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Commit cfb5946b authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

tty: hvc: hvc_poll() may sleep 



Introduce points where hvc_poll drops the lock, enables interrupts,
and reschedules.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent ec97eaad

drivers/tty/hvc/hvc_console.c

+14 −2
Original line number Diff line number Diff line
@@ -589,7 +589,7 @@ static u32 timeout = MIN_TIMEOUT; 
#define HVC_POLL_READ	0x00000001

#define HVC_POLL_WRITE	0x00000002



int hvc_poll(struct hvc_struct *hp)

static int __hvc_poll(struct hvc_struct *hp, bool may_sleep)

{

	struct tty_struct *tty;

	int i, n, count, poll_mask = 0;
@@ -611,6 +611,12 @@ int hvc_poll(struct hvc_struct *hp) 
		timeout = (written_total) ? 0 : MIN_TIMEOUT;

	}



	if (may_sleep) {

		spin_unlock_irqrestore(&hp->lock, flags);

		cond_resched();

		spin_lock_irqsave(&hp->lock, flags);

	}



	/* No tty attached, just skip */

	tty = tty_port_tty_get(&hp->port);

	if (tty == NULL)
@@ -698,6 +704,11 @@ int hvc_poll(struct hvc_struct *hp) 


	return poll_mask;

}



int hvc_poll(struct hvc_struct *hp)

{

	return __hvc_poll(hp, false);

}

EXPORT_SYMBOL_GPL(hvc_poll);



/**
@@ -736,7 +747,8 @@ static int khvcd(void *unused) 
		if (!cpus_are_in_xmon()) {

			mutex_lock(&hvc_structs_mutex);

			list_for_each_entry(hp, &hvc_structs, next) {

				poll_mask |= hvc_poll(hp);

				poll_mask |= __hvc_poll(hp, true);

				cond_resched();

			}

			mutex_unlock(&hvc_structs_mutex);

		} else