This reverts commit 6133b39f3c36623425a6ede9e89d93175fde15cd.
The commit checked conditions that would expose a bug, but there is no
real reason to forbid them apart from the bug, which we'll fix in a
minute.
In particular, reentering a coroutine during co_aio_sleep_ns() is fine;
the function is explicitly written to allow this.
aio_co_schedule() can indeed conflict with direct coroutine invocations,
but this is exactky what we want to fix, so remove that check again,
too.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
include/qemu/coroutine_int.h | 13 +++----------
util/async.c | 13 -------------
util/qemu-coroutine-sleep.c | 12 ------------
util/qemu-coroutine.c | 14 --------------
4 files changed, 3 insertions(+), 49 deletions(-)
diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h
index 59e8406398..cb98892bba 100644
--- a/include/qemu/coroutine_int.h
+++ b/include/qemu/coroutine_int.h
@@ -46,21 +46,14 @@ struct Coroutine {
size_t locks_held;
- /* Only used when the coroutine has yielded. */
- AioContext *ctx;
-
- /* Used to catch and abort on illegal co-routine entry.
- * Will contain the name of the function that had first
- * scheduled the coroutine. */
- const char *scheduled;
-
- QSIMPLEQ_ENTRY(Coroutine) co_queue_next;
-
/* Coroutines that should be woken up when we yield or terminate.
* Only used when the coroutine is running.
*/
QSIMPLEQ_HEAD(, Coroutine) co_queue_wakeup;
+ /* Only used when the coroutine has yielded. */
+ AioContext *ctx;
+ QSIMPLEQ_ENTRY(Coroutine) co_queue_next;
QSLIST_ENTRY(Coroutine) co_scheduled_next;
};
diff --git a/util/async.c b/util/async.c
index 4dd9d95a9e..0e1bd8780a 100644
--- a/util/async.c
+++ b/util/async.c
@@ -388,9 +388,6 @@ static void co_schedule_bh_cb(void *opaque)
QSLIST_REMOVE_HEAD(&straight, co_scheduled_next);
trace_aio_co_schedule_bh_cb(ctx, co);
aio_context_acquire(ctx);
-
- /* Protected by write barrier in qemu_aio_coroutine_enter */
- atomic_set(&co->scheduled, NULL);
qemu_coroutine_enter(co);
aio_context_release(ctx);
}
@@ -441,16 +438,6 @@ fail:
void aio_co_schedule(AioContext *ctx, Coroutine *co)
{
trace_aio_co_schedule(ctx, co);
- const char *scheduled = atomic_cmpxchg(&co->scheduled, NULL,
- __func__);
-
- if (scheduled) {
- fprintf(stderr,
- "%s: Co-routine was already scheduled in '%s'\n",
- __func__, scheduled);
- abort();
- }
-
QSLIST_INSERT_HEAD_ATOMIC(&ctx->scheduled_coroutines,
co, co_scheduled_next);
qemu_bh_schedule(ctx->co_schedule_bh);
diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c
index 254349cdbb..9c5655041b 100644
--- a/util/qemu-coroutine-sleep.c
+++ b/util/qemu-coroutine-sleep.c
@@ -13,7 +13,6 @@
#include "qemu/osdep.h"
#include "qemu/coroutine.h"
-#include "qemu/coroutine_int.h"
#include "qemu/timer.h"
#include "block/aio.h"
@@ -26,8 +25,6 @@ static void co_sleep_cb(void *opaque)
{
CoSleepCB *sleep_cb = opaque;
- /* Write of schedule protected by barrier write in aio_co_schedule */
- atomic_set(&sleep_cb->co->scheduled, NULL);
aio_co_wake(sleep_cb->co);
}
@@ -37,15 +34,6 @@ void coroutine_fn co_aio_sleep_ns(AioContext *ctx,
QEMUClockType type,
CoSleepCB sleep_cb = {
.co = qemu_coroutine_self(),
};
-
- const char *scheduled = atomic_cmpxchg(&sleep_cb.co->scheduled, NULL,
- __func__);
- if (scheduled) {
- fprintf(stderr,
- "%s: Co-routine was already scheduled in '%s'\n",
- __func__, scheduled);
- abort();
- }
sleep_cb.ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, &sleep_cb);
timer_mod(sleep_cb.ts, qemu_clock_get_ns(type) + ns);
qemu_coroutine_yield();
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
index 9eff7fd450..d6095c1d5a 100644
--- a/util/qemu-coroutine.c
+++ b/util/qemu-coroutine.c
@@ -107,22 +107,8 @@ void qemu_aio_coroutine_enter(AioContext *ctx, Coroutine
*co)
Coroutine *self = qemu_coroutine_self();
CoroutineAction ret;
- /* Cannot rely on the read barrier for co in aio_co_wake(), as there are
- * callers outside of aio_co_wake() */
- const char *scheduled = atomic_mb_read(&co->scheduled);
-
trace_qemu_aio_coroutine_enter(ctx, self, co, co->entry_arg);
- /* if the Coroutine has already been scheduled, entering it again will
- * cause us to enter it twice, potentially even after the coroutine has
- * been deleted */
- if (scheduled) {
- fprintf(stderr,
- "%s: Co-routine was already scheduled in '%s'\n",
- __func__, scheduled);
- abort();
- }
-
if (co->caller) {
fprintf(stderr, "Co-routine re-entered recursively\n");
abort();
--
2.13.6
