[PATCH 4.14 052/217] xen/scsiback: add error handling for xenbus_printf

Greg Kroah-Hartman
2018-08-23T08:20:28Z

From: Zhouyang Jia <jiazhouyang09@gmail.com>

[ Upstream commit 7c63ca24c878e0051c91904b72174029320ef4bd ]

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 <jiazhouyang09@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/xen/xen-scsiback.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -1012,6 +1012,7 @@ static void scsiback_do_add_lun(struct v
{
struct v2p_entry *entry;
unsigned long flags;
+ int err;

if (try) {
spin_lock_irqsave(&info->v2p_lock, flags);
@@ -1027,8 +1028,11 @@ static void scsiback_do_add_lun(struct v
scsiback_del_translation_entry(info, vir);
}
} else if (!try) {
- xenbus_printf(XBT_NIL, info->dev->nodename, state,
+ err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
"%d", XenbusStateClosed);
+ if (err)
+ xenbus_dev_error(info->dev, err,
+ "%s: writing %s", __func__, state);
}
}

@@ -1067,8 +1071,11 @@ static void scsiback_do_1lun_hotplug(str
snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
if (IS_ERR(val)) {
- xenbus_printf(XBT_NIL, dev->nodename, state,
+ err = xenbus_printf(XBT_NIL, dev->nodename, state,
"%d", XenbusStateClosed);
+ if (err)
+ xenbus_dev_error(info->dev, err,
+ "%s: writing %s", __func__, state);
return;
}
strlcpy(phy, val, VSCSI_NAMELEN);
@@ -1079,8 +1086,11 @@ static void scsiback_do_1lun_hotplug(str
err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
&vir.hst, &vir.chn, &vir.tgt, &vir.lun);
if (XENBUS_EXIST_ERR(err)) {
- xenbus_printf(XBT_NIL, dev->nodename, state,
+ err = xenbus_printf(XBT_NIL, dev->nodename, state,
"%d", XenbusStateClosed);
+ if (err)
+ xenbus_dev_error(info->dev, err,
+ "%s: writing %s", __func__, state);
return;
}