diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2018-04-10 15:51:52 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2018-06-18 15:03:25 +0200 |
| commit | 4d22bbf4ef72583eefdf44db6bf9fc7683fbc4c2 (patch) | |
| tree | 1cb73c38dd003a6294b9451fb333f570b8ec6ed0 | |
| parent | 57320ca961c2e8488e1884b4ebbcb929b6901dc6 (diff) | |
block: Allow AIO_WAIT_WHILE with NULL ctx
bdrv_drain_all() wants to have a single polling loop for draining the
in-flight requests of all nodes. This means that the AIO_WAIT_WHILE()
condition relies on activity in multiple AioContexts, which is polled
from the mainloop context. We must therefore call AIO_WAIT_WHILE() from
the mainloop thread and use the AioWait notification mechanism.
Just randomly picking the AioContext of any non-mainloop thread would
work, but instead of bothering to find such a context in the caller, we
can just as well accept NULL for ctx.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | include/block/aio-wait.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h index 783d3678dd..c85a62f798 100644 --- a/include/block/aio-wait.h +++ b/include/block/aio-wait.h @@ -57,7 +57,8 @@ typedef struct { /** * AIO_WAIT_WHILE: * @wait: the aio wait object - * @ctx: the aio context + * @ctx: the aio context, or NULL if multiple aio contexts (for which the + * caller does not hold a lock) are involved in the polling condition. * @cond: wait while this conditional expression is true * * Wait while a condition is true. Use this to implement synchronous @@ -75,7 +76,7 @@ typedef struct { bool waited_ = false; \ AioWait *wait_ = (wait); \ AioContext *ctx_ = (ctx); \ - if (in_aio_context_home_thread(ctx_)) { \ + if (ctx_ && in_aio_context_home_thread(ctx_)) { \ while ((cond)) { \ aio_poll(ctx_, true); \ waited_ = true; \ @@ -86,9 +87,13 @@ typedef struct { /* Increment wait_->num_waiters before evaluating cond. */ \ atomic_inc(&wait_->num_waiters); \ while ((cond)) { \ - aio_context_release(ctx_); \ + if (ctx_) { \ + aio_context_release(ctx_); \ + } \ aio_poll(qemu_get_aio_context(), true); \ - aio_context_acquire(ctx_); \ + if (ctx_) { \ + aio_context_acquire(ctx_); \ + } \ waited_ = true; \ } \ atomic_dec(&wait_->num_waiters); \ |