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authorPaolo Bonzini <pbonzini@redhat.com>2012-05-08 16:51:45 +0200
committerKevin Wolf <kwolf@redhat.com>2012-05-10 10:32:12 +0200
commit4513eafe928ff47486f4167c28d364c72b5ff7e3 (patch)
tree8976dece72550042799603af6c51c8835fcf0087
parent0ac9377d043e03350b1ff8e21b927598c02fc7fb (diff)
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block: add block_job_sleep_ns
This function abstracts the pretty complex semantics of the "busy" member of BlockJob. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block.c11
-rw-r--r--block/stream.c23
-rw-r--r--block_int.h22
3 files changed, 35 insertions, 21 deletions
diff --git a/block.c b/block.c
index 6154c3f..f9a11aa 100644
--- a/block.c
+++ b/block.c
@@ -4188,6 +4188,7 @@ void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
job->bs = bs;
job->cb = cb;
job->opaque = opaque;
+ job->busy = true;
bs->job = job;
/* Only set speed when necessary to avoid NotSupported error */
@@ -4254,3 +4255,13 @@ void block_job_cancel_sync(BlockJob *job)
qemu_aio_wait();
}
}
+
+void block_job_sleep_ns(BlockJob *job, QEMUClock *clock, int64_t ns)
+{
+ /* Check cancellation *before* setting busy = false, too! */
+ if (!block_job_is_cancelled(job)) {
+ job->busy = false;
+ co_sleep_ns(clock, ns);
+ job->busy = true;
+ }
+}
diff --git a/block/stream.c b/block/stream.c
index b7e1ad4..b279acd 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -192,12 +192,17 @@ static void coroutine_fn stream_run(void *opaque)
}
for (sector_num = 0; sector_num < end; sector_num += n) {
-retry:
+ uint64_t delay_ns = 0;
+
+wait:
+ /* Note that even when no rate limit is applied we need to yield
+ * with no pending I/O here so that qemu_aio_flush() returns.
+ */
+ block_job_sleep_ns(&s->common, rt_clock, delay_ns);
if (block_job_is_cancelled(&s->common)) {
break;
}
- s->common.busy = true;
if (base) {
ret = is_allocated_base(bs, base, sector_num,
STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n);
@@ -209,13 +214,9 @@ retry:
trace_stream_one_iteration(s, sector_num, n, ret);
if (ret == 0) {
if (s->common.speed) {
- uint64_t delay_ns = ratelimit_calculate_delay(&s->limit, n);
+ delay_ns = ratelimit_calculate_delay(&s->limit, n);
if (delay_ns > 0) {
- s->common.busy = false;
- co_sleep_ns(rt_clock, delay_ns);
-
- /* Recheck cancellation and that sectors are unallocated */
- goto retry;
+ goto wait;
}
}
ret = stream_populate(bs, sector_num, n, buf);
@@ -227,12 +228,6 @@ retry:
/* Publish progress */
s->common.offset += n * BDRV_SECTOR_SIZE;
-
- /* Note that even when no rate limit is applied we need to yield
- * with no pending I/O here so that qemu_aio_flush() returns.
- */
- s->common.busy = false;
- co_sleep_ns(rt_clock, 0);
}
if (!base) {
diff --git a/block_int.h b/block_int.h
index fbbc7ae..3bf2367 100644
--- a/block_int.h
+++ b/block_int.h
@@ -97,18 +97,15 @@ struct BlockJob {
/**
* Set to true if the job should cancel itself. The flag must
* always be tested just before toggling the busy flag from false
- * to true. After a job has detected that the cancelled flag is
- * true, it should not anymore issue any I/O operation to the
- * block device.
+ * to true. After a job has been cancelled, it should only yield
+ * if #qemu_aio_wait will ("sooner or later") reenter the coroutine.
*/
bool cancelled;
/**
* Set to false by the job while it is in a quiescent state, where
- * no I/O is pending and cancellation can be processed without
- * issuing new I/O. The busy flag must be set to false when the
- * job goes to sleep on any condition that is not detected by
- * #qemu_aio_wait, such as a timer.
+ * no I/O is pending and the job has yielded on any condition
+ * that is not detected by #qemu_aio_wait, such as a timer.
*/
bool busy;
@@ -364,6 +361,17 @@ void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
void *opaque, Error **errp);
/**
+ * block_job_sleep_ns:
+ * @job: The job that calls the function.
+ * @clock: The clock to sleep on.
+ * @ns: How many nanoseconds to stop for.
+ *
+ * Put the job to sleep (assuming that it wasn't canceled) for @ns
+ * nanoseconds. Canceling the job will interrupt the wait immediately.
+ */
+void block_job_sleep_ns(BlockJob *job, QEMUClock *clock, int64_t ns);
+
+/**
* block_job_complete:
* @job: The job being completed.
* @ret: The status code.