Commit 87dffe86 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Boris Ostrovsky

xen/manage: don't complain about an empty value in control/sysrq node

When guest receives a sysrq request from the host it acknowledges it by
writing '\0' to control/sysrq xenstore node. This, however, make xenstore
watch fire again but xenbus_scanf() fails to parse empty value with "%c"
format string:

 sysrq: SysRq : Emergency Sync
 Emergency Sync complete
 xen:manage: Error -34 reading sysrq code in control/sysrq

Ignore -ERANGE the same way we already ignore -ENOENT, empty value in
control/sysrq is totally legal.
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: default avatarWei Liu <wei.liu2@citrix.com>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent 11da3a7f
...@@ -280,9 +280,11 @@ static void sysrq_handler(struct xenbus_watch *watch, const char *path, ...@@ -280,9 +280,11 @@ static void sysrq_handler(struct xenbus_watch *watch, const char *path,
/* /*
* The Xenstore watch fires directly after registering it and * The Xenstore watch fires directly after registering it and
* after a suspend/resume cycle. So ENOENT is no error but * after a suspend/resume cycle. So ENOENT is no error but
* might happen in those cases. * might happen in those cases. ERANGE is observed when we get
* an empty value (''), this happens when we acknowledge the
* request by writing '\0' below.
*/ */
if (err != -ENOENT) if (err != -ENOENT && err != -ERANGE)
pr_err("Error %d reading sysrq code in control/sysrq\n", pr_err("Error %d reading sysrq code in control/sysrq\n",
err); err);
xenbus_transaction_end(xbt, 1); xenbus_transaction_end(xbt, 1);
......
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