xen/scsiback: add error handling for xenbus_printf

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>

1 files changed, 13 insertions, 3 deletions

diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index 7bc88fd43cfc..e2f3e8b0fba9 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -1012,6 +1012,7 @@ static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 {
         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 vscsibk_info *info, const char *state,
                         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(struct vscsibk_info *info, int op,
         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(struct vscsibk_info *info, int op,
         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;
         }