1/*-
2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Portions of this software were developed under sponsorship from Snow
6 * B.V., the Netherlands.
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#include <sys/cdefs.h>
| 1/*-
2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Portions of this software were developed under sponsorship from Snow
6 * B.V., the Netherlands.
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#include <sys/cdefs.h>
|
32
33#include <sys/param.h>
34#include <sys/kernel.h>
35#include <sys/lock.h>
36#include <sys/queue.h>
37#include <sys/systm.h>
38#include <sys/tty.h>
39#include <sys/uio.h>
40
41#include <vm/uma.h>
42
43/*
44 * TTY output queue buffering.
45 *
46 * The previous design of the TTY layer offered the so-called clists.
47 * These clists were used for both the input queues and the output
48 * queue. We don't use certain features on the output side, like quoting
49 * bits for parity marking and such. This mechanism is similar to the
50 * old clists, but only contains the features we need to buffer the
51 * output.
52 */
53
54struct ttyoutq_block {
55 struct ttyoutq_block *tob_next;
56 char tob_data[TTYOUTQ_DATASIZE];
57};
58
59static uma_zone_t ttyoutq_zone;
60
61#define TTYOUTQ_INSERT_TAIL(to, tob) do { \
62 if (to->to_end == 0) { \
63 tob->tob_next = to->to_firstblock; \
64 to->to_firstblock = tob; \
65 } else { \
66 tob->tob_next = to->to_lastblock->tob_next; \
67 to->to_lastblock->tob_next = tob; \
68 } \
69 to->to_nblocks++; \
70} while (0)
71
72#define TTYOUTQ_REMOVE_HEAD(to) do { \
73 to->to_firstblock = to->to_firstblock->tob_next; \
74 to->to_nblocks--; \
75} while (0)
76
77#define TTYOUTQ_RECYCLE(to, tob) do { \
78 if (to->to_quota <= to->to_nblocks) \
79 uma_zfree(ttyoutq_zone, tob); \
80 else \
81 TTYOUTQ_INSERT_TAIL(to, tob); \
82} while(0)
83
84void
85ttyoutq_flush(struct ttyoutq *to)
86{
87
88 to->to_begin = 0;
89 to->to_end = 0;
90}
91
92void
93ttyoutq_setsize(struct ttyoutq *to, struct tty *tp, size_t size)
94{
95 struct ttyoutq_block *tob;
96
97 to->to_quota = howmany(size, TTYOUTQ_DATASIZE);
98
99 while (to->to_quota > to->to_nblocks) {
100 /*
101 * List is getting bigger.
102 * Add new blocks to the tail of the list.
103 *
104 * We must unlock the TTY temporarily, because we need
105 * to allocate memory. This won't be a problem, because
106 * in the worst case, another thread ends up here, which
107 * may cause us to allocate too many blocks, but this
108 * will be caught by the loop below.
109 */
110 tty_unlock(tp);
111 tob = uma_zalloc(ttyoutq_zone, M_WAITOK);
112 tty_lock(tp);
113
114 TTYOUTQ_INSERT_TAIL(to, tob);
115 }
116}
117
118void
119ttyoutq_free(struct ttyoutq *to)
120{
121 struct ttyoutq_block *tob;
| 32
33#include <sys/param.h>
34#include <sys/kernel.h>
35#include <sys/lock.h>
36#include <sys/queue.h>
37#include <sys/systm.h>
38#include <sys/tty.h>
39#include <sys/uio.h>
40
41#include <vm/uma.h>
42
43/*
44 * TTY output queue buffering.
45 *
46 * The previous design of the TTY layer offered the so-called clists.
47 * These clists were used for both the input queues and the output
48 * queue. We don't use certain features on the output side, like quoting
49 * bits for parity marking and such. This mechanism is similar to the
50 * old clists, but only contains the features we need to buffer the
51 * output.
52 */
53
54struct ttyoutq_block {
55 struct ttyoutq_block *tob_next;
56 char tob_data[TTYOUTQ_DATASIZE];
57};
58
59static uma_zone_t ttyoutq_zone;
60
61#define TTYOUTQ_INSERT_TAIL(to, tob) do { \
62 if (to->to_end == 0) { \
63 tob->tob_next = to->to_firstblock; \
64 to->to_firstblock = tob; \
65 } else { \
66 tob->tob_next = to->to_lastblock->tob_next; \
67 to->to_lastblock->tob_next = tob; \
68 } \
69 to->to_nblocks++; \
70} while (0)
71
72#define TTYOUTQ_REMOVE_HEAD(to) do { \
73 to->to_firstblock = to->to_firstblock->tob_next; \
74 to->to_nblocks--; \
75} while (0)
76
77#define TTYOUTQ_RECYCLE(to, tob) do { \
78 if (to->to_quota <= to->to_nblocks) \
79 uma_zfree(ttyoutq_zone, tob); \
80 else \
81 TTYOUTQ_INSERT_TAIL(to, tob); \
82} while(0)
83
84void
85ttyoutq_flush(struct ttyoutq *to)
86{
87
88 to->to_begin = 0;
89 to->to_end = 0;
90}
91
92void
93ttyoutq_setsize(struct ttyoutq *to, struct tty *tp, size_t size)
94{
95 struct ttyoutq_block *tob;
96
97 to->to_quota = howmany(size, TTYOUTQ_DATASIZE);
98
99 while (to->to_quota > to->to_nblocks) {
100 /*
101 * List is getting bigger.
102 * Add new blocks to the tail of the list.
103 *
104 * We must unlock the TTY temporarily, because we need
105 * to allocate memory. This won't be a problem, because
106 * in the worst case, another thread ends up here, which
107 * may cause us to allocate too many blocks, but this
108 * will be caught by the loop below.
109 */
110 tty_unlock(tp);
111 tob = uma_zalloc(ttyoutq_zone, M_WAITOK);
112 tty_lock(tp);
113
114 TTYOUTQ_INSERT_TAIL(to, tob);
115 }
116}
117
118void
119ttyoutq_free(struct ttyoutq *to)
120{
121 struct ttyoutq_block *tob;
|
123 ttyoutq_flush(to);
124 to->to_quota = 0;
125
126 while ((tob = to->to_firstblock) != NULL) {
127 TTYOUTQ_REMOVE_HEAD(to);
128 uma_zfree(ttyoutq_zone, tob);
129 }
130
131 MPASS(to->to_nblocks == 0);
132}
133
134size_t
135ttyoutq_read(struct ttyoutq *to, void *buf, size_t len)
136{
137 char *cbuf = buf;
138
139 while (len > 0) {
140 struct ttyoutq_block *tob;
141 size_t cbegin, cend, clen;
142
143 /* See if there still is data. */
144 if (to->to_begin == to->to_end)
145 break;
146 tob = to->to_firstblock;
147 if (tob == NULL)
148 break;
149
150 /*
151 * The end address should be the lowest of these three:
152 * - The write pointer
153 * - The blocksize - we can't read beyond the block
154 * - The end address if we could perform the full read
155 */
156 cbegin = to->to_begin;
157 cend = MIN(MIN(to->to_end, to->to_begin + len),
158 TTYOUTQ_DATASIZE);
159 clen = cend - cbegin;
160
161 /* Copy the data out of the buffers. */
162 memcpy(cbuf, tob->tob_data + cbegin, clen);
163 cbuf += clen;
164 len -= clen;
165
166 if (cend == to->to_end) {
167 /* Read the complete queue. */
168 to->to_begin = 0;
169 to->to_end = 0;
170 } else if (cend == TTYOUTQ_DATASIZE) {
171 /* Read the block until the end. */
172 TTYOUTQ_REMOVE_HEAD(to);
173 to->to_begin = 0;
174 to->to_end -= TTYOUTQ_DATASIZE;
175 TTYOUTQ_RECYCLE(to, tob);
176 } else {
177 /* Read the block partially. */
178 to->to_begin += clen;
179 }
180 }
181
182 return (cbuf - (char *)buf);
183}
184
185/*
186 * An optimized version of ttyoutq_read() which can be used in pseudo
187 * TTY drivers to directly copy data from the outq to userspace, instead
188 * of buffering it.
189 *
190 * We can only copy data directly if we need to read the entire block
191 * back to the user, because we temporarily remove the block from the
192 * queue. Otherwise we need to copy it to a temporary buffer first, to
193 * make sure data remains in the correct order.
194 */
195int
196ttyoutq_read_uio(struct ttyoutq *to, struct tty *tp, struct uio *uio)
197{
198
199 while (uio->uio_resid > 0) {
200 int error;
201 struct ttyoutq_block *tob;
202 size_t cbegin, cend, clen;
203
204 /* See if there still is data. */
205 if (to->to_begin == to->to_end)
206 return (0);
207 tob = to->to_firstblock;
208 if (tob == NULL)
209 return (0);
210
211 /*
212 * The end address should be the lowest of these three:
213 * - The write pointer
214 * - The blocksize - we can't read beyond the block
215 * - The end address if we could perform the full read
216 */
217 cbegin = to->to_begin;
218 cend = MIN(MIN(to->to_end, to->to_begin + uio->uio_resid),
219 TTYOUTQ_DATASIZE);
220 clen = cend - cbegin;
221
222 /*
223 * We can prevent buffering in some cases:
224 * - We need to read the block until the end.
225 * - We don't need to read the block until the end, but
226 * there is no data beyond it, which allows us to move
227 * the write pointer to a new block.
228 */
229 if (cend == TTYOUTQ_DATASIZE || cend == to->to_end) {
230 /*
231 * Fast path: zero copy. Remove the first block,
232 * so we can unlock the TTY temporarily.
233 */
234 TTYOUTQ_REMOVE_HEAD(to);
235 to->to_begin = 0;
236 if (to->to_end <= TTYOUTQ_DATASIZE)
237 to->to_end = 0;
238 else
239 to->to_end -= TTYOUTQ_DATASIZE;
240
241 /* Temporary unlock and copy the data to userspace. */
242 tty_unlock(tp);
243 error = uiomove(tob->tob_data + cbegin, clen, uio);
244 tty_lock(tp);
245
246 /* Block can now be readded to the list. */
247 TTYOUTQ_RECYCLE(to, tob);
248 } else {
249 char ob[TTYOUTQ_DATASIZE - 1];
250
251 /*
252 * Slow path: store data in a temporary buffer.
253 */
254 memcpy(ob, tob->tob_data + cbegin, clen);
255 to->to_begin += clen;
256 MPASS(to->to_begin < TTYOUTQ_DATASIZE);
257
258 /* Temporary unlock and copy the data to userspace. */
259 tty_unlock(tp);
260 error = uiomove(ob, clen, uio);
261 tty_lock(tp);
262 }
263
264 if (error != 0)
265 return (error);
266 }
267
268 return (0);
269}
270
271size_t
272ttyoutq_write(struct ttyoutq *to, const void *buf, size_t nbytes)
273{
274 const char *cbuf = buf;
275 struct ttyoutq_block *tob;
276 unsigned int boff;
277 size_t l;
278
279 while (nbytes > 0) {
280 boff = to->to_end % TTYOUTQ_DATASIZE;
281
282 if (to->to_end == 0) {
283 /* First time we're being used or drained. */
284 MPASS(to->to_begin == 0);
285 tob = to->to_firstblock;
286 if (tob == NULL) {
287 /* Queue has no blocks. */
288 break;
289 }
290 to->to_lastblock = tob;
291 } else if (boff == 0) {
292 /* We reached the end of this block on last write. */
293 tob = to->to_lastblock->tob_next;
294 if (tob == NULL) {
295 /* We've reached the watermark. */
296 break;
297 }
298 to->to_lastblock = tob;
299 } else {
300 tob = to->to_lastblock;
301 }
302
303 /* Don't copy more than was requested. */
304 l = MIN(nbytes, TTYOUTQ_DATASIZE - boff);
305 MPASS(l > 0);
306 memcpy(tob->tob_data + boff, cbuf, l);
307
308 cbuf += l;
309 nbytes -= l;
310 to->to_end += l;
311 }
312
313 return (cbuf - (const char *)buf);
314}
315
316int
317ttyoutq_write_nofrag(struct ttyoutq *to, const void *buf, size_t nbytes)
318{
319 size_t ret;
320
321 if (ttyoutq_bytesleft(to) < nbytes)
322 return (-1);
323
324 /* We should always be able to write it back. */
325 ret = ttyoutq_write(to, buf, nbytes);
326 MPASS(ret == nbytes);
327
328 return (0);
329}
330
331static void
332ttyoutq_startup(void *dummy)
333{
334
335 ttyoutq_zone = uma_zcreate("ttyoutq", sizeof(struct ttyoutq_block),
336 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
337}
338
339SYSINIT(ttyoutq, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyoutq_startup, NULL);
| 123 ttyoutq_flush(to);
124 to->to_quota = 0;
125
126 while ((tob = to->to_firstblock) != NULL) {
127 TTYOUTQ_REMOVE_HEAD(to);
128 uma_zfree(ttyoutq_zone, tob);
129 }
130
131 MPASS(to->to_nblocks == 0);
132}
133
134size_t
135ttyoutq_read(struct ttyoutq *to, void *buf, size_t len)
136{
137 char *cbuf = buf;
138
139 while (len > 0) {
140 struct ttyoutq_block *tob;
141 size_t cbegin, cend, clen;
142
143 /* See if there still is data. */
144 if (to->to_begin == to->to_end)
145 break;
146 tob = to->to_firstblock;
147 if (tob == NULL)
148 break;
149
150 /*
151 * The end address should be the lowest of these three:
152 * - The write pointer
153 * - The blocksize - we can't read beyond the block
154 * - The end address if we could perform the full read
155 */
156 cbegin = to->to_begin;
157 cend = MIN(MIN(to->to_end, to->to_begin + len),
158 TTYOUTQ_DATASIZE);
159 clen = cend - cbegin;
160
161 /* Copy the data out of the buffers. */
162 memcpy(cbuf, tob->tob_data + cbegin, clen);
163 cbuf += clen;
164 len -= clen;
165
166 if (cend == to->to_end) {
167 /* Read the complete queue. */
168 to->to_begin = 0;
169 to->to_end = 0;
170 } else if (cend == TTYOUTQ_DATASIZE) {
171 /* Read the block until the end. */
172 TTYOUTQ_REMOVE_HEAD(to);
173 to->to_begin = 0;
174 to->to_end -= TTYOUTQ_DATASIZE;
175 TTYOUTQ_RECYCLE(to, tob);
176 } else {
177 /* Read the block partially. */
178 to->to_begin += clen;
179 }
180 }
181
182 return (cbuf - (char *)buf);
183}
184
185/*
186 * An optimized version of ttyoutq_read() which can be used in pseudo
187 * TTY drivers to directly copy data from the outq to userspace, instead
188 * of buffering it.
189 *
190 * We can only copy data directly if we need to read the entire block
191 * back to the user, because we temporarily remove the block from the
192 * queue. Otherwise we need to copy it to a temporary buffer first, to
193 * make sure data remains in the correct order.
194 */
195int
196ttyoutq_read_uio(struct ttyoutq *to, struct tty *tp, struct uio *uio)
197{
198
199 while (uio->uio_resid > 0) {
200 int error;
201 struct ttyoutq_block *tob;
202 size_t cbegin, cend, clen;
203
204 /* See if there still is data. */
205 if (to->to_begin == to->to_end)
206 return (0);
207 tob = to->to_firstblock;
208 if (tob == NULL)
209 return (0);
210
211 /*
212 * The end address should be the lowest of these three:
213 * - The write pointer
214 * - The blocksize - we can't read beyond the block
215 * - The end address if we could perform the full read
216 */
217 cbegin = to->to_begin;
218 cend = MIN(MIN(to->to_end, to->to_begin + uio->uio_resid),
219 TTYOUTQ_DATASIZE);
220 clen = cend - cbegin;
221
222 /*
223 * We can prevent buffering in some cases:
224 * - We need to read the block until the end.
225 * - We don't need to read the block until the end, but
226 * there is no data beyond it, which allows us to move
227 * the write pointer to a new block.
228 */
229 if (cend == TTYOUTQ_DATASIZE || cend == to->to_end) {
230 /*
231 * Fast path: zero copy. Remove the first block,
232 * so we can unlock the TTY temporarily.
233 */
234 TTYOUTQ_REMOVE_HEAD(to);
235 to->to_begin = 0;
236 if (to->to_end <= TTYOUTQ_DATASIZE)
237 to->to_end = 0;
238 else
239 to->to_end -= TTYOUTQ_DATASIZE;
240
241 /* Temporary unlock and copy the data to userspace. */
242 tty_unlock(tp);
243 error = uiomove(tob->tob_data + cbegin, clen, uio);
244 tty_lock(tp);
245
246 /* Block can now be readded to the list. */
247 TTYOUTQ_RECYCLE(to, tob);
248 } else {
249 char ob[TTYOUTQ_DATASIZE - 1];
250
251 /*
252 * Slow path: store data in a temporary buffer.
253 */
254 memcpy(ob, tob->tob_data + cbegin, clen);
255 to->to_begin += clen;
256 MPASS(to->to_begin < TTYOUTQ_DATASIZE);
257
258 /* Temporary unlock and copy the data to userspace. */
259 tty_unlock(tp);
260 error = uiomove(ob, clen, uio);
261 tty_lock(tp);
262 }
263
264 if (error != 0)
265 return (error);
266 }
267
268 return (0);
269}
270
271size_t
272ttyoutq_write(struct ttyoutq *to, const void *buf, size_t nbytes)
273{
274 const char *cbuf = buf;
275 struct ttyoutq_block *tob;
276 unsigned int boff;
277 size_t l;
278
279 while (nbytes > 0) {
280 boff = to->to_end % TTYOUTQ_DATASIZE;
281
282 if (to->to_end == 0) {
283 /* First time we're being used or drained. */
284 MPASS(to->to_begin == 0);
285 tob = to->to_firstblock;
286 if (tob == NULL) {
287 /* Queue has no blocks. */
288 break;
289 }
290 to->to_lastblock = tob;
291 } else if (boff == 0) {
292 /* We reached the end of this block on last write. */
293 tob = to->to_lastblock->tob_next;
294 if (tob == NULL) {
295 /* We've reached the watermark. */
296 break;
297 }
298 to->to_lastblock = tob;
299 } else {
300 tob = to->to_lastblock;
301 }
302
303 /* Don't copy more than was requested. */
304 l = MIN(nbytes, TTYOUTQ_DATASIZE - boff);
305 MPASS(l > 0);
306 memcpy(tob->tob_data + boff, cbuf, l);
307
308 cbuf += l;
309 nbytes -= l;
310 to->to_end += l;
311 }
312
313 return (cbuf - (const char *)buf);
314}
315
316int
317ttyoutq_write_nofrag(struct ttyoutq *to, const void *buf, size_t nbytes)
318{
319 size_t ret;
320
321 if (ttyoutq_bytesleft(to) < nbytes)
322 return (-1);
323
324 /* We should always be able to write it back. */
325 ret = ttyoutq_write(to, buf, nbytes);
326 MPASS(ret == nbytes);
327
328 return (0);
329}
330
331static void
332ttyoutq_startup(void *dummy)
333{
334
335 ttyoutq_zone = uma_zcreate("ttyoutq", sizeof(struct ttyoutq_block),
336 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
337}
338
339SYSINIT(ttyoutq, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyoutq_startup, NULL);
|