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block: add block_job_sleep_ns

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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>
This commit is contained in:
Paolo Bonzini 2012-05-08 16:51:45 +02:00 committed by Kevin Wolf
parent 0ac9377d04
commit 4513eafe92
3 changed files with 35 additions and 21 deletions
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11
block.c
View file

@ -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;
}
}

23
block/stream.c
View file

@ -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) {

22
block_int.h
View file

@ -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;
@ -363,6 +360,17 @@ void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
int64_t speed, BlockDriverCompletionFunc *cb,
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.