On 3.02.25 9:27, Pavel Tikhomirov wrote:
On 2/3/25 14:45, Alexander Atanasov wrote:
On 3.02.25 8:01, Pavel Tikhomirov wrote:
@@ -166,7 +171,6 @@ static bool ploop_try_delay_enospc(struct
ploop_rq *prq, struct pio *pio)
bool delayed = true;
unsigned long flags;
- spin_lock_irqsave(&ploop->deferred_lock, flags);
if (unlikely(ploop->wants_suspend)) {
delayed = false;
goto unlock;
@@ -176,10 +180,11 @@ static bool ploop_try_delay_enospc(struct
ploop_rq *prq, struct pio *pio)
pr_err_once(PL_FMT("underlying disk is almost full"),
ploop_device_name(ploop));
+ spin_lock_irqsave(&ploop->deferred_lock, flags);
ploop->event_enospc = true;
- list_add_tail(&pio->list, &ploop->enospc_pios);
-unlock:
spin_unlock_irqrestore(&ploop->deferred_lock, flags);
+ llist_add((struct llist_node *)(&pio->list), &ploop->enospc_pios);
+unlock:
if (delayed)
mod_timer(&ploop->enospc_timer, jiffies +
PLOOP_ENOSPC_TIMEOUT);
Can you please explain why we need to take defered_lock around ploop-
>event_enospc setting after your patch? (It looks that this lock does
not do anything now.)
see static int ploop_get_event(...), without lock event can be missed
That is not an explanation. How exactly can it be missed?
spin_lock_irq(&ploop->deferred_lock);
if (ploop->event_enospc) { <- while emit
other cpu can set
ret = (DMEMIT("event_ENOSPC\n")) ? 1 : 0;
if (ret)
ploop->event_enospc = false; <- next cleaars
here -> second event lost
}
spin_unlock_irq(&ploop->deferred_lock);
--
Regards,
Alexander Atanasov
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