LinuxLists.cc - [PATCH] xen/scsiback: add error handling for xenbus

2018-06-12 04:08:23

Subject: [PATCH] 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 <[email protected]>
---
drivers/xen/xen-scsiback.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index 7bc88fd..13ab54c 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -1027,8 +1027,9 @@ 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,
- "%d", XenbusStateClosed);
+ if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
+ "%d", XenbusStateClosed))
+ pr_err("xenbus_printf error %s\n", state);
}
}

@@ -1067,8 +1068,9 @@ 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,
- "%d", XenbusStateClosed);
+ if (xenbus_printf(XBT_NIL, dev->nodename, state,
+ "%d", XenbusStateClosed))
+ pr_err("xenbus_printf error %s\n", state);
return;
}
strlcpy(phy, val, VSCSI_NAMELEN);
@@ -1079,8 +1081,9 @@ 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,
- "%d", XenbusStateClosed);
+ if (xenbus_printf(XBT_NIL, dev->nodename, state,
+ "%d", XenbusStateClosed))
+ pr_err("xenbus_printf error %s\n", state);
return;
}

--
2.7.4

2018-06-15 17:07:04

by Zhouyang Jia

[permalink] [raw]

Subject: [PATCH v2] 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 <[email protected]>
---
v1->v2:
- Use xenbus_dev_error to report errors.
---
drivers/xen/xen-scsiback.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index 7bc88fd..cec2133 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -1027,8 +1027,10 @@ 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,
- "%d", XenbusStateClosed);
+ if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
+ "%d", XenbusStateClosed))
+ xenbus_dev_error(info->dev, err,
+ "%s: writing %s", __func__, state);
}
}

@@ -1067,8 +1069,10 @@ 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,
- "%d", XenbusStateClosed);
+ if (xenbus_printf(XBT_NIL, dev->nodename, state,
+ "%d", XenbusStateClosed))
+ xenbus_dev_error(info->dev, err,
+ "%s: writing %s", __func__, state);
return;
}
strlcpy(phy, val, VSCSI_NAMELEN);
@@ -1079,8 +1083,10 @@ 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,
- "%d", XenbusStateClosed);
+ if (xenbus_printf(XBT_NIL, dev->nodename, state,
+ "%d", XenbusStateClosed))
+ xenbus_dev_error(info->dev, err,
+ "%s: writing %s", __func__, state);
return;
}

--
2.7.4

2018-06-15 19:24:22

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH v2] xen/scsiback: add error handling for xenbus_printf

Hi,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on xen-tip/linux-next]
[also build test ERROR on v4.17 next-20180615]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/linux-kernel-owner-vger-kernel-org/xen-scsiback-add-error-handling-for-xenbus_printf/20180616-011349
base: https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git linux-next
config: i386-randconfig-x009-201823 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386

All errors (new ones prefixed by >>):

drivers//xen/xen-scsiback.c: In function 'scsiback_do_add_lun':
>> drivers//xen/xen-scsiback.c:1032:32: error: 'err' undeclared (first use in this function)
xenbus_dev_error(info->dev, err,
^~~
drivers//xen/xen-scsiback.c:1032:32: note: each undeclared identifier is reported only once for each function it appears in

vim +/err +1032 drivers//xen/xen-scsiback.c

1009
1010 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1011 char *phy, struct ids_tuple *vir, int try)
1012 {
1013 struct v2p_entry *entry;
1014 unsigned long flags;
1015
1016 if (try) {
1017 spin_lock_irqsave(&info->v2p_lock, flags);
1018 entry = scsiback_chk_translation_entry(info, vir);
1019 spin_unlock_irqrestore(&info->v2p_lock, flags);
1020 if (entry)
1021 return;
1022 }
1023 if (!scsiback_add_translation_entry(info, phy, vir)) {
1024 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1025 "%d", XenbusStateInitialised)) {
1026 pr_err("xenbus_printf error %s\n", state);
1027 scsiback_del_translation_entry(info, vir);
1028 }
1029 } else if (!try) {
1030 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1031 "%d", XenbusStateClosed))
> 1032 xenbus_dev_error(info->dev, err,
1033 "%s: writing %s", __func__, state);
1034 }
1035 }
1036

---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation

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2018-06-16 00:15:48

by Zhouyang Jia

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Subject: [PATCH v3] 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 <[email protected]>
---
v1->v2:
- Use xenbus_dev_error to report errors.
v2->v3:
- Fix compilation errors.
---
drivers/xen/xen-scsiback.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index 7bc88fd..e2f3e8b 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;
}

--
2.7.4

2018-06-19 12:54:16

by Juergen Gross

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Subject: Re: [PATCH v3] xen/scsiback: add error handling for xenbus_printf

On 16/06/18 02:14, 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]>

Reviewed-by: Juergen Gross <[email protected]>

Juergen

2018-06-19 13:04:12

by Juergen Gross

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