]>
Commit | Line | Data |
---|---|---|
d021c344 AK |
1 | /* |
2 | * VMware vSockets Driver | |
3 | * | |
4 | * Copyright (C) 2009-2013 VMware, Inc. All rights reserved. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License as published by the Free | |
8 | * Software Foundation version 2 and no later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | */ | |
15 | ||
16 | #include <linux/types.h> | |
17 | #include <linux/socket.h> | |
18 | #include <linux/stddef.h> | |
19 | #include <net/sock.h> | |
20 | ||
21 | #include "vmci_transport_notify.h" | |
22 | ||
23 | #define PKT_FIELD(vsk, field_name) \ | |
24 | (vmci_trans(vsk)->notify.pkt_q_state.field_name) | |
25 | ||
26 | static bool vmci_transport_notify_waiting_write(struct vsock_sock *vsk) | |
27 | { | |
28 | bool retval; | |
29 | u64 notify_limit; | |
30 | ||
31 | if (!PKT_FIELD(vsk, peer_waiting_write)) | |
32 | return false; | |
33 | ||
34 | /* When the sender blocks, we take that as a sign that the sender is | |
35 | * faster than the receiver. To reduce the transmit rate of the sender, | |
36 | * we delay the sending of the read notification by decreasing the | |
37 | * write_notify_window. The notification is delayed until the number of | |
38 | * bytes used in the queue drops below the write_notify_window. | |
39 | */ | |
40 | ||
41 | if (!PKT_FIELD(vsk, peer_waiting_write_detected)) { | |
42 | PKT_FIELD(vsk, peer_waiting_write_detected) = true; | |
43 | if (PKT_FIELD(vsk, write_notify_window) < PAGE_SIZE) { | |
44 | PKT_FIELD(vsk, write_notify_window) = | |
45 | PKT_FIELD(vsk, write_notify_min_window); | |
46 | } else { | |
47 | PKT_FIELD(vsk, write_notify_window) -= PAGE_SIZE; | |
48 | if (PKT_FIELD(vsk, write_notify_window) < | |
49 | PKT_FIELD(vsk, write_notify_min_window)) | |
50 | PKT_FIELD(vsk, write_notify_window) = | |
51 | PKT_FIELD(vsk, write_notify_min_window); | |
52 | ||
53 | } | |
54 | } | |
55 | notify_limit = vmci_trans(vsk)->consume_size - | |
56 | PKT_FIELD(vsk, write_notify_window); | |
57 | ||
58 | /* The notify_limit is used to delay notifications in the case where | |
59 | * flow control is enabled. Below the test is expressed in terms of | |
60 | * free space in the queue: if free_space > ConsumeSize - | |
61 | * write_notify_window then notify An alternate way of expressing this | |
62 | * is to rewrite the expression to use the data ready in the receive | |
63 | * queue: if write_notify_window > bufferReady then notify as | |
64 | * free_space == ConsumeSize - bufferReady. | |
65 | */ | |
66 | ||
67 | retval = vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair) > | |
68 | notify_limit; | |
69 | ||
70 | if (retval) { | |
71 | /* Once we notify the peer, we reset the detected flag so the | |
72 | * next wait will again cause a decrease in the window size. | |
73 | */ | |
74 | ||
75 | PKT_FIELD(vsk, peer_waiting_write_detected) = false; | |
76 | } | |
77 | return retval; | |
78 | } | |
79 | ||
80 | static void | |
81 | vmci_transport_handle_read(struct sock *sk, | |
82 | struct vmci_transport_packet *pkt, | |
83 | bool bottom_half, | |
84 | struct sockaddr_vm *dst, struct sockaddr_vm *src) | |
85 | { | |
86 | sk->sk_write_space(sk); | |
87 | } | |
88 | ||
89 | static void | |
90 | vmci_transport_handle_wrote(struct sock *sk, | |
91 | struct vmci_transport_packet *pkt, | |
92 | bool bottom_half, | |
93 | struct sockaddr_vm *dst, struct sockaddr_vm *src) | |
94 | { | |
676d2369 | 95 | sk->sk_data_ready(sk); |
d021c344 AK |
96 | } |
97 | ||
98 | static void vsock_block_update_write_window(struct sock *sk) | |
99 | { | |
100 | struct vsock_sock *vsk = vsock_sk(sk); | |
101 | ||
102 | if (PKT_FIELD(vsk, write_notify_window) < vmci_trans(vsk)->consume_size) | |
103 | PKT_FIELD(vsk, write_notify_window) = | |
104 | min(PKT_FIELD(vsk, write_notify_window) + PAGE_SIZE, | |
105 | vmci_trans(vsk)->consume_size); | |
106 | } | |
107 | ||
108 | static int vmci_transport_send_read_notification(struct sock *sk) | |
109 | { | |
110 | struct vsock_sock *vsk; | |
111 | bool sent_read; | |
112 | unsigned int retries; | |
113 | int err; | |
114 | ||
115 | vsk = vsock_sk(sk); | |
116 | sent_read = false; | |
117 | retries = 0; | |
118 | err = 0; | |
119 | ||
120 | if (vmci_transport_notify_waiting_write(vsk)) { | |
121 | /* Notify the peer that we have read, retrying the send on | |
122 | * failure up to our maximum value. XXX For now we just log | |
123 | * the failure, but later we should schedule a work item to | |
124 | * handle the resend until it succeeds. That would require | |
125 | * keeping track of work items in the vsk and cleaning them up | |
126 | * upon socket close. | |
127 | */ | |
128 | while (!(vsk->peer_shutdown & RCV_SHUTDOWN) && | |
129 | !sent_read && | |
130 | retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) { | |
131 | err = vmci_transport_send_read(sk); | |
132 | if (err >= 0) | |
133 | sent_read = true; | |
134 | ||
135 | retries++; | |
136 | } | |
137 | ||
138 | if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_read) | |
139 | pr_err("%p unable to send read notification to peer\n", | |
140 | sk); | |
141 | else | |
142 | PKT_FIELD(vsk, peer_waiting_write) = false; | |
143 | ||
144 | } | |
145 | return err; | |
146 | } | |
147 | ||
148 | static void vmci_transport_notify_pkt_socket_init(struct sock *sk) | |
149 | { | |
150 | struct vsock_sock *vsk = vsock_sk(sk); | |
151 | ||
152 | PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE; | |
153 | PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE; | |
154 | PKT_FIELD(vsk, peer_waiting_write) = false; | |
155 | PKT_FIELD(vsk, peer_waiting_write_detected) = false; | |
156 | } | |
157 | ||
158 | static void vmci_transport_notify_pkt_socket_destruct(struct vsock_sock *vsk) | |
159 | { | |
160 | PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE; | |
161 | PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE; | |
162 | PKT_FIELD(vsk, peer_waiting_write) = false; | |
163 | PKT_FIELD(vsk, peer_waiting_write_detected) = false; | |
164 | } | |
165 | ||
166 | static int | |
167 | vmci_transport_notify_pkt_poll_in(struct sock *sk, | |
168 | size_t target, bool *data_ready_now) | |
169 | { | |
170 | struct vsock_sock *vsk = vsock_sk(sk); | |
171 | ||
172 | if (vsock_stream_has_data(vsk)) { | |
173 | *data_ready_now = true; | |
174 | } else { | |
175 | /* We can't read right now because there is nothing in the | |
176 | * queue. Ask for notifications when there is something to | |
177 | * read. | |
178 | */ | |
179 | if (sk->sk_state == SS_CONNECTED) | |
180 | vsock_block_update_write_window(sk); | |
181 | *data_ready_now = false; | |
182 | } | |
183 | ||
184 | return 0; | |
185 | } | |
186 | ||
187 | static int | |
188 | vmci_transport_notify_pkt_poll_out(struct sock *sk, | |
189 | size_t target, bool *space_avail_now) | |
190 | { | |
191 | s64 produce_q_free_space; | |
192 | struct vsock_sock *vsk = vsock_sk(sk); | |
193 | ||
194 | produce_q_free_space = vsock_stream_has_space(vsk); | |
195 | if (produce_q_free_space > 0) { | |
196 | *space_avail_now = true; | |
197 | return 0; | |
198 | } else if (produce_q_free_space == 0) { | |
199 | /* This is a connected socket but we can't currently send data. | |
200 | * Nothing else to do. | |
201 | */ | |
202 | *space_avail_now = false; | |
203 | } | |
204 | ||
205 | return 0; | |
206 | } | |
207 | ||
208 | static int | |
209 | vmci_transport_notify_pkt_recv_init( | |
210 | struct sock *sk, | |
211 | size_t target, | |
212 | struct vmci_transport_recv_notify_data *data) | |
213 | { | |
214 | struct vsock_sock *vsk = vsock_sk(sk); | |
215 | ||
216 | data->consume_head = 0; | |
217 | data->produce_tail = 0; | |
218 | data->notify_on_block = false; | |
219 | ||
220 | if (PKT_FIELD(vsk, write_notify_min_window) < target + 1) { | |
221 | PKT_FIELD(vsk, write_notify_min_window) = target + 1; | |
222 | if (PKT_FIELD(vsk, write_notify_window) < | |
223 | PKT_FIELD(vsk, write_notify_min_window)) { | |
224 | /* If the current window is smaller than the new | |
225 | * minimal window size, we need to reevaluate whether | |
226 | * we need to notify the sender. If the number of ready | |
227 | * bytes are smaller than the new window, we need to | |
228 | * send a notification to the sender before we block. | |
229 | */ | |
230 | ||
231 | PKT_FIELD(vsk, write_notify_window) = | |
232 | PKT_FIELD(vsk, write_notify_min_window); | |
233 | data->notify_on_block = true; | |
234 | } | |
235 | } | |
236 | ||
237 | return 0; | |
238 | } | |
239 | ||
240 | static int | |
241 | vmci_transport_notify_pkt_recv_pre_block( | |
242 | struct sock *sk, | |
243 | size_t target, | |
244 | struct vmci_transport_recv_notify_data *data) | |
245 | { | |
246 | int err = 0; | |
247 | ||
248 | vsock_block_update_write_window(sk); | |
249 | ||
250 | if (data->notify_on_block) { | |
251 | err = vmci_transport_send_read_notification(sk); | |
252 | if (err < 0) | |
253 | return err; | |
254 | data->notify_on_block = false; | |
255 | } | |
256 | ||
257 | return err; | |
258 | } | |
259 | ||
260 | static int | |
261 | vmci_transport_notify_pkt_recv_post_dequeue( | |
262 | struct sock *sk, | |
263 | size_t target, | |
264 | ssize_t copied, | |
265 | bool data_read, | |
266 | struct vmci_transport_recv_notify_data *data) | |
267 | { | |
268 | struct vsock_sock *vsk; | |
269 | int err; | |
270 | bool was_full = false; | |
271 | u64 free_space; | |
272 | ||
273 | vsk = vsock_sk(sk); | |
274 | err = 0; | |
275 | ||
276 | if (data_read) { | |
277 | smp_mb(); | |
278 | ||
279 | free_space = | |
280 | vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair); | |
281 | was_full = free_space == copied; | |
282 | ||
283 | if (was_full) | |
284 | PKT_FIELD(vsk, peer_waiting_write) = true; | |
285 | ||
286 | err = vmci_transport_send_read_notification(sk); | |
287 | if (err < 0) | |
288 | return err; | |
289 | ||
290 | /* See the comment in | |
291 | * vmci_transport_notify_pkt_send_post_enqueue(). | |
292 | */ | |
676d2369 | 293 | sk->sk_data_ready(sk); |
d021c344 AK |
294 | } |
295 | ||
296 | return err; | |
297 | } | |
298 | ||
299 | static int | |
300 | vmci_transport_notify_pkt_send_init( | |
301 | struct sock *sk, | |
302 | struct vmci_transport_send_notify_data *data) | |
303 | { | |
304 | data->consume_head = 0; | |
305 | data->produce_tail = 0; | |
306 | ||
307 | return 0; | |
308 | } | |
309 | ||
310 | static int | |
311 | vmci_transport_notify_pkt_send_post_enqueue( | |
312 | struct sock *sk, | |
313 | ssize_t written, | |
314 | struct vmci_transport_send_notify_data *data) | |
315 | { | |
316 | int err = 0; | |
317 | struct vsock_sock *vsk; | |
318 | bool sent_wrote = false; | |
319 | bool was_empty; | |
320 | int retries = 0; | |
321 | ||
322 | vsk = vsock_sk(sk); | |
323 | ||
324 | smp_mb(); | |
325 | ||
326 | was_empty = | |
327 | vmci_qpair_produce_buf_ready(vmci_trans(vsk)->qpair) == written; | |
328 | if (was_empty) { | |
329 | while (!(vsk->peer_shutdown & RCV_SHUTDOWN) && | |
330 | !sent_wrote && | |
331 | retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) { | |
332 | err = vmci_transport_send_wrote(sk); | |
333 | if (err >= 0) | |
334 | sent_wrote = true; | |
335 | ||
336 | retries++; | |
337 | } | |
338 | } | |
339 | ||
340 | if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_wrote) { | |
341 | pr_err("%p unable to send wrote notification to peer\n", | |
342 | sk); | |
343 | return err; | |
344 | } | |
345 | ||
346 | return err; | |
347 | } | |
348 | ||
349 | static void | |
350 | vmci_transport_notify_pkt_handle_pkt( | |
351 | struct sock *sk, | |
352 | struct vmci_transport_packet *pkt, | |
353 | bool bottom_half, | |
354 | struct sockaddr_vm *dst, | |
355 | struct sockaddr_vm *src, bool *pkt_processed) | |
356 | { | |
357 | bool processed = false; | |
358 | ||
359 | switch (pkt->type) { | |
360 | case VMCI_TRANSPORT_PACKET_TYPE_WROTE: | |
361 | vmci_transport_handle_wrote(sk, pkt, bottom_half, dst, src); | |
362 | processed = true; | |
363 | break; | |
364 | case VMCI_TRANSPORT_PACKET_TYPE_READ: | |
365 | vmci_transport_handle_read(sk, pkt, bottom_half, dst, src); | |
366 | processed = true; | |
367 | break; | |
368 | } | |
369 | ||
370 | if (pkt_processed) | |
371 | *pkt_processed = processed; | |
372 | } | |
373 | ||
374 | static void vmci_transport_notify_pkt_process_request(struct sock *sk) | |
375 | { | |
376 | struct vsock_sock *vsk = vsock_sk(sk); | |
377 | ||
378 | PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size; | |
379 | if (vmci_trans(vsk)->consume_size < | |
380 | PKT_FIELD(vsk, write_notify_min_window)) | |
381 | PKT_FIELD(vsk, write_notify_min_window) = | |
382 | vmci_trans(vsk)->consume_size; | |
383 | } | |
384 | ||
385 | static void vmci_transport_notify_pkt_process_negotiate(struct sock *sk) | |
386 | { | |
387 | struct vsock_sock *vsk = vsock_sk(sk); | |
388 | ||
389 | PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size; | |
390 | if (vmci_trans(vsk)->consume_size < | |
391 | PKT_FIELD(vsk, write_notify_min_window)) | |
392 | PKT_FIELD(vsk, write_notify_min_window) = | |
393 | vmci_trans(vsk)->consume_size; | |
394 | } | |
395 | ||
396 | static int | |
397 | vmci_transport_notify_pkt_recv_pre_dequeue( | |
398 | struct sock *sk, | |
399 | size_t target, | |
400 | struct vmci_transport_recv_notify_data *data) | |
401 | { | |
402 | return 0; /* NOP for QState. */ | |
403 | } | |
404 | ||
405 | static int | |
406 | vmci_transport_notify_pkt_send_pre_block( | |
407 | struct sock *sk, | |
408 | struct vmci_transport_send_notify_data *data) | |
409 | { | |
410 | return 0; /* NOP for QState. */ | |
411 | } | |
412 | ||
413 | static int | |
414 | vmci_transport_notify_pkt_send_pre_enqueue( | |
415 | struct sock *sk, | |
416 | struct vmci_transport_send_notify_data *data) | |
417 | { | |
418 | return 0; /* NOP for QState. */ | |
419 | } | |
420 | ||
421 | /* Socket always on control packet based operations. */ | |
3b22dae3 | 422 | const struct vmci_transport_notify_ops vmci_transport_notify_pkt_q_state_ops = { |
99a5e178 KC |
423 | .socket_init = vmci_transport_notify_pkt_socket_init, |
424 | .socket_destruct = vmci_transport_notify_pkt_socket_destruct, | |
425 | .poll_in = vmci_transport_notify_pkt_poll_in, | |
426 | .poll_out = vmci_transport_notify_pkt_poll_out, | |
427 | .handle_notify_pkt = vmci_transport_notify_pkt_handle_pkt, | |
428 | .recv_init = vmci_transport_notify_pkt_recv_init, | |
429 | .recv_pre_block = vmci_transport_notify_pkt_recv_pre_block, | |
430 | .recv_pre_dequeue = vmci_transport_notify_pkt_recv_pre_dequeue, | |
431 | .recv_post_dequeue = vmci_transport_notify_pkt_recv_post_dequeue, | |
432 | .send_init = vmci_transport_notify_pkt_send_init, | |
433 | .send_pre_block = vmci_transport_notify_pkt_send_pre_block, | |
434 | .send_pre_enqueue = vmci_transport_notify_pkt_send_pre_enqueue, | |
435 | .send_post_enqueue = vmci_transport_notify_pkt_send_post_enqueue, | |
436 | .process_request = vmci_transport_notify_pkt_process_request, | |
437 | .process_negotiate = vmci_transport_notify_pkt_process_negotiate, | |
d021c344 | 438 | }; |