| … | |
… | |
| 231 | if (ecb_expect_false (ring->magic != AIO_RING_MAGIC) |
231 | if (ecb_expect_false (ring->magic != AIO_RING_MAGIC) |
| 232 | || ring->incompat_features != AIO_RING_INCOMPAT_FEATURES |
232 | || ring->incompat_features != AIO_RING_INCOMPAT_FEATURES |
| 233 | || ring->header_length != sizeof (struct aio_ring)) /* TODO: or use it to find io_event[0]? */ |
233 | || ring->header_length != sizeof (struct aio_ring)) /* TODO: or use it to find io_event[0]? */ |
| 234 | return 0; |
234 | return 0; |
| 235 | |
235 | |
|
|
236 | /* make sure the events up to tail are visible */ |
| 236 | ECB_MEMORY_FENCE_ACQUIRE; |
237 | ECB_MEMORY_FENCE_ACQUIRE; |
| 237 | |
238 | |
| 238 | /* parse all available events, but only once, to avoid starvation */ |
239 | /* parse all available events, but only once, to avoid starvation */ |
| 239 | if (tail > head) /* normal case around */ |
240 | if (tail > head) /* normal case around */ |
| 240 | linuxaio_parse_events (EV_A_ ring->io_events + head, tail - head); |
241 | linuxaio_parse_events (EV_A_ ring->io_events + head, tail - head); |
| … | |
… | |
| 243 | linuxaio_parse_events (EV_A_ ring->io_events + head, ring->nr - head); |
244 | linuxaio_parse_events (EV_A_ ring->io_events + head, ring->nr - head); |
| 244 | linuxaio_parse_events (EV_A_ ring->io_events, tail); |
245 | linuxaio_parse_events (EV_A_ ring->io_events, tail); |
| 245 | } |
246 | } |
| 246 | |
247 | |
| 247 | *(volatile unsigned *)&ring->head = tail; |
248 | *(volatile unsigned *)&ring->head = tail; |
| 248 | |
249 | /* make sure kernel can see our new head value - probably not required */ |
| 249 | /* again, other implementations don't do this, but I think it's required for the kernel to see free slots */ |
|
|
| 250 | ECB_MEMORY_FENCE_RELEASE; |
250 | ECB_MEMORY_FENCE_RELEASE; |
| 251 | |
251 | |
| 252 | return 1; |
252 | return 1; |
| 253 | } |
253 | } |
| 254 | |
254 | |
