diff options
Diffstat (limited to 'block/io.c')
| -rw-r--r-- | block/io.c | 51 |
1 files changed, 31 insertions, 20 deletions
@@ -130,13 +130,13 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) */ void bdrv_enable_copy_on_read(BlockDriverState *bs) { - bs->copy_on_read++; + atomic_inc(&bs->copy_on_read); } void bdrv_disable_copy_on_read(BlockDriverState *bs) { - assert(bs->copy_on_read > 0); - bs->copy_on_read--; + int old = atomic_fetch_dec(&bs->copy_on_read); + assert(old >= 1); } /* Check if any requests are in-flight (including throttled requests) */ @@ -241,7 +241,7 @@ void bdrv_drained_begin(BlockDriverState *bs) return; } - if (!bs->quiesce_counter++) { + if (atomic_fetch_inc(&bs->quiesce_counter) == 0) { aio_disable_external(bdrv_get_aio_context(bs)); bdrv_parent_drained_begin(bs); } @@ -252,7 +252,7 @@ void bdrv_drained_begin(BlockDriverState *bs) void bdrv_drained_end(BlockDriverState *bs) { assert(bs->quiesce_counter > 0); - if (--bs->quiesce_counter > 0) { + if (atomic_fetch_dec(&bs->quiesce_counter) > 1) { return; } @@ -375,11 +375,13 @@ void bdrv_drain_all(void) static void tracked_request_end(BdrvTrackedRequest *req) { if (req->serialising) { - req->bs->serialising_in_flight--; + atomic_dec(&req->bs->serialising_in_flight); } + qemu_co_mutex_lock(&req->bs->reqs_lock); QLIST_REMOVE(req, list); qemu_co_queue_restart_all(&req->wait_queue); + qemu_co_mutex_unlock(&req->bs->reqs_lock); } /** @@ -404,7 +406,9 @@ static void tracked_request_begin(BdrvTrackedRequest *req, qemu_co_queue_init(&req->wait_queue); + qemu_co_mutex_lock(&bs->reqs_lock); QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); + qemu_co_mutex_unlock(&bs->reqs_lock); } static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) @@ -414,7 +418,7 @@ static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) - overlap_offset; if (!req->serialising) { - req->bs->serialising_in_flight++; + atomic_inc(&req->bs->serialising_in_flight); req->serialising = true; } @@ -501,7 +505,8 @@ static void dummy_bh_cb(void *opaque) void bdrv_wakeup(BlockDriverState *bs) { - if (bs->wakeup) { + /* The barrier (or an atomic op) is in the caller. */ + if (atomic_read(&bs->wakeup)) { aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL); } } @@ -519,12 +524,13 @@ static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) bool retry; bool waited = false; - if (!bs->serialising_in_flight) { + if (!atomic_read(&bs->serialising_in_flight)) { return false; } do { retry = false; + qemu_co_mutex_lock(&bs->reqs_lock); QLIST_FOREACH(req, &bs->tracked_requests, list) { if (req == self || (!req->serialising && !self->serialising)) { continue; @@ -543,7 +549,7 @@ static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) * (instead of producing a deadlock in the former case). */ if (!req->waiting_for) { self->waiting_for = req; - qemu_co_queue_wait(&req->wait_queue, NULL); + qemu_co_queue_wait(&req->wait_queue, &bs->reqs_lock); self->waiting_for = NULL; retry = true; waited = true; @@ -551,6 +557,7 @@ static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) } } } + qemu_co_mutex_unlock(&bs->reqs_lock); } while (retry); return waited; @@ -1144,7 +1151,7 @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child, bdrv_inc_in_flight(bs); /* Don't do copy-on-read if we read data before write operation */ - if (bs->copy_on_read && !(flags & BDRV_REQ_NO_SERIALISING)) { + if (atomic_read(&bs->copy_on_read) && !(flags & BDRV_REQ_NO_SERIALISING)) { flags |= BDRV_REQ_COPY_ON_READ; } @@ -1401,12 +1408,10 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child, } bdrv_debug_event(bs, BLKDBG_PWRITEV_DONE); - ++bs->write_gen; + atomic_inc(&bs->write_gen); bdrv_set_dirty(bs, start_sector, end_sector - start_sector); - if (bs->wr_highest_offset < offset + bytes) { - bs->wr_highest_offset = offset + bytes; - } + stat64_max(&bs->wr_highest_offset, offset + bytes); if (ret >= 0) { bs->total_sectors = MAX(bs->total_sectors, end_sector); @@ -2292,14 +2297,17 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs) goto early_exit; } - current_gen = bs->write_gen; + qemu_co_mutex_lock(&bs->reqs_lock); + current_gen = atomic_read(&bs->write_gen); /* Wait until any previous flushes are completed */ while (bs->active_flush_req) { - qemu_co_queue_wait(&bs->flush_queue, NULL); + qemu_co_queue_wait(&bs->flush_queue, &bs->reqs_lock); } + /* Flushes reach this point in nondecreasing current_gen order. */ bs->active_flush_req = true; + qemu_co_mutex_unlock(&bs->reqs_lock); /* Write back all layers by calling one driver function */ if (bs->drv->bdrv_co_flush) { @@ -2371,9 +2379,12 @@ out: if (ret == 0) { bs->flushed_gen = current_gen; } + + qemu_co_mutex_lock(&bs->reqs_lock); bs->active_flush_req = false; /* Return value is ignored - it's ok if wait queue is empty */ qemu_co_queue_next(&bs->flush_queue); + qemu_co_mutex_unlock(&bs->reqs_lock); early_exit: bdrv_dec_in_flight(bs); @@ -2517,7 +2528,7 @@ int coroutine_fn bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, } ret = 0; out: - ++bs->write_gen; + atomic_inc(&bs->write_gen); bdrv_set_dirty(bs, req.offset >> BDRV_SECTOR_BITS, req.bytes >> BDRV_SECTOR_BITS); tracked_request_end(&req); @@ -2644,7 +2655,7 @@ void bdrv_io_plug(BlockDriverState *bs) bdrv_io_plug(child->bs); } - if (bs->io_plugged++ == 0) { + if (atomic_fetch_inc(&bs->io_plugged) == 0) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_io_plug) { drv->bdrv_io_plug(bs); @@ -2657,7 +2668,7 @@ void bdrv_io_unplug(BlockDriverState *bs) BdrvChild *child; assert(bs->io_plugged); - if (--bs->io_plugged == 0) { + if (atomic_fetch_dec(&bs->io_plugged) == 1) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_io_unplug) { drv->bdrv_io_unplug(bs); |