blockjob: add AioContext attached callback

Block jobs that use additional BDSes or event loop resources need a
callback to get their affairs in order when the AioContext is switched.

Simple block jobs don't need an attach callback, they automatically work
thanks to the generic attach/detach notifiers that this patch adds.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1466096189-6477-7-git-send-email-stefanha@redhat.com
stable-2.7
Stefan Hajnoczi 2016-06-16 17:56:27 +01:00
parent e8a095dadb
commit 463e0be101
2 changed files with 45 additions and 0 deletions

View File

@ -71,6 +71,38 @@ static AioContext *block_job_get_aio_context(BlockJob *job)
blk_get_aio_context(job->blk);
}
static void block_job_attached_aio_context(AioContext *new_context,
void *opaque)
{
BlockJob *job = opaque;
if (job->driver->attached_aio_context) {
job->driver->attached_aio_context(job, new_context);
}
block_job_resume(job);
}
static void block_job_detach_aio_context(void *opaque)
{
BlockJob *job = opaque;
/* In case the job terminates during aio_poll()... */
block_job_ref(job);
block_job_pause(job);
if (!job->paused) {
/* If job is !job->busy this kicks it into the next pause point. */
block_job_enter(job);
}
while (!job->paused && !job->completed) {
aio_poll(block_job_get_aio_context(job), true);
}
block_job_unref(job);
}
void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
int64_t speed, BlockCompletionFunc *cb,
void *opaque, Error **errp)
@ -103,6 +135,9 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
QLIST_INSERT_HEAD(&block_jobs, job, job_list);
blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
block_job_detach_aio_context, job);
/* Only set speed when necessary to avoid NotSupported error */
if (speed != 0) {
Error *local_err = NULL;
@ -128,6 +163,9 @@ void block_job_unref(BlockJob *job)
BlockDriverState *bs = blk_bs(job->blk);
bs->job = NULL;
bdrv_op_unblock_all(bs, job->blocker);
blk_remove_aio_context_notifier(job->blk,
block_job_attached_aio_context,
block_job_detach_aio_context, job);
blk_unref(job->blk);
error_free(job->blocker);
g_free(job->id);

View File

@ -84,6 +84,13 @@ typedef struct BlockJobDriver {
* should be restarted from this callback.
*/
void coroutine_fn (*resume)(BlockJob *job);
/*
* If the callback is not NULL, it will be invoked before the job is
* resumed in a new AioContext. This is the place to move any resources
* besides job->blk to the new AioContext.
*/
void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
} BlockJobDriver;
/**