Cc'ing people based on output of "scripts/get_maintainer.pl -f include/block/aio-wait.h".
Dietmar Maurer <diet...@proxmox.com> writes: > Hi all, > > I have a question about AIO_WAIT_WHILE. The docs inside the code say: > > * The caller's thread must be the IOThread that owns @ctx or the main loop > * thread (with @ctx acquired exactly once). > > I wonder if that "with @ctx acquired exactly once" is always required? > > I have done a quick test (see code below) and this reveals that the condition > is not > always met. > > Or is my test wrong (or the docs)? > > ---debug helper--- > diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h > index afeeb18f95..cf78dca9f9 100644 > --- a/include/block/aio-wait.h > +++ b/include/block/aio-wait.h > @@ -82,6 +82,8 @@ extern AioWait global_aio_wait; > atomic_inc(&wait_->num_waiters); \ > if (ctx_ && in_aio_context_home_thread(ctx_)) { \ > while ((cond)) { \ > + printf("AIO_WAIT_WHILE %p %d\n", ctx, ctx_->lock_count); \ > + assert(ctx_->lock_count == 1); \ > aio_poll(ctx_, true); \ > waited_ = true; \ > } \ > diff --git a/include/block/aio.h b/include/block/aio.h > index cb1989105a..51ef20e2f0 100644 > --- a/include/block/aio.h > +++ b/include/block/aio.h > @@ -125,6 +125,7 @@ struct AioContext { > > /* Used by AioContext users to protect from multi-threaded access. */ > QemuRecMutex lock; > + int lock_count; > > /* The list of registered AIO handlers. Protected by ctx->list_lock. */ > AioHandlerList aio_handlers; > diff --git a/util/async.c b/util/async.c > index b94518b948..9804c6c64f 100644 > --- a/util/async.c > +++ b/util/async.c > @@ -594,9 +594,11 @@ void aio_context_unref(AioContext *ctx) > void aio_context_acquire(AioContext *ctx) > { > qemu_rec_mutex_lock(&ctx->lock); > + ctx->lock_count++; > } > > void aio_context_release(AioContext *ctx) > { > + ctx->lock_count--; > qemu_rec_mutex_unlock(&ctx->lock); > }