4.17-stable review patch. If anyone has any objections, please let me know.
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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; }