3.18-stable review patch. If anyone has any objections, please let me know.
------------------ From: Juergen Gross <[email protected]> [ Upstream commit 4e93b6481c87ea5afde944a32b4908357ec58992 ] When registering for the Xenstore watch of the node control/sysrq the handler will be called at once. Don't issue an error message if the Xenstore node isn't there, as it will be created only when an event is being triggered. Signed-off-by: Juergen Gross <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/xen/manage.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -272,8 +272,16 @@ static void sysrq_handler(struct xenbus_ err = xenbus_transaction_start(&xbt); if (err) return; - if (xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key) < 0) { - pr_err("Unable to read sysrq code in control/sysrq\n"); + err = xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key); + if (err < 0) { + /* + * The Xenstore watch fires directly after registering it and + * after a suspend/resume cycle. So ENOENT is no error but + * might happen in those cases. + */ + if (err != -ENOENT) + pr_err("Error %d reading sysrq code in control/sysrq\n", + err); xenbus_transaction_end(xbt, 1); return; }
