enum {
IO_CHECK_CQ_OVERFLOW_BIT,
+ IO_CHECK_CQ_DROPPED_BIT,
};
/*
* on the floor.
*/
io_account_cq_overflow(ctx);
+ set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
return false;
}
if (list_empty(&ctx->cq_overflow_list)) {
{
unsigned int nr_events = 0;
int ret = 0;
+ unsigned long check_cq;
/*
* Don't enter poll loop if we already have events pending.
* If we do, we can potentially be spinning for commands that
* already triggered a CQE (eg in error).
*/
- if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
+ check_cq = READ_ONCE(ctx->check_cq);
+ if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
__io_cqring_overflow_flush(ctx, false);
if (io_cqring_events(ctx))
return 0;
+
+ /*
+ * Similarly do not spin if we have not informed the user of any
+ * dropped CQE.
+ */
+ if (unlikely(check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)))
+ return -EBADR;
+
do {
/*
* If a submit got punted to a workqueue, we can have the
ktime_t timeout)
{
int ret;
+ unsigned long check_cq;
/* make sure we run task_work before checking for signals */
ret = io_run_task_work_sig();
if (ret || io_should_wake(iowq))
return ret;
+ check_cq = READ_ONCE(ctx->check_cq);
/* let the caller flush overflows, retry */
- if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
+ if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
return 1;
-
+ if (unlikely(check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)))
+ return -EBADR;
if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS))
return -ETIME;
return 1;
}
}
- if (!ret)
+ if (!ret) {
ret = ret2;
+ /*
+ * EBADR indicates that one or more CQE were dropped.
+ * Once the user has been informed we can clear the bit
+ * as they are obviously ok with those drops.
+ */
+ if (unlikely(ret2 == -EBADR))
+ clear_bit(IO_CHECK_CQ_DROPPED_BIT,
+ &ctx->check_cq);
+ }
}
out: