | } | |
98 | ||
99 | buflen -= ret; | |
100 | iov.iov_base = p; | |
101 | iov.iov_len = ret; | |
102 | p += ret; | |
103 | ||
104 | while (iov.iov_len) { | |
105 | ret = vmsplice(sd->pipe[0], &iov, 1, SPLICE_F_MOVE); | |
106 | if (ret < 0) | |
107 | return -errno; | |
108 | else if (!ret) | |
109 | return -ENODATA; | |
110 | ||
111 | iov.iov_len -= ret; | |
112 | iov.iov_base += ret; | |
113 | } | |
114 | } | |
115 | ||
116 | return io_u->xfer_buflen; | |
117 | } | |
118 | ||
119 | ||
2866c82d JA |
120 | /* |
121 | * For splice writing, we can vmsplice our data buffer directly into a | |
122 | * pipe and then splice that to a file. | |
123 | */ | |
124 | static int fio_splice_write(struct thread_data *td, struct io_u *io_u) | |
125 | { | |
126 | struct spliceio_data *sd = td->io_ops->data; | |
f24254e1 JA |
127 | struct iovec iov = { |
128 | .iov_base = io_u->xfer_buf, | |
129 | .iov_len = io_u->xfer_buflen, | |
2866c82d JA |
130 | }; |
131 | struct pollfd pfd = { .fd = sd->pipe[1], .events = POLLOUT, }; | |
53cdc686 | 132 | struct fio_file *f = io_u->file; |
2866c82d JA |
133 | off_t off = io_u->offset; |
134 | int ret, ret2; | |
135 | ||
f24254e1 | 136 | while (iov.iov_len) { |
2866c82d JA |
137 | if (poll(&pfd, 1, -1) < 0) |
138 | return errno; | |
139 | ||
f24254e1 | 140 | ret = vmsplice(sd->pipe[1], &iov, 1, SPLICE_F_NONBLOCK); |
2866c82d | 141 | if (ret < 0) |
b4ba5f30 | 142 | return -errno; |
2866c82d | 143 | |
f24254e1 JA |
144 | iov.iov_len -= ret; |
145 | iov.iov_base += ret; | |
2866c82d JA |
146 | |
147 | while (ret) { | |
53cdc686 | 148 | ret2 = splice(sd->pipe[0], NULL, f->fd, &off, ret, 0); |
2866c82d | 149 | if (ret2 < 0) |
b4ba5f30 | 150 | return -errno; |
2866c82d JA |
151 | |
152 | ret -= ret2; | |
153 | } | |
154 | } | |
155 | ||
cec6b55d | 156 | return io_u->xfer_buflen; |
2866c82d JA |
157 | } |
158 | ||
159 | static int fio_spliceio_queue(struct thread_data *td, struct io_u *io_u) | |
160 | { | |
f24254e1 | 161 | struct spliceio_data *sd = td->io_ops->data; |
cec6b55d | 162 | int ret; |
2866c82d | 163 | |
f24254e1 JA |
164 | if (io_u->ddir == DDIR_READ) { |
165 | if (sd->vmsplice_to_user) | |
166 | ret = fio_splice_read(td, io_u); | |
167 | else | |
168 | ret = fio_splice_read_old(td, io_u); | |
169 | } else if (io_u->ddir == DDIR_WRITE) | |
2866c82d | 170 | ret = fio_splice_write(td, io_u); |
87dc1ab1 JA |
171 | else |
172 | ret = fsync(io_u->file->fd); | |
2866c82d | 173 | |
cec6b55d | 174 | if (ret != (int) io_u->xfer_buflen) { |
22819ec2 | 175 | if (ret >= 0) { |
cec6b55d JA |
176 | io_u->resid = io_u->xfer_buflen - ret; |
177 | io_u->error = 0; | |
36167d82 | 178 | return FIO_Q_COMPLETED; |
2866c82d JA |
179 | } else |
180 | io_u->error = errno; | |
181 | } | |
182 | ||
36167d82 | 183 | if (io_u->error) |
e1161c32 | 184 | td_verror(td, io_u->error, "xfer"); |
2866c82d | 185 | |
36167d82 | 186 | return FIO_Q_COMPLETED; |
2866c82d JA |
187 | } |
188 | ||
189 | static void fio_spliceio_cleanup(struct thread_data *td) | |
190 | { | |
191 | struct spliceio_data *sd = td->io_ops->data; | |
192 | ||
193 | if (sd) { | |
194 | close(sd->pipe[0]); | |
195 | close(sd->pipe[1]); | |
196 | free(sd); | |
197 | td->io_ops->data = NULL; | |
198 | } | |
199 | } | |
200 | ||
201 | static int fio_spliceio_init(struct thread_data *td) | |
202 | { | |
203 | struct spliceio_data *sd = malloc(sizeof(*sd)); | |
204 | ||
2866c82d | 205 | if (pipe(sd->pipe) < 0) { |
e1161c32 | 206 | td_verror(td, errno, "pipe"); |
2866c82d JA |
207 | free(sd); |
208 | return 1; | |
209 | } | |
210 | ||
f24254e1 JA |
211 | /* |
212 | * need some check for enabling this, for now just leave it disabled | |
213 | */ | |
214 | sd->vmsplice_to_user = 0; | |
215 | ||
2866c82d JA |
216 | td->io_ops->data = sd; |
217 | return 0; | |
218 | } | |
219 | ||
5f350952 | 220 | static struct ioengine_ops ioengine = { |
2866c82d JA |
221 | .name = "splice", |
222 | .version = FIO_IOOPS_VERSION, | |
223 | .init = fio_spliceio_init, | |
224 | .queue = fio_spliceio_queue, | |
2866c82d | 225 | .cleanup = fio_spliceio_cleanup, |
b5af8293 JA |
226 | .open_file = generic_open_file, |
227 | .close_file = generic_close_file, | |
2866c82d JA |
228 | .flags = FIO_SYNCIO, |
229 | }; | |
34cfcdaf JA |
230 | |
231 | #else /* FIO_HAVE_SPLICE */ | |
232 | ||
233 | /* | |
234 | * When we have a proper configure system in place, we simply wont build | |
235 | * and install this io engine. For now install a crippled version that | |
236 | * just complains and fails to load. | |
237 | */ | |
238 | static int fio_spliceio_init(struct thread_data fio_unused *td) | |
239 | { | |
240 | fprintf(stderr, "fio: splice not available\n"); | |
241 | return 1; | |
242 | } | |
243 | ||
5f350952 | 244 | static struct ioengine_ops ioengine = { |
34cfcdaf JA |
245 | .name = "splice", |
246 | .version = FIO_IOOPS_VERSION, | |
247 | .init = fio_spliceio_init, | |
248 | }; | |
249 | ||
250 | #endif | |
5f350952 JA |
251 | |
252 | static void fio_init fio_spliceio_register(void) | |
253 | { | |
254 | register_ioengine(&ioengine); | |
255 | } | |
256 | ||
257 | static void fio_exit fio_spliceio_unregister(void) | |
258 | { | |
259 | unregister_ioengine(&ioengine); | |
260 | } |