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-rw-r--r--block/blkio.c2
-rw-r--r--hw/block/dataplane/virtio-blk.c17
-rw-r--r--hw/block/virtio-blk.c44
-rw-r--r--include/hw/virtio/virtio-blk.h2
-rw-r--r--util/aio-posix.c21
5 files changed, 42 insertions, 44 deletions
diff --git a/block/blkio.c b/block/blkio.c
index 5eae3adfaf..6ad86b23d1 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -19,6 +19,8 @@
#include "qemu/module.h"
#include "exec/memory.h" /* for ram_block_discard_disable() */
+#include "block/block-io.h"
+
/*
* Keep the QEMU BlockDriver names identical to the libblkio driver names.
* Using macros instead of typing out the string literals avoids typos.
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 26f965cabc..b28d81737e 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -237,9 +237,6 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
goto fail_aio_context;
}
- /* Process queued requests before the ones in vring */
- virtio_blk_process_queued_requests(vblk, false);
-
/* Kick right away to begin processing requests already in vring */
for (i = 0; i < nvqs; i++) {
VirtQueue *vq = virtio_get_queue(s->vdev, i);
@@ -272,11 +269,6 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
fail_host_notifiers:
k->set_guest_notifiers(qbus->parent, nvqs, false);
fail_guest_notifiers:
- /*
- * If we failed to set up the guest notifiers queued requests will be
- * processed on the main context.
- */
- virtio_blk_process_queued_requests(vblk, false);
vblk->dataplane_disabled = true;
s->starting = false;
vblk->dataplane_started = true;
@@ -325,8 +317,13 @@ void virtio_blk_data_plane_stop(VirtIODevice *vdev)
aio_context_acquire(s->ctx);
aio_wait_bh_oneshot(s->ctx, virtio_blk_data_plane_stop_bh, s);
- /* Drain and try to switch bs back to the QEMU main loop. If other users
- * keep the BlockBackend in the iothread, that's ok */
+ /* Wait for virtio_blk_dma_restart_bh() and in flight I/O to complete */
+ blk_drain(s->conf->conf.blk);
+
+ /*
+ * Try to switch bs back to the QEMU main loop. If other users keep the
+ * BlockBackend in the iothread, that's ok
+ */
blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context(), NULL);
aio_context_release(s->ctx);
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index f717550fdc..1762517878 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -806,8 +806,10 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
virtio_blk_handle_vq(s, vq);
}
-void virtio_blk_process_queued_requests(VirtIOBlock *s, bool is_bh)
+static void virtio_blk_dma_restart_bh(void *opaque)
{
+ VirtIOBlock *s = opaque;
+
VirtIOBlockReq *req = s->rq;
MultiReqBuffer mrb = {};
@@ -834,43 +836,27 @@ void virtio_blk_process_queued_requests(VirtIOBlock *s, bool is_bh)
if (mrb.num_reqs) {
virtio_blk_submit_multireq(s, &mrb);
}
- if (is_bh) {
- blk_dec_in_flight(s->conf.conf.blk);
- }
- aio_context_release(blk_get_aio_context(s->conf.conf.blk));
-}
-
-static void virtio_blk_dma_restart_bh(void *opaque)
-{
- VirtIOBlock *s = opaque;
- qemu_bh_delete(s->bh);
- s->bh = NULL;
+ /* Paired with inc in virtio_blk_dma_restart_cb() */
+ blk_dec_in_flight(s->conf.conf.blk);
- virtio_blk_process_queued_requests(s, true);
+ aio_context_release(blk_get_aio_context(s->conf.conf.blk));
}
static void virtio_blk_dma_restart_cb(void *opaque, bool running,
RunState state)
{
VirtIOBlock *s = opaque;
- BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
- VirtioBusState *bus = VIRTIO_BUS(qbus);
if (!running) {
return;
}
- /*
- * If ioeventfd is enabled, don't schedule the BH here as queued
- * requests will be processed while starting the data plane.
- */
- if (!s->bh && !virtio_bus_ioeventfd_enabled(bus)) {
- s->bh = aio_bh_new(blk_get_aio_context(s->conf.conf.blk),
- virtio_blk_dma_restart_bh, s);
- blk_inc_in_flight(s->conf.conf.blk);
- qemu_bh_schedule(s->bh);
- }
+ /* Paired with dec in virtio_blk_dma_restart_bh() */
+ blk_inc_in_flight(s->conf.conf.blk);
+
+ aio_bh_schedule_oneshot(blk_get_aio_context(s->conf.conf.blk),
+ virtio_blk_dma_restart_bh, s);
}
static void virtio_blk_reset(VirtIODevice *vdev)
@@ -1213,7 +1199,13 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
return;
}
- s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
+ /*
+ * This must be after virtio_init() so virtio_blk_dma_restart_cb() gets
+ * called after ->start_ioeventfd() has already set blk's AioContext.
+ */
+ s->change =
+ qdev_add_vm_change_state_handler(dev, virtio_blk_dma_restart_cb, s);
+
blk_ram_registrar_init(&s->blk_ram_registrar, s->blk);
blk_set_dev_ops(s->blk, &virtio_block_ops, s);
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 7f589b4146..dafec432ce 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -55,7 +55,6 @@ struct VirtIOBlock {
VirtIODevice parent_obj;
BlockBackend *blk;
void *rq;
- QEMUBH *bh;
VirtIOBlkConf conf;
unsigned short sector_mask;
bool original_wce;
@@ -93,6 +92,5 @@ typedef struct MultiReqBuffer {
} MultiReqBuffer;
void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq);
-void virtio_blk_process_queued_requests(VirtIOBlock *s, bool is_bh);
#endif
diff --git a/util/aio-posix.c b/util/aio-posix.c
index 731f3826c0..6cc6256d53 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -585,18 +585,16 @@ static bool try_poll_mode(AioContext *ctx, AioHandlerList *ready_list,
max_ns = qemu_soonest_timeout(*timeout, ctx->poll_ns);
if (max_ns && !ctx->fdmon_ops->need_wait(ctx)) {
+ /*
+ * Enable poll mode. It pairs with the poll_set_started() in
+ * aio_poll() which disables poll mode.
+ */
poll_set_started(ctx, ready_list, true);
if (run_poll_handlers(ctx, ready_list, max_ns, timeout)) {
return true;
}
}
-
- if (poll_set_started(ctx, ready_list, false)) {
- *timeout = 0;
- return true;
- }
-
return false;
}
@@ -657,6 +655,17 @@ bool aio_poll(AioContext *ctx, bool blocking)
* system call---a single round of run_poll_handlers_once suffices.
*/
if (timeout || ctx->fdmon_ops->need_wait(ctx)) {
+ /*
+ * Disable poll mode. poll mode should be disabled before the call
+ * of ctx->fdmon_ops->wait() so that guest's notification can wake
+ * up IO threads when some work becomes pending. It is essential to
+ * avoid hangs or unnecessary latency.
+ */
+ if (poll_set_started(ctx, &ready_list, false)) {
+ timeout = 0;
+ progress = true;
+ }
+
ctx->fdmon_ops->wait(ctx, &ready_list, timeout);
}
generated by cgit v1.2.3 (git 2.26.2) at 2025-03-21 21:47:41 +0000