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Commit | Line | Data |
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0a8a69dd RR |
1 | /* Virtio ring implementation. |
2 | * | |
3 | * Copyright 2007 Rusty Russell IBM Corporation | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | */ | |
19 | #include <linux/virtio.h> | |
20 | #include <linux/virtio_ring.h> | |
e34f8725 | 21 | #include <linux/virtio_config.h> |
0a8a69dd | 22 | #include <linux/device.h> |
5a0e3ad6 | 23 | #include <linux/slab.h> |
0a8a69dd | 24 | |
d57ed95d MT |
25 | /* virtio guest is communicating with a virtual "device" that actually runs on |
26 | * a host processor. Memory barriers are used to control SMP effects. */ | |
27 | #ifdef CONFIG_SMP | |
28 | /* Where possible, use SMP barriers which are more lightweight than mandatory | |
29 | * barriers, because mandatory barriers control MMIO effects on accesses | |
30 | * through relaxed memory I/O windows (which virtio does not use). */ | |
31 | #define virtio_mb() smp_mb() | |
32 | #define virtio_rmb() smp_rmb() | |
33 | #define virtio_wmb() smp_wmb() | |
34 | #else | |
35 | /* We must force memory ordering even if guest is UP since host could be | |
36 | * running on another CPU, but SMP barriers are defined to barrier() in that | |
37 | * configuration. So fall back to mandatory barriers instead. */ | |
38 | #define virtio_mb() mb() | |
39 | #define virtio_rmb() rmb() | |
40 | #define virtio_wmb() wmb() | |
41 | #endif | |
42 | ||
0a8a69dd RR |
43 | #ifdef DEBUG |
44 | /* For development, we want to crash whenever the ring is screwed. */ | |
9499f5e7 RR |
45 | #define BAD_RING(_vq, fmt, args...) \ |
46 | do { \ | |
47 | dev_err(&(_vq)->vq.vdev->dev, \ | |
48 | "%s:"fmt, (_vq)->vq.name, ##args); \ | |
49 | BUG(); \ | |
50 | } while (0) | |
c5f841f1 RR |
51 | /* Caller is supposed to guarantee no reentry. */ |
52 | #define START_USE(_vq) \ | |
53 | do { \ | |
54 | if ((_vq)->in_use) \ | |
9499f5e7 RR |
55 | panic("%s:in_use = %i\n", \ |
56 | (_vq)->vq.name, (_vq)->in_use); \ | |
c5f841f1 | 57 | (_vq)->in_use = __LINE__; \ |
9499f5e7 | 58 | } while (0) |
3a35ce7d | 59 | #define END_USE(_vq) \ |
97a545ab | 60 | do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0) |
0a8a69dd | 61 | #else |
9499f5e7 RR |
62 | #define BAD_RING(_vq, fmt, args...) \ |
63 | do { \ | |
64 | dev_err(&_vq->vq.vdev->dev, \ | |
65 | "%s:"fmt, (_vq)->vq.name, ##args); \ | |
66 | (_vq)->broken = true; \ | |
67 | } while (0) | |
0a8a69dd RR |
68 | #define START_USE(vq) |
69 | #define END_USE(vq) | |
70 | #endif | |
71 | ||
72 | struct vring_virtqueue | |
73 | { | |
74 | struct virtqueue vq; | |
75 | ||
76 | /* Actual memory layout for this queue */ | |
77 | struct vring vring; | |
78 | ||
79 | /* Other side has made a mess, don't try any more. */ | |
80 | bool broken; | |
81 | ||
9fa29b9d MM |
82 | /* Host supports indirect buffers */ |
83 | bool indirect; | |
84 | ||
a5c262c5 MT |
85 | /* Host publishes avail event idx */ |
86 | bool event; | |
87 | ||
0a8a69dd RR |
88 | /* Number of free buffers */ |
89 | unsigned int num_free; | |
90 | /* Head of free buffer list. */ | |
91 | unsigned int free_head; | |
92 | /* Number we've added since last sync. */ | |
93 | unsigned int num_added; | |
94 | ||
95 | /* Last used index we've seen. */ | |
1bc4953e | 96 | u16 last_used_idx; |
0a8a69dd RR |
97 | |
98 | /* How to notify other side. FIXME: commonalize hcalls! */ | |
99 | void (*notify)(struct virtqueue *vq); | |
100 | ||
101 | #ifdef DEBUG | |
102 | /* They're supposed to lock for us. */ | |
103 | unsigned int in_use; | |
104 | #endif | |
105 | ||
106 | /* Tokens for callbacks. */ | |
107 | void *data[]; | |
108 | }; | |
109 | ||
110 | #define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq) | |
111 | ||
9fa29b9d MM |
112 | /* Set up an indirect table of descriptors and add it to the queue. */ |
113 | static int vring_add_indirect(struct vring_virtqueue *vq, | |
114 | struct scatterlist sg[], | |
115 | unsigned int out, | |
bbd603ef MT |
116 | unsigned int in, |
117 | gfp_t gfp) | |
9fa29b9d MM |
118 | { |
119 | struct vring_desc *desc; | |
120 | unsigned head; | |
121 | int i; | |
122 | ||
bbd603ef | 123 | desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); |
9fa29b9d | 124 | if (!desc) |
686d3637 | 125 | return -ENOMEM; |
9fa29b9d MM |
126 | |
127 | /* Transfer entries from the sg list into the indirect page */ | |
128 | for (i = 0; i < out; i++) { | |
129 | desc[i].flags = VRING_DESC_F_NEXT; | |
130 | desc[i].addr = sg_phys(sg); | |
131 | desc[i].len = sg->length; | |
132 | desc[i].next = i+1; | |
133 | sg++; | |
134 | } | |
135 | for (; i < (out + in); i++) { | |
136 | desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE; | |
137 | desc[i].addr = sg_phys(sg); | |
138 | desc[i].len = sg->length; | |
139 | desc[i].next = i+1; | |
140 | sg++; | |
141 | } | |
142 | ||
143 | /* Last one doesn't continue. */ | |
144 | desc[i-1].flags &= ~VRING_DESC_F_NEXT; | |
145 | desc[i-1].next = 0; | |
146 | ||
147 | /* We're about to use a buffer */ | |
148 | vq->num_free--; | |
149 | ||
150 | /* Use a single buffer which doesn't continue */ | |
151 | head = vq->free_head; | |
152 | vq->vring.desc[head].flags = VRING_DESC_F_INDIRECT; | |
153 | vq->vring.desc[head].addr = virt_to_phys(desc); | |
154 | vq->vring.desc[head].len = i * sizeof(struct vring_desc); | |
155 | ||
156 | /* Update free pointer */ | |
157 | vq->free_head = vq->vring.desc[head].next; | |
158 | ||
159 | return head; | |
160 | } | |
161 | ||
bbd603ef MT |
162 | int virtqueue_add_buf_gfp(struct virtqueue *_vq, |
163 | struct scatterlist sg[], | |
164 | unsigned int out, | |
165 | unsigned int in, | |
166 | void *data, | |
167 | gfp_t gfp) | |
0a8a69dd RR |
168 | { |
169 | struct vring_virtqueue *vq = to_vvq(_vq); | |
1fe9b6fe MT |
170 | unsigned int i, avail, uninitialized_var(prev); |
171 | int head; | |
0a8a69dd | 172 | |
9fa29b9d MM |
173 | START_USE(vq); |
174 | ||
0a8a69dd | 175 | BUG_ON(data == NULL); |
9fa29b9d MM |
176 | |
177 | /* If the host supports indirect descriptor tables, and we have multiple | |
178 | * buffers, then go indirect. FIXME: tune this threshold */ | |
179 | if (vq->indirect && (out + in) > 1 && vq->num_free) { | |
bbd603ef | 180 | head = vring_add_indirect(vq, sg, out, in, gfp); |
1fe9b6fe | 181 | if (likely(head >= 0)) |
9fa29b9d MM |
182 | goto add_head; |
183 | } | |
184 | ||
0a8a69dd RR |
185 | BUG_ON(out + in > vq->vring.num); |
186 | BUG_ON(out + in == 0); | |
187 | ||
0a8a69dd RR |
188 | if (vq->num_free < out + in) { |
189 | pr_debug("Can't add buf len %i - avail = %i\n", | |
190 | out + in, vq->num_free); | |
44653eae RR |
191 | /* FIXME: for historical reasons, we force a notify here if |
192 | * there are outgoing parts to the buffer. Presumably the | |
193 | * host should service the ring ASAP. */ | |
194 | if (out) | |
195 | vq->notify(&vq->vq); | |
0a8a69dd RR |
196 | END_USE(vq); |
197 | return -ENOSPC; | |
198 | } | |
199 | ||
200 | /* We're about to use some buffers from the free list. */ | |
201 | vq->num_free -= out + in; | |
202 | ||
203 | head = vq->free_head; | |
204 | for (i = vq->free_head; out; i = vq->vring.desc[i].next, out--) { | |
205 | vq->vring.desc[i].flags = VRING_DESC_F_NEXT; | |
15f9c890 | 206 | vq->vring.desc[i].addr = sg_phys(sg); |
0a8a69dd RR |
207 | vq->vring.desc[i].len = sg->length; |
208 | prev = i; | |
209 | sg++; | |
210 | } | |
211 | for (; in; i = vq->vring.desc[i].next, in--) { | |
212 | vq->vring.desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE; | |
15f9c890 | 213 | vq->vring.desc[i].addr = sg_phys(sg); |
0a8a69dd RR |
214 | vq->vring.desc[i].len = sg->length; |
215 | prev = i; | |
216 | sg++; | |
217 | } | |
218 | /* Last one doesn't continue. */ | |
219 | vq->vring.desc[prev].flags &= ~VRING_DESC_F_NEXT; | |
220 | ||
221 | /* Update free pointer */ | |
222 | vq->free_head = i; | |
223 | ||
9fa29b9d | 224 | add_head: |
0a8a69dd RR |
225 | /* Set token. */ |
226 | vq->data[head] = data; | |
227 | ||
228 | /* Put entry in available array (but don't update avail->idx until they | |
229 | * do sync). FIXME: avoid modulus here? */ | |
230 | avail = (vq->vring.avail->idx + vq->num_added++) % vq->vring.num; | |
231 | vq->vring.avail->ring[avail] = head; | |
232 | ||
233 | pr_debug("Added buffer head %i to %p\n", head, vq); | |
234 | END_USE(vq); | |
3c1b27d5 | 235 | |
3c1b27d5 | 236 | return vq->num_free; |
0a8a69dd | 237 | } |
bbd603ef | 238 | EXPORT_SYMBOL_GPL(virtqueue_add_buf_gfp); |
0a8a69dd | 239 | |
7c5e9ed0 | 240 | void virtqueue_kick(struct virtqueue *_vq) |
0a8a69dd RR |
241 | { |
242 | struct vring_virtqueue *vq = to_vvq(_vq); | |
a5c262c5 | 243 | u16 new, old; |
0a8a69dd RR |
244 | START_USE(vq); |
245 | /* Descriptors and available array need to be set before we expose the | |
246 | * new available array entries. */ | |
d57ed95d | 247 | virtio_wmb(); |
0a8a69dd | 248 | |
a5c262c5 MT |
249 | old = vq->vring.avail->idx; |
250 | new = vq->vring.avail->idx = old + vq->num_added; | |
0a8a69dd RR |
251 | vq->num_added = 0; |
252 | ||
253 | /* Need to update avail index before checking if we should notify */ | |
d57ed95d | 254 | virtio_mb(); |
0a8a69dd | 255 | |
a5c262c5 MT |
256 | if (vq->event ? |
257 | vring_need_event(vring_avail_event(&vq->vring), new, old) : | |
258 | !(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY)) | |
0a8a69dd RR |
259 | /* Prod other side to tell it about changes. */ |
260 | vq->notify(&vq->vq); | |
261 | ||
262 | END_USE(vq); | |
263 | } | |
7c5e9ed0 | 264 | EXPORT_SYMBOL_GPL(virtqueue_kick); |
0a8a69dd RR |
265 | |
266 | static void detach_buf(struct vring_virtqueue *vq, unsigned int head) | |
267 | { | |
268 | unsigned int i; | |
269 | ||
270 | /* Clear data ptr. */ | |
271 | vq->data[head] = NULL; | |
272 | ||
273 | /* Put back on free list: find end */ | |
274 | i = head; | |
9fa29b9d MM |
275 | |
276 | /* Free the indirect table */ | |
277 | if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) | |
278 | kfree(phys_to_virt(vq->vring.desc[i].addr)); | |
279 | ||
0a8a69dd RR |
280 | while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) { |
281 | i = vq->vring.desc[i].next; | |
282 | vq->num_free++; | |
283 | } | |
284 | ||
285 | vq->vring.desc[i].next = vq->free_head; | |
286 | vq->free_head = head; | |
287 | /* Plus final descriptor */ | |
288 | vq->num_free++; | |
289 | } | |
290 | ||
0a8a69dd RR |
291 | static inline bool more_used(const struct vring_virtqueue *vq) |
292 | { | |
293 | return vq->last_used_idx != vq->vring.used->idx; | |
294 | } | |
295 | ||
7c5e9ed0 | 296 | void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) |
0a8a69dd RR |
297 | { |
298 | struct vring_virtqueue *vq = to_vvq(_vq); | |
299 | void *ret; | |
300 | unsigned int i; | |
301 | ||
302 | START_USE(vq); | |
303 | ||
5ef82752 RR |
304 | if (unlikely(vq->broken)) { |
305 | END_USE(vq); | |
306 | return NULL; | |
307 | } | |
308 | ||
0a8a69dd RR |
309 | if (!more_used(vq)) { |
310 | pr_debug("No more buffers in queue\n"); | |
311 | END_USE(vq); | |
312 | return NULL; | |
313 | } | |
314 | ||
2d61ba95 | 315 | /* Only get used array entries after they have been exposed by host. */ |
d57ed95d | 316 | virtio_rmb(); |
2d61ba95 | 317 | |
0a8a69dd RR |
318 | i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id; |
319 | *len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].len; | |
320 | ||
321 | if (unlikely(i >= vq->vring.num)) { | |
322 | BAD_RING(vq, "id %u out of range\n", i); | |
323 | return NULL; | |
324 | } | |
325 | if (unlikely(!vq->data[i])) { | |
326 | BAD_RING(vq, "id %u is not a head!\n", i); | |
327 | return NULL; | |
328 | } | |
329 | ||
330 | /* detach_buf clears data, so grab it now. */ | |
331 | ret = vq->data[i]; | |
332 | detach_buf(vq, i); | |
333 | vq->last_used_idx++; | |
a5c262c5 MT |
334 | /* If we expect an interrupt for the next entry, tell host |
335 | * by writing event index and flush out the write before | |
336 | * the read in the next get_buf call. */ | |
337 | if (!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) { | |
338 | vring_used_event(&vq->vring) = vq->last_used_idx; | |
339 | virtio_mb(); | |
340 | } | |
341 | ||
0a8a69dd RR |
342 | END_USE(vq); |
343 | return ret; | |
344 | } | |
7c5e9ed0 | 345 | EXPORT_SYMBOL_GPL(virtqueue_get_buf); |
0a8a69dd | 346 | |
7c5e9ed0 | 347 | void virtqueue_disable_cb(struct virtqueue *_vq) |
18445c4d RR |
348 | { |
349 | struct vring_virtqueue *vq = to_vvq(_vq); | |
350 | ||
18445c4d | 351 | vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT; |
18445c4d | 352 | } |
7c5e9ed0 | 353 | EXPORT_SYMBOL_GPL(virtqueue_disable_cb); |
18445c4d | 354 | |
7c5e9ed0 | 355 | bool virtqueue_enable_cb(struct virtqueue *_vq) |
0a8a69dd RR |
356 | { |
357 | struct vring_virtqueue *vq = to_vvq(_vq); | |
358 | ||
359 | START_USE(vq); | |
0a8a69dd RR |
360 | |
361 | /* We optimistically turn back on interrupts, then check if there was | |
362 | * more to do. */ | |
a5c262c5 MT |
363 | /* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to |
364 | * either clear the flags bit or point the event index at the next | |
365 | * entry. Always do both to keep code simple. */ | |
0a8a69dd | 366 | vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT; |
a5c262c5 | 367 | vring_used_event(&vq->vring) = vq->last_used_idx; |
d57ed95d | 368 | virtio_mb(); |
0a8a69dd | 369 | if (unlikely(more_used(vq))) { |
0a8a69dd RR |
370 | END_USE(vq); |
371 | return false; | |
372 | } | |
373 | ||
374 | END_USE(vq); | |
375 | return true; | |
376 | } | |
7c5e9ed0 | 377 | EXPORT_SYMBOL_GPL(virtqueue_enable_cb); |
0a8a69dd | 378 | |
7ab358c2 MT |
379 | bool virtqueue_enable_cb_delayed(struct virtqueue *_vq) |
380 | { | |
381 | struct vring_virtqueue *vq = to_vvq(_vq); | |
382 | u16 bufs; | |
383 | ||
384 | START_USE(vq); | |
385 | ||
386 | /* We optimistically turn back on interrupts, then check if there was | |
387 | * more to do. */ | |
388 | /* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to | |
389 | * either clear the flags bit or point the event index at the next | |
390 | * entry. Always do both to keep code simple. */ | |
391 | vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT; | |
392 | /* TODO: tune this threshold */ | |
393 | bufs = (u16)(vq->vring.avail->idx - vq->last_used_idx) * 3 / 4; | |
394 | vring_used_event(&vq->vring) = vq->last_used_idx + bufs; | |
395 | virtio_mb(); | |
396 | if (unlikely((u16)(vq->vring.used->idx - vq->last_used_idx) > bufs)) { | |
397 | END_USE(vq); | |
398 | return false; | |
399 | } | |
400 | ||
401 | END_USE(vq); | |
402 | return true; | |
403 | } | |
404 | EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed); | |
405 | ||
7c5e9ed0 | 406 | void *virtqueue_detach_unused_buf(struct virtqueue *_vq) |
c021eac4 SM |
407 | { |
408 | struct vring_virtqueue *vq = to_vvq(_vq); | |
409 | unsigned int i; | |
410 | void *buf; | |
411 | ||
412 | START_USE(vq); | |
413 | ||
414 | for (i = 0; i < vq->vring.num; i++) { | |
415 | if (!vq->data[i]) | |
416 | continue; | |
417 | /* detach_buf clears data, so grab it now. */ | |
418 | buf = vq->data[i]; | |
419 | detach_buf(vq, i); | |
b3258ff1 | 420 | vq->vring.avail->idx--; |
c021eac4 SM |
421 | END_USE(vq); |
422 | return buf; | |
423 | } | |
424 | /* That should have freed everything. */ | |
425 | BUG_ON(vq->num_free != vq->vring.num); | |
426 | ||
427 | END_USE(vq); | |
428 | return NULL; | |
429 | } | |
7c5e9ed0 | 430 | EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf); |
c021eac4 | 431 | |
0a8a69dd RR |
432 | irqreturn_t vring_interrupt(int irq, void *_vq) |
433 | { | |
434 | struct vring_virtqueue *vq = to_vvq(_vq); | |
435 | ||
436 | if (!more_used(vq)) { | |
437 | pr_debug("virtqueue interrupt with no work for %p\n", vq); | |
438 | return IRQ_NONE; | |
439 | } | |
440 | ||
441 | if (unlikely(vq->broken)) | |
442 | return IRQ_HANDLED; | |
443 | ||
444 | pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback); | |
18445c4d RR |
445 | if (vq->vq.callback) |
446 | vq->vq.callback(&vq->vq); | |
0a8a69dd RR |
447 | |
448 | return IRQ_HANDLED; | |
449 | } | |
c6fd4701 | 450 | EXPORT_SYMBOL_GPL(vring_interrupt); |
0a8a69dd | 451 | |
0a8a69dd | 452 | struct virtqueue *vring_new_virtqueue(unsigned int num, |
87c7d57c | 453 | unsigned int vring_align, |
0a8a69dd RR |
454 | struct virtio_device *vdev, |
455 | void *pages, | |
456 | void (*notify)(struct virtqueue *), | |
9499f5e7 RR |
457 | void (*callback)(struct virtqueue *), |
458 | const char *name) | |
0a8a69dd RR |
459 | { |
460 | struct vring_virtqueue *vq; | |
461 | unsigned int i; | |
462 | ||
42b36cc0 RR |
463 | /* We assume num is a power of 2. */ |
464 | if (num & (num - 1)) { | |
465 | dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); | |
466 | return NULL; | |
467 | } | |
468 | ||
0a8a69dd RR |
469 | vq = kmalloc(sizeof(*vq) + sizeof(void *)*num, GFP_KERNEL); |
470 | if (!vq) | |
471 | return NULL; | |
472 | ||
87c7d57c | 473 | vring_init(&vq->vring, num, pages, vring_align); |
0a8a69dd RR |
474 | vq->vq.callback = callback; |
475 | vq->vq.vdev = vdev; | |
9499f5e7 | 476 | vq->vq.name = name; |
0a8a69dd RR |
477 | vq->notify = notify; |
478 | vq->broken = false; | |
479 | vq->last_used_idx = 0; | |
480 | vq->num_added = 0; | |
9499f5e7 | 481 | list_add_tail(&vq->vq.list, &vdev->vqs); |
0a8a69dd RR |
482 | #ifdef DEBUG |
483 | vq->in_use = false; | |
484 | #endif | |
485 | ||
9fa29b9d | 486 | vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC); |
a5c262c5 | 487 | vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); |
9fa29b9d | 488 | |
0a8a69dd RR |
489 | /* No callback? Tell other side not to bother us. */ |
490 | if (!callback) | |
491 | vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT; | |
492 | ||
493 | /* Put everything in free lists. */ | |
494 | vq->num_free = num; | |
495 | vq->free_head = 0; | |
3b870624 | 496 | for (i = 0; i < num-1; i++) { |
0a8a69dd | 497 | vq->vring.desc[i].next = i+1; |
3b870624 AS |
498 | vq->data[i] = NULL; |
499 | } | |
500 | vq->data[i] = NULL; | |
0a8a69dd RR |
501 | |
502 | return &vq->vq; | |
503 | } | |
c6fd4701 | 504 | EXPORT_SYMBOL_GPL(vring_new_virtqueue); |
0a8a69dd RR |
505 | |
506 | void vring_del_virtqueue(struct virtqueue *vq) | |
507 | { | |
9499f5e7 | 508 | list_del(&vq->list); |
0a8a69dd RR |
509 | kfree(to_vvq(vq)); |
510 | } | |
c6fd4701 | 511 | EXPORT_SYMBOL_GPL(vring_del_virtqueue); |
0a8a69dd | 512 | |
e34f8725 RR |
513 | /* Manipulates transport-specific feature bits. */ |
514 | void vring_transport_features(struct virtio_device *vdev) | |
515 | { | |
516 | unsigned int i; | |
517 | ||
518 | for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) { | |
519 | switch (i) { | |
9fa29b9d MM |
520 | case VIRTIO_RING_F_INDIRECT_DESC: |
521 | break; | |
a5c262c5 MT |
522 | case VIRTIO_RING_F_EVENT_IDX: |
523 | break; | |
e34f8725 RR |
524 | default: |
525 | /* We don't understand this bit. */ | |
526 | clear_bit(i, vdev->features); | |
527 | } | |
528 | } | |
529 | } | |
530 | EXPORT_SYMBOL_GPL(vring_transport_features); | |
531 | ||
8f9f4668 RJ |
532 | /* return the size of the vring within the virtqueue */ |
533 | unsigned int virtqueue_get_vring_size(struct virtqueue *_vq) | |
534 | { | |
535 | ||
536 | struct vring_virtqueue *vq = to_vvq(_vq); | |
537 | ||
538 | return vq->vring.num; | |
539 | } | |
540 | EXPORT_SYMBOL_GPL(virtqueue_get_vring_size); | |
541 | ||
c6fd4701 | 542 | MODULE_LICENSE("GPL"); |