On Tue, Mar 21, 2017 at 06:48:10PM +0100, Paolo Bonzini wrote: > Streaming or any other block job hangs when performed on a block device > that has a non-default iothread. This happens because the AioContext > is acquired twice by block_job_defer_to_main_loop_bh and then released > only once by BDRV_POLL_WHILE. (Insert rants on recursive mutexes, which > > unfortunately are a temporary but necessary evil for iothreads at the > moment). > > Luckily, the reason for the double acquisition is simple; the function > acquires the AioContext for both the job iothread and the BDS iothread, > in case the BDS iothread was changed while the job was running. It > is therefore enough to skip the second acquisition when the two > AioContexts are one and the same. > > Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> > --- > blockjob.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/blockjob.c b/blockjob.c > index 69126af..2159df7 100644 > --- a/blockjob.c > +++ b/blockjob.c > @@ -755,12 +755,16 @@ static void block_job_defer_to_main_loop_bh(void > *opaque) > > /* Fetch BDS AioContext again, in case it has changed */ > aio_context = blk_get_aio_context(data->job->blk); > - aio_context_acquire(aio_context); > + if (aio_context != data->aio_context) { > + aio_context_acquire(aio_context); > + } > > data->job->deferred_to_main_loop = false; > data->fn(data->job, data->opaque); > > - aio_context_release(aio_context); > + if (aio_context != data->aio_context) { > + aio_context_release(aio_context); > + } > > aio_context_release(data->aio_context); > > -- > 1.8.3.1 > >
Deleted the blank line in the commit message, and: Thanks, Applied to my block branch: git://github.com/codyprime/qemu-kvm-jtc.git block -Jeff