Commit | Line | Data |
---|---|---|
75e5584c | 1 | /* |
ba180fd4 | 2 | * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
75e5584c JD |
3 | * Licensed under the GPL |
4 | */ | |
5 | ||
75e5584c | 6 | #include <unistd.h> |
ba180fd4 | 7 | #include <sched.h> |
75e5584c JD |
8 | #include <signal.h> |
9 | #include <errno.h> | |
ba180fd4 JD |
10 | #include <sys/time.h> |
11 | #include <asm/unistd.h> | |
75e5584c JD |
12 | #include "aio.h" |
13 | #include "init.h" | |
edea1385 | 14 | #include "kern_util.h" |
ba180fd4 | 15 | #include "os.h" |
75e5584c | 16 | |
91acb21f | 17 | struct aio_thread_req { |
d50084a2 JD |
18 | enum aio_type type; |
19 | int io_fd; | |
20 | unsigned long long offset; | |
21 | char *buf; | |
22 | int len; | |
23 | struct aio_context *aio; | |
91acb21f JD |
24 | }; |
25 | ||
75e5584c JD |
26 | #if defined(HAVE_AIO_ABI) |
27 | #include <linux/aio_abi.h> | |
28 | ||
ba180fd4 JD |
29 | /* |
30 | * If we have the headers, we are going to build with AIO enabled. | |
75e5584c JD |
31 | * If we don't have aio in libc, we define the necessary stubs here. |
32 | */ | |
33 | ||
34 | #if !defined(HAVE_AIO_LIBC) | |
35 | ||
36 | static long io_setup(int n, aio_context_t *ctxp) | |
37 | { | |
d50084a2 | 38 | return syscall(__NR_io_setup, n, ctxp); |
75e5584c JD |
39 | } |
40 | ||
41 | static long io_submit(aio_context_t ctx, long nr, struct iocb **iocbpp) | |
42 | { | |
d50084a2 | 43 | return syscall(__NR_io_submit, ctx, nr, iocbpp); |
75e5584c JD |
44 | } |
45 | ||
46 | static long io_getevents(aio_context_t ctx_id, long min_nr, long nr, | |
d50084a2 | 47 | struct io_event *events, struct timespec *timeout) |
75e5584c | 48 | { |
d50084a2 | 49 | return syscall(__NR_io_getevents, ctx_id, min_nr, nr, events, timeout); |
75e5584c JD |
50 | } |
51 | ||
52 | #endif | |
53 | ||
ba180fd4 JD |
54 | /* |
55 | * The AIO_MMAP cases force the mmapped page into memory here | |
75e5584c JD |
56 | * rather than in whatever place first touches the data. I used |
57 | * to do this by touching the page, but that's delicate because | |
58 | * gcc is prone to optimizing that away. So, what's done here | |
59 | * is we read from the descriptor from which the page was | |
60 | * mapped. The caller is required to pass an offset which is | |
61 | * inside the page that was mapped. Thus, when the read | |
62 | * returns, we know that the page is in the page cache, and | |
63 | * that it now backs the mmapped area. | |
64 | */ | |
65 | ||
91acb21f | 66 | static int do_aio(aio_context_t ctx, enum aio_type type, int fd, char *buf, |
d50084a2 | 67 | int len, unsigned long long offset, struct aio_context *aio) |
75e5584c | 68 | { |
da3e30e7 JD |
69 | struct iocb *iocbp = & ((struct iocb) { |
70 | .aio_data = (unsigned long) aio, | |
71 | .aio_fildes = fd, | |
72 | .aio_buf = (unsigned long) buf, | |
73 | .aio_nbytes = len, | |
74 | .aio_offset = offset | |
75 | }); | |
d50084a2 | 76 | char c; |
da3e30e7 JD |
77 | |
78 | switch (type) { | |
d50084a2 | 79 | case AIO_READ: |
da3e30e7 | 80 | iocbp->aio_lio_opcode = IOCB_CMD_PREAD; |
d50084a2 JD |
81 | break; |
82 | case AIO_WRITE: | |
da3e30e7 | 83 | iocbp->aio_lio_opcode = IOCB_CMD_PWRITE; |
d50084a2 JD |
84 | break; |
85 | case AIO_MMAP: | |
da3e30e7 JD |
86 | iocbp->aio_lio_opcode = IOCB_CMD_PREAD; |
87 | iocbp->aio_buf = (unsigned long) &c; | |
88 | iocbp->aio_nbytes = sizeof(c); | |
d50084a2 JD |
89 | break; |
90 | default: | |
da3e30e7 JD |
91 | printk(UM_KERN_ERR "Bogus op in do_aio - %d\n", type); |
92 | return -EINVAL; | |
d50084a2 JD |
93 | } |
94 | ||
da3e30e7 | 95 | return (io_submit(ctx, 1, &iocbp) > 0) ? 0 : -errno; |
75e5584c JD |
96 | } |
97 | ||
9683da91 | 98 | /* Initialized in an initcall and unchanged thereafter */ |
75e5584c JD |
99 | static aio_context_t ctx = 0; |
100 | ||
101 | static int aio_thread(void *arg) | |
102 | { | |
d50084a2 JD |
103 | struct aio_thread_reply reply; |
104 | struct io_event event; | |
105 | int err, n, reply_fd; | |
106 | ||
107 | signal(SIGWINCH, SIG_IGN); | |
108 | ||
ba180fd4 | 109 | while (1) { |
d50084a2 | 110 | n = io_getevents(ctx, 1, 1, &event, NULL); |
ba180fd4 JD |
111 | if (n < 0) { |
112 | if (errno == EINTR) | |
d50084a2 | 113 | continue; |
ba180fd4 | 114 | printk(UM_KERN_ERR "aio_thread - io_getevents failed, " |
d50084a2 JD |
115 | "errno = %d\n", errno); |
116 | } | |
117 | else { | |
118 | reply = ((struct aio_thread_reply) | |
119 | { .data = (void *) (long) event.data, | |
120 | .err = event.res }); | |
91acb21f | 121 | reply_fd = ((struct aio_context *) reply.data)->reply_fd; |
a61f334f | 122 | err = write(reply_fd, &reply, sizeof(reply)); |
ba180fd4 JD |
123 | if (err != sizeof(reply)) |
124 | printk(UM_KERN_ERR "aio_thread - write failed, " | |
125 | "fd = %d, err = %d\n", reply_fd, errno); | |
d50084a2 JD |
126 | } |
127 | } | |
128 | return 0; | |
75e5584c JD |
129 | } |
130 | ||
131 | #endif | |
132 | ||
91acb21f | 133 | static int do_not_aio(struct aio_thread_req *req) |
75e5584c | 134 | { |
d50084a2 | 135 | char c; |
ef0470c0 | 136 | unsigned long long actual; |
a61f334f | 137 | int n; |
d50084a2 | 138 | |
ef0470c0 | 139 | actual = lseek64(req->io_fd, req->offset, SEEK_SET); |
ba180fd4 | 140 | if (actual != req->offset) |
ef0470c0 JD |
141 | return -errno; |
142 | ||
5134d8fe | 143 | switch (req->type) { |
d50084a2 | 144 | case AIO_READ: |
a61f334f | 145 | n = read(req->io_fd, req->buf, req->len); |
d50084a2 JD |
146 | break; |
147 | case AIO_WRITE: | |
a61f334f | 148 | n = write(req->io_fd, req->buf, req->len); |
d50084a2 JD |
149 | break; |
150 | case AIO_MMAP: | |
a61f334f | 151 | n = read(req->io_fd, &c, sizeof(c)); |
d50084a2 JD |
152 | break; |
153 | default: | |
ba180fd4 JD |
154 | printk(UM_KERN_ERR "do_not_aio - bad request type : %d\n", |
155 | req->type); | |
a61f334f | 156 | return -EINVAL; |
d50084a2 JD |
157 | } |
158 | ||
ba180fd4 | 159 | if (n < 0) |
a61f334f JD |
160 | return -errno; |
161 | return 0; | |
75e5584c JD |
162 | } |
163 | ||
9683da91 JD |
164 | /* These are initialized in initcalls and not changed */ |
165 | static int aio_req_fd_r = -1; | |
166 | static int aio_req_fd_w = -1; | |
167 | static int aio_pid = -1; | |
c4399016 | 168 | static unsigned long aio_stack; |
9683da91 | 169 | |
75e5584c JD |
170 | static int not_aio_thread(void *arg) |
171 | { | |
d50084a2 JD |
172 | struct aio_thread_req req; |
173 | struct aio_thread_reply reply; | |
174 | int err; | |
175 | ||
176 | signal(SIGWINCH, SIG_IGN); | |
ba180fd4 | 177 | while (1) { |
a61f334f | 178 | err = read(aio_req_fd_r, &req, sizeof(req)); |
ba180fd4 JD |
179 | if (err != sizeof(req)) { |
180 | if (err < 0) | |
181 | printk(UM_KERN_ERR "not_aio_thread - " | |
182 | "read failed, fd = %d, err = %d\n", | |
183 | aio_req_fd_r, | |
a61f334f | 184 | errno); |
d50084a2 | 185 | else { |
ba180fd4 JD |
186 | printk(UM_KERN_ERR "not_aio_thread - short " |
187 | "read, fd = %d, length = %d\n", | |
188 | aio_req_fd_r, err); | |
d50084a2 JD |
189 | } |
190 | continue; | |
191 | } | |
192 | err = do_not_aio(&req); | |
193 | reply = ((struct aio_thread_reply) { .data = req.aio, | |
ef0470c0 | 194 | .err = err }); |
a61f334f | 195 | err = write(req.aio->reply_fd, &reply, sizeof(reply)); |
ba180fd4 JD |
196 | if (err != sizeof(reply)) |
197 | printk(UM_KERN_ERR "not_aio_thread - write failed, " | |
198 | "fd = %d, err = %d\n", req.aio->reply_fd, errno); | |
d50084a2 | 199 | } |
1b57e9c2 JD |
200 | |
201 | return 0; | |
75e5584c JD |
202 | } |
203 | ||
75e5584c JD |
204 | static int init_aio_24(void) |
205 | { | |
d50084a2 JD |
206 | int fds[2], err; |
207 | ||
208 | err = os_pipe(fds, 1, 1); | |
ba180fd4 | 209 | if (err) |
d50084a2 JD |
210 | goto out; |
211 | ||
212 | aio_req_fd_w = fds[0]; | |
213 | aio_req_fd_r = fds[1]; | |
8603ec81 JD |
214 | |
215 | err = os_set_fd_block(aio_req_fd_w, 0); | |
ba180fd4 | 216 | if (err) |
8603ec81 JD |
217 | goto out_close_pipe; |
218 | ||
d50084a2 | 219 | err = run_helper_thread(not_aio_thread, NULL, |
4dbed85a | 220 | CLONE_FILES | CLONE_VM, &aio_stack); |
ba180fd4 | 221 | if (err < 0) |
d50084a2 JD |
222 | goto out_close_pipe; |
223 | ||
224 | aio_pid = err; | |
225 | goto out; | |
226 | ||
227 | out_close_pipe: | |
512b6fb1 JD |
228 | close(fds[0]); |
229 | close(fds[1]); | |
d50084a2 JD |
230 | aio_req_fd_w = -1; |
231 | aio_req_fd_r = -1; | |
232 | out: | |
75e5584c | 233 | #ifndef HAVE_AIO_ABI |
ba180fd4 JD |
234 | printk(UM_KERN_INFO "/usr/include/linux/aio_abi.h not present during " |
235 | "build\n"); | |
75e5584c | 236 | #endif |
ba180fd4 JD |
237 | printk(UM_KERN_INFO "2.6 host AIO support not used - falling back to " |
238 | "I/O thread\n"); | |
d50084a2 | 239 | return 0; |
75e5584c JD |
240 | } |
241 | ||
242 | #ifdef HAVE_AIO_ABI | |
243 | #define DEFAULT_24_AIO 0 | |
244 | static int init_aio_26(void) | |
245 | { | |
d50084a2 | 246 | int err; |
75e5584c | 247 | |
ba180fd4 | 248 | if (io_setup(256, &ctx)) { |
b4fd310e | 249 | err = -errno; |
ba180fd4 JD |
250 | printk(UM_KERN_ERR "aio_thread failed to initialize context, " |
251 | "err = %d\n", errno); | |
d50084a2 JD |
252 | return err; |
253 | } | |
75e5584c | 254 | |
d50084a2 | 255 | err = run_helper_thread(aio_thread, NULL, |
4dbed85a | 256 | CLONE_FILES | CLONE_VM, &aio_stack); |
ba180fd4 | 257 | if (err < 0) |
d50084a2 | 258 | return err; |
75e5584c | 259 | |
d50084a2 | 260 | aio_pid = err; |
75e5584c | 261 | |
ba180fd4 | 262 | printk(UM_KERN_INFO "Using 2.6 host AIO\n"); |
d50084a2 | 263 | return 0; |
91acb21f JD |
264 | } |
265 | ||
266 | static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len, | |
267 | unsigned long long offset, struct aio_context *aio) | |
268 | { | |
d50084a2 JD |
269 | struct aio_thread_reply reply; |
270 | int err; | |
271 | ||
272 | err = do_aio(ctx, type, io_fd, buf, len, offset, aio); | |
ba180fd4 | 273 | if (err) { |
d50084a2 JD |
274 | reply = ((struct aio_thread_reply) { .data = aio, |
275 | .err = err }); | |
a61f334f | 276 | err = write(aio->reply_fd, &reply, sizeof(reply)); |
ba180fd4 | 277 | if (err != sizeof(reply)) { |
a61f334f | 278 | err = -errno; |
ba180fd4 | 279 | printk(UM_KERN_ERR "submit_aio_26 - write failed, " |
d50084a2 | 280 | "fd = %d, err = %d\n", aio->reply_fd, -err); |
a61f334f | 281 | } |
d50084a2 JD |
282 | else err = 0; |
283 | } | |
284 | ||
285 | return err; | |
75e5584c JD |
286 | } |
287 | ||
288 | #else | |
289 | #define DEFAULT_24_AIO 1 | |
91acb21f | 290 | static int init_aio_26(void) |
75e5584c | 291 | { |
d50084a2 | 292 | return -ENOSYS; |
75e5584c JD |
293 | } |
294 | ||
91acb21f JD |
295 | static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len, |
296 | unsigned long long offset, struct aio_context *aio) | |
75e5584c | 297 | { |
d50084a2 | 298 | return -ENOSYS; |
75e5584c JD |
299 | } |
300 | #endif | |
301 | ||
9683da91 | 302 | /* Initialized in an initcall and unchanged thereafter */ |
75e5584c JD |
303 | static int aio_24 = DEFAULT_24_AIO; |
304 | ||
305 | static int __init set_aio_24(char *name, int *add) | |
306 | { | |
d50084a2 JD |
307 | aio_24 = 1; |
308 | return 0; | |
75e5584c JD |
309 | } |
310 | ||
311 | __uml_setup("aio=2.4", set_aio_24, | |
312 | "aio=2.4\n" | |
313 | " This is used to force UML to use 2.4-style AIO even when 2.6 AIO is\n" | |
314 | " available. 2.4 AIO is a single thread that handles one request at a\n" | |
315 | " time, synchronously. 2.6 AIO is a thread which uses the 2.6 AIO \n" | |
316 | " interface to handle an arbitrary number of pending requests. 2.6 AIO \n" | |
317 | " is not available in tt mode, on 2.4 hosts, or when UML is built with\n" | |
318 | " /usr/include/linux/aio_abi.h not available. Many distributions don't\n" | |
319 | " include aio_abi.h, so you will need to copy it from a kernel tree to\n" | |
320 | " your /usr/include/linux in order to build an AIO-capable UML\n\n" | |
321 | ); | |
322 | ||
323 | static int init_aio(void) | |
324 | { | |
d50084a2 JD |
325 | int err; |
326 | ||
ba180fd4 | 327 | if (!aio_24) { |
d50084a2 | 328 | err = init_aio_26(); |
ba180fd4 JD |
329 | if (err && (errno == ENOSYS)) { |
330 | printk(UM_KERN_INFO "2.6 AIO not supported on the " | |
331 | "host - reverting to 2.4 AIO\n"); | |
d50084a2 JD |
332 | aio_24 = 1; |
333 | } | |
334 | else return err; | |
335 | } | |
336 | ||
ba180fd4 | 337 | if (aio_24) |
d50084a2 JD |
338 | return init_aio_24(); |
339 | ||
340 | return 0; | |
75e5584c JD |
341 | } |
342 | ||
ba180fd4 JD |
343 | /* |
344 | * The reason for the __initcall/__uml_exitcall asymmetry is that init_aio | |
75e5584c JD |
345 | * needs to be called when the kernel is running because it calls run_helper, |
346 | * which needs get_free_page. exit_aio is a __uml_exitcall because the generic | |
347 | * kernel does not run __exitcalls on shutdown, and can't because many of them | |
348 | * break when called outside of module unloading. | |
349 | */ | |
350 | __initcall(init_aio); | |
351 | ||
352 | static void exit_aio(void) | |
353 | { | |
c4399016 | 354 | if (aio_pid != -1) { |
d50084a2 | 355 | os_kill_process(aio_pid, 1); |
c4399016 JD |
356 | free_stack(aio_stack, 0); |
357 | } | |
75e5584c JD |
358 | } |
359 | ||
360 | __uml_exitcall(exit_aio); | |
361 | ||
91acb21f JD |
362 | static int submit_aio_24(enum aio_type type, int io_fd, char *buf, int len, |
363 | unsigned long long offset, struct aio_context *aio) | |
75e5584c | 364 | { |
d50084a2 JD |
365 | struct aio_thread_req req = { .type = type, |
366 | .io_fd = io_fd, | |
367 | .offset = offset, | |
368 | .buf = buf, | |
369 | .len = len, | |
370 | .aio = aio, | |
371 | }; | |
372 | int err; | |
373 | ||
a61f334f | 374 | err = write(aio_req_fd_w, &req, sizeof(req)); |
ba180fd4 | 375 | if (err == sizeof(req)) |
d50084a2 | 376 | err = 0; |
a61f334f | 377 | else err = -errno; |
d50084a2 JD |
378 | |
379 | return err; | |
91acb21f JD |
380 | } |
381 | ||
382 | int submit_aio(enum aio_type type, int io_fd, char *buf, int len, | |
d50084a2 JD |
383 | unsigned long long offset, int reply_fd, |
384 | struct aio_context *aio) | |
91acb21f | 385 | { |
d50084a2 | 386 | aio->reply_fd = reply_fd; |
ba180fd4 | 387 | if (aio_24) |
d50084a2 | 388 | return submit_aio_24(type, io_fd, buf, len, offset, aio); |
ba180fd4 | 389 | else |
d50084a2 | 390 | return submit_aio_26(type, io_fd, buf, len, offset, aio); |
75e5584c | 391 | } |