Hi, Sorry, I can't find which xenbus_device to print. So I inherit the existing style and use pr_err.
I add __func__ in v2. If it needs to be changed, please let me know. Thanks for your kind reply. Best, Zhouyang 2018-06-15 5:57 GMT+08:00 Boris Ostrovsky <[email protected]>: > On 06/11/2018 11:44 PM, Zhouyang Jia wrote: > > When xenbus_printf fails, the lack of error-handling code may > > cause unexpected results. > > > > This patch adds error-handling code after calling xenbus_printf. > > > > Signed-off-by: Zhouyang Jia <[email protected]> > > --- > > drivers/xen/manage.c | 17 ++++++++++++++--- > > 1 file changed, 14 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c > > index 8835065..159694d 100644 > > --- a/drivers/xen/manage.c > > +++ b/drivers/xen/manage.c > > @@ -289,8 +289,15 @@ static void sysrq_handler(struct xenbus_watch > *watch, const char *path, > > return; > > } > > > > - if (sysrq_key != '\0') > > - xenbus_printf(xbt, "control", "sysrq", "%c", '\0'); > > + if (sysrq_key != '\0') { > > + err = xenbus_printf(xbt, "control", "sysrq", "%c", '\0'); > > + if (err) { > > + pr_err("Error %d writing sysrq code in > control/sysrq\n", > > + err); > > + xenbus_transaction_end(xbt, 1); > > + return; > > + } > > + } > > > > err = xenbus_transaction_end(xbt, 0); > > if (err == -EAGAIN) > > @@ -342,7 +349,11 @@ static int setup_shutdown_watcher(void) > > continue; > > snprintf(node, FEATURE_PATH_SIZE, "feature-%s", > > shutdown_handlers[idx].command); > > - xenbus_printf(XBT_NIL, "control", node, "%u", 1); > > + err = xenbus_printf(XBT_NIL, "control", node, "%u", 1); > > + if (err) { > > + pr_err("Error %d writing %s\n", err, node); > > > Adding __func__ will make it it easier trying to understand where the > error is coming from. And for consistency, I'd add it to the one above > as well. > > > -boris > >
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