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685a6bf8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d021c344 AK |
2 | /* |
3 | * VMware vSockets Driver | |
4 | * | |
5 | * Copyright (C) 2009-2013 VMware, Inc. All rights reserved. | |
d021c344 AK |
6 | */ |
7 | ||
8 | #include <linux/types.h> | |
9 | #include <linux/socket.h> | |
10 | #include <linux/stddef.h> | |
11 | #include <net/sock.h> | |
12 | ||
13 | #include "vmci_transport_notify.h" | |
14 | ||
15 | #define PKT_FIELD(vsk, field_name) \ | |
16 | (vmci_trans(vsk)->notify.pkt_q_state.field_name) | |
17 | ||
18 | static bool vmci_transport_notify_waiting_write(struct vsock_sock *vsk) | |
19 | { | |
20 | bool retval; | |
21 | u64 notify_limit; | |
22 | ||
23 | if (!PKT_FIELD(vsk, peer_waiting_write)) | |
24 | return false; | |
25 | ||
26 | /* When the sender blocks, we take that as a sign that the sender is | |
27 | * faster than the receiver. To reduce the transmit rate of the sender, | |
28 | * we delay the sending of the read notification by decreasing the | |
29 | * write_notify_window. The notification is delayed until the number of | |
30 | * bytes used in the queue drops below the write_notify_window. | |
31 | */ | |
32 | ||
33 | if (!PKT_FIELD(vsk, peer_waiting_write_detected)) { | |
34 | PKT_FIELD(vsk, peer_waiting_write_detected) = true; | |
35 | if (PKT_FIELD(vsk, write_notify_window) < PAGE_SIZE) { | |
36 | PKT_FIELD(vsk, write_notify_window) = | |
37 | PKT_FIELD(vsk, write_notify_min_window); | |
38 | } else { | |
39 | PKT_FIELD(vsk, write_notify_window) -= PAGE_SIZE; | |
40 | if (PKT_FIELD(vsk, write_notify_window) < | |
41 | PKT_FIELD(vsk, write_notify_min_window)) | |
42 | PKT_FIELD(vsk, write_notify_window) = | |
43 | PKT_FIELD(vsk, write_notify_min_window); | |
44 | ||
45 | } | |
46 | } | |
47 | notify_limit = vmci_trans(vsk)->consume_size - | |
48 | PKT_FIELD(vsk, write_notify_window); | |
49 | ||
50 | /* The notify_limit is used to delay notifications in the case where | |
51 | * flow control is enabled. Below the test is expressed in terms of | |
52 | * free space in the queue: if free_space > ConsumeSize - | |
53 | * write_notify_window then notify An alternate way of expressing this | |
54 | * is to rewrite the expression to use the data ready in the receive | |
55 | * queue: if write_notify_window > bufferReady then notify as | |
56 | * free_space == ConsumeSize - bufferReady. | |
57 | */ | |
58 | ||
59 | retval = vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair) > | |
60 | notify_limit; | |
61 | ||
62 | if (retval) { | |
63 | /* Once we notify the peer, we reset the detected flag so the | |
64 | * next wait will again cause a decrease in the window size. | |
65 | */ | |
66 | ||
67 | PKT_FIELD(vsk, peer_waiting_write_detected) = false; | |
68 | } | |
69 | return retval; | |
70 | } | |
71 | ||
72 | static void | |
73 | vmci_transport_handle_read(struct sock *sk, | |
74 | struct vmci_transport_packet *pkt, | |
75 | bool bottom_half, | |
76 | struct sockaddr_vm *dst, struct sockaddr_vm *src) | |
77 | { | |
78 | sk->sk_write_space(sk); | |
79 | } | |
80 | ||
81 | static void | |
82 | vmci_transport_handle_wrote(struct sock *sk, | |
83 | struct vmci_transport_packet *pkt, | |
84 | bool bottom_half, | |
85 | struct sockaddr_vm *dst, struct sockaddr_vm *src) | |
86 | { | |
676d2369 | 87 | sk->sk_data_ready(sk); |
d021c344 AK |
88 | } |
89 | ||
90 | static void vsock_block_update_write_window(struct sock *sk) | |
91 | { | |
92 | struct vsock_sock *vsk = vsock_sk(sk); | |
93 | ||
94 | if (PKT_FIELD(vsk, write_notify_window) < vmci_trans(vsk)->consume_size) | |
95 | PKT_FIELD(vsk, write_notify_window) = | |
96 | min(PKT_FIELD(vsk, write_notify_window) + PAGE_SIZE, | |
97 | vmci_trans(vsk)->consume_size); | |
98 | } | |
99 | ||
100 | static int vmci_transport_send_read_notification(struct sock *sk) | |
101 | { | |
102 | struct vsock_sock *vsk; | |
103 | bool sent_read; | |
104 | unsigned int retries; | |
105 | int err; | |
106 | ||
107 | vsk = vsock_sk(sk); | |
108 | sent_read = false; | |
109 | retries = 0; | |
110 | err = 0; | |
111 | ||
112 | if (vmci_transport_notify_waiting_write(vsk)) { | |
113 | /* Notify the peer that we have read, retrying the send on | |
114 | * failure up to our maximum value. XXX For now we just log | |
115 | * the failure, but later we should schedule a work item to | |
116 | * handle the resend until it succeeds. That would require | |
117 | * keeping track of work items in the vsk and cleaning them up | |
118 | * upon socket close. | |
119 | */ | |
120 | while (!(vsk->peer_shutdown & RCV_SHUTDOWN) && | |
121 | !sent_read && | |
122 | retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) { | |
123 | err = vmci_transport_send_read(sk); | |
124 | if (err >= 0) | |
125 | sent_read = true; | |
126 | ||
127 | retries++; | |
128 | } | |
129 | ||
130 | if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_read) | |
131 | pr_err("%p unable to send read notification to peer\n", | |
132 | sk); | |
133 | else | |
134 | PKT_FIELD(vsk, peer_waiting_write) = false; | |
135 | ||
136 | } | |
137 | return err; | |
138 | } | |
139 | ||
140 | static void vmci_transport_notify_pkt_socket_init(struct sock *sk) | |
141 | { | |
142 | struct vsock_sock *vsk = vsock_sk(sk); | |
143 | ||
144 | PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE; | |
145 | PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE; | |
146 | PKT_FIELD(vsk, peer_waiting_write) = false; | |
147 | PKT_FIELD(vsk, peer_waiting_write_detected) = false; | |
148 | } | |
149 | ||
150 | static void vmci_transport_notify_pkt_socket_destruct(struct vsock_sock *vsk) | |
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 int | |
159 | vmci_transport_notify_pkt_poll_in(struct sock *sk, | |
160 | size_t target, bool *data_ready_now) | |
161 | { | |
162 | struct vsock_sock *vsk = vsock_sk(sk); | |
163 | ||
164 | if (vsock_stream_has_data(vsk)) { | |
165 | *data_ready_now = true; | |
166 | } else { | |
167 | /* We can't read right now because there is nothing in the | |
168 | * queue. Ask for notifications when there is something to | |
169 | * read. | |
170 | */ | |
3b4477d2 | 171 | if (sk->sk_state == TCP_ESTABLISHED) |
d021c344 AK |
172 | vsock_block_update_write_window(sk); |
173 | *data_ready_now = false; | |
174 | } | |
175 | ||
176 | return 0; | |
177 | } | |
178 | ||
179 | static int | |
180 | vmci_transport_notify_pkt_poll_out(struct sock *sk, | |
181 | size_t target, bool *space_avail_now) | |
182 | { | |
183 | s64 produce_q_free_space; | |
184 | struct vsock_sock *vsk = vsock_sk(sk); | |
185 | ||
186 | produce_q_free_space = vsock_stream_has_space(vsk); | |
187 | if (produce_q_free_space > 0) { | |
188 | *space_avail_now = true; | |
189 | return 0; | |
190 | } else if (produce_q_free_space == 0) { | |
191 | /* This is a connected socket but we can't currently send data. | |
192 | * Nothing else to do. | |
193 | */ | |
194 | *space_avail_now = false; | |
195 | } | |
196 | ||
197 | return 0; | |
198 | } | |
199 | ||
200 | static int | |
201 | vmci_transport_notify_pkt_recv_init( | |
202 | struct sock *sk, | |
203 | size_t target, | |
204 | struct vmci_transport_recv_notify_data *data) | |
205 | { | |
206 | struct vsock_sock *vsk = vsock_sk(sk); | |
207 | ||
208 | data->consume_head = 0; | |
209 | data->produce_tail = 0; | |
210 | data->notify_on_block = false; | |
211 | ||
212 | if (PKT_FIELD(vsk, write_notify_min_window) < target + 1) { | |
213 | PKT_FIELD(vsk, write_notify_min_window) = target + 1; | |
214 | if (PKT_FIELD(vsk, write_notify_window) < | |
215 | PKT_FIELD(vsk, write_notify_min_window)) { | |
216 | /* If the current window is smaller than the new | |
217 | * minimal window size, we need to reevaluate whether | |
218 | * we need to notify the sender. If the number of ready | |
219 | * bytes are smaller than the new window, we need to | |
220 | * send a notification to the sender before we block. | |
221 | */ | |
222 | ||
223 | PKT_FIELD(vsk, write_notify_window) = | |
224 | PKT_FIELD(vsk, write_notify_min_window); | |
225 | data->notify_on_block = true; | |
226 | } | |
227 | } | |
228 | ||
229 | return 0; | |
230 | } | |
231 | ||
232 | static int | |
233 | vmci_transport_notify_pkt_recv_pre_block( | |
234 | struct sock *sk, | |
235 | size_t target, | |
236 | struct vmci_transport_recv_notify_data *data) | |
237 | { | |
238 | int err = 0; | |
239 | ||
240 | vsock_block_update_write_window(sk); | |
241 | ||
242 | if (data->notify_on_block) { | |
243 | err = vmci_transport_send_read_notification(sk); | |
244 | if (err < 0) | |
245 | return err; | |
246 | data->notify_on_block = false; | |
247 | } | |
248 | ||
249 | return err; | |
250 | } | |
251 | ||
252 | static int | |
253 | vmci_transport_notify_pkt_recv_post_dequeue( | |
254 | struct sock *sk, | |
255 | size_t target, | |
256 | ssize_t copied, | |
257 | bool data_read, | |
258 | struct vmci_transport_recv_notify_data *data) | |
259 | { | |
260 | struct vsock_sock *vsk; | |
261 | int err; | |
262 | bool was_full = false; | |
263 | u64 free_space; | |
264 | ||
265 | vsk = vsock_sk(sk); | |
266 | err = 0; | |
267 | ||
268 | if (data_read) { | |
269 | smp_mb(); | |
270 | ||
271 | free_space = | |
272 | vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair); | |
273 | was_full = free_space == copied; | |
274 | ||
275 | if (was_full) | |
276 | PKT_FIELD(vsk, peer_waiting_write) = true; | |
277 | ||
278 | err = vmci_transport_send_read_notification(sk); | |
279 | if (err < 0) | |
280 | return err; | |
281 | ||
282 | /* See the comment in | |
283 | * vmci_transport_notify_pkt_send_post_enqueue(). | |
284 | */ | |
676d2369 | 285 | sk->sk_data_ready(sk); |
d021c344 AK |
286 | } |
287 | ||
288 | return err; | |
289 | } | |
290 | ||
291 | static int | |
292 | vmci_transport_notify_pkt_send_init( | |
293 | struct sock *sk, | |
294 | struct vmci_transport_send_notify_data *data) | |
295 | { | |
296 | data->consume_head = 0; | |
297 | data->produce_tail = 0; | |
298 | ||
299 | return 0; | |
300 | } | |
301 | ||
302 | static int | |
303 | vmci_transport_notify_pkt_send_post_enqueue( | |
304 | struct sock *sk, | |
305 | ssize_t written, | |
306 | struct vmci_transport_send_notify_data *data) | |
307 | { | |
308 | int err = 0; | |
309 | struct vsock_sock *vsk; | |
310 | bool sent_wrote = false; | |
311 | bool was_empty; | |
312 | int retries = 0; | |
313 | ||
314 | vsk = vsock_sk(sk); | |
315 | ||
316 | smp_mb(); | |
317 | ||
318 | was_empty = | |
319 | vmci_qpair_produce_buf_ready(vmci_trans(vsk)->qpair) == written; | |
320 | if (was_empty) { | |
321 | while (!(vsk->peer_shutdown & RCV_SHUTDOWN) && | |
322 | !sent_wrote && | |
323 | retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) { | |
324 | err = vmci_transport_send_wrote(sk); | |
325 | if (err >= 0) | |
326 | sent_wrote = true; | |
327 | ||
328 | retries++; | |
329 | } | |
330 | } | |
331 | ||
332 | if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_wrote) { | |
333 | pr_err("%p unable to send wrote notification to peer\n", | |
334 | sk); | |
335 | return err; | |
336 | } | |
337 | ||
338 | return err; | |
339 | } | |
340 | ||
341 | static void | |
342 | vmci_transport_notify_pkt_handle_pkt( | |
343 | struct sock *sk, | |
344 | struct vmci_transport_packet *pkt, | |
345 | bool bottom_half, | |
346 | struct sockaddr_vm *dst, | |
347 | struct sockaddr_vm *src, bool *pkt_processed) | |
348 | { | |
349 | bool processed = false; | |
350 | ||
351 | switch (pkt->type) { | |
352 | case VMCI_TRANSPORT_PACKET_TYPE_WROTE: | |
353 | vmci_transport_handle_wrote(sk, pkt, bottom_half, dst, src); | |
354 | processed = true; | |
355 | break; | |
356 | case VMCI_TRANSPORT_PACKET_TYPE_READ: | |
357 | vmci_transport_handle_read(sk, pkt, bottom_half, dst, src); | |
358 | processed = true; | |
359 | break; | |
360 | } | |
361 | ||
362 | if (pkt_processed) | |
363 | *pkt_processed = processed; | |
364 | } | |
365 | ||
366 | static void vmci_transport_notify_pkt_process_request(struct sock *sk) | |
367 | { | |
368 | struct vsock_sock *vsk = vsock_sk(sk); | |
369 | ||
370 | PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size; | |
371 | if (vmci_trans(vsk)->consume_size < | |
372 | PKT_FIELD(vsk, write_notify_min_window)) | |
373 | PKT_FIELD(vsk, write_notify_min_window) = | |
374 | vmci_trans(vsk)->consume_size; | |
375 | } | |
376 | ||
377 | static void vmci_transport_notify_pkt_process_negotiate(struct sock *sk) | |
378 | { | |
379 | struct vsock_sock *vsk = vsock_sk(sk); | |
380 | ||
381 | PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size; | |
382 | if (vmci_trans(vsk)->consume_size < | |
383 | PKT_FIELD(vsk, write_notify_min_window)) | |
384 | PKT_FIELD(vsk, write_notify_min_window) = | |
385 | vmci_trans(vsk)->consume_size; | |
386 | } | |
387 | ||
388 | static int | |
389 | vmci_transport_notify_pkt_recv_pre_dequeue( | |
390 | struct sock *sk, | |
391 | size_t target, | |
392 | struct vmci_transport_recv_notify_data *data) | |
393 | { | |
394 | return 0; /* NOP for QState. */ | |
395 | } | |
396 | ||
397 | static int | |
398 | vmci_transport_notify_pkt_send_pre_block( | |
399 | struct sock *sk, | |
400 | struct vmci_transport_send_notify_data *data) | |
401 | { | |
402 | return 0; /* NOP for QState. */ | |
403 | } | |
404 | ||
405 | static int | |
406 | vmci_transport_notify_pkt_send_pre_enqueue( | |
407 | struct sock *sk, | |
408 | struct vmci_transport_send_notify_data *data) | |
409 | { | |
410 | return 0; /* NOP for QState. */ | |
411 | } | |
412 | ||
413 | /* Socket always on control packet based operations. */ | |
3b22dae3 | 414 | const struct vmci_transport_notify_ops vmci_transport_notify_pkt_q_state_ops = { |
99a5e178 KC |
415 | .socket_init = vmci_transport_notify_pkt_socket_init, |
416 | .socket_destruct = vmci_transport_notify_pkt_socket_destruct, | |
417 | .poll_in = vmci_transport_notify_pkt_poll_in, | |
418 | .poll_out = vmci_transport_notify_pkt_poll_out, | |
419 | .handle_notify_pkt = vmci_transport_notify_pkt_handle_pkt, | |
420 | .recv_init = vmci_transport_notify_pkt_recv_init, | |
421 | .recv_pre_block = vmci_transport_notify_pkt_recv_pre_block, | |
422 | .recv_pre_dequeue = vmci_transport_notify_pkt_recv_pre_dequeue, | |
423 | .recv_post_dequeue = vmci_transport_notify_pkt_recv_post_dequeue, | |
424 | .send_init = vmci_transport_notify_pkt_send_init, | |
425 | .send_pre_block = vmci_transport_notify_pkt_send_pre_block, | |
426 | .send_pre_enqueue = vmci_transport_notify_pkt_send_pre_enqueue, | |
427 | .send_post_enqueue = vmci_transport_notify_pkt_send_post_enqueue, | |
428 | .process_request = vmci_transport_notify_pkt_process_request, | |
429 | .process_negotiate = vmci_transport_notify_pkt_process_negotiate, | |
d021c344 | 430 | }; |