From: "Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de>
To: <jejb@linux.ibm.com>, <martin.petersen@oracle.com>,
"Chris Leech" <cleech@redhat.com>, <qtxuning1999@sjtu.edu.cn>,
"Lee Duncan" <lduncan@suse.com>
Cc: "open-iscsi" <open-iscsi@googlegroups.com>,
<linux-kernel@vger.kernel.org>, <linux-scsi@vger.kernel.org>
Subject: Re: Antw: [EXT] Re: [PATCH] scsi scsi_transport_iscsi.c: fix misuse of %llu in scsi_transport_iscsi.c
Date: Tue, 12 Oct 2021 09:04:28 +0200 [thread overview]
Message-ID: <6165337C020000A1000446A6@gwsmtp.uni-regensburg.de> (raw)
In-Reply-To: <ae7a82c2-5b19-493a-8d61-cdccb00cf46c@oracle.com>
>>> Mike Christie <michael.christie@oracle.com> schrieb am 11.10.2021 um 17:29 in
Nachricht <ae7a82c2-5b19-493a-8d61-cdccb00cf46c@oracle.com>:
> On 10/11/21 1:35 AM, Ulrich Windl wrote:
>>>>> Joe Perches <joe@perches.com> schrieb am 09.10.2021 um 05:14 in Nachricht
>> <5daf69b365e23ceecee911c4d0f2f66a0b9ec95c.camel@perches.com>:
>>> On Sat, 2021-10-09 at 11:02 +0800, Guo Zhi wrote:
>>>> Pointers should be printed with %p or %px rather than
>>>> cast to (unsigned long long) and printed with %llu.
>>>> Change %llu to %p to print the pointer into sysfs.
>>> ][]
>>>> diff --git a/drivers/scsi/scsi_transport_iscsi.c
>>> b/drivers/scsi/scsi_transport_iscsi.c
>>> []
>>>> @@ -129,8 +129,8 @@ show_transport_handle(struct device *dev, struct
>>> device_attribute *attr,
>>>>
>>>>
>>>> if (!capable(CAP_SYS_ADMIN))
>>>> return -EACCES;
>>>> - return sysfs_emit(buf, "%llu\n",
>>>> - (unsigned long long)iscsi_handle(priv->iscsi_transport));
>>>> + return sysfs_emit(buf, "%p\n",
>>>> + iscsi_ptr(priv->iscsi_transport));
>>>
>>> iscsi_transport is a pointer isn't it?
>>>
>>> so why not just
>>>
>>> return sysfs_emit(buf, "%p\n", priv->iscsi_transport);
>>
>> Isn't the difference that %p outputs hex, while %u outputs decimal?
>>
>
> Yeah, I think this patch will break userspace, because it doesn't know it's
> a pointer. It could be doing:
>
> sscanf(str, "%llu", &val);
>
> The value is just later passed back to the kernel to look up a driver in
> iscsi_if_transport_lookup:
>
> list_for_each_entry(priv, &iscsi_transports, list) {
> if (tt == priv->iscsi_transport) {
>
> so we could just replace priv->transport with an int and use an ida to assign
> the value.
I'm not in the details, but if that value is used as an ID, shouldn't it have been something like "ID%llu" right from the start?
If so it would be rather easy to use "ID%p" instead (if the syntax of the ID is left unspecified). At least nobody would treat it as a number.
Regards,
Ulrich
>
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> f46c%40oracle.com.
next prev parent reply other threads:[~2021-10-12 7:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 3:02 [PATCH] scsi scsi_transport_iscsi.c: fix misuse of %llu in scsi_transport_iscsi.c Guo Zhi
2021-10-09 3:14 ` Joe Perches
2021-10-09 4:35 ` Guo Zhi
2021-10-11 6:35 ` Antw: [EXT] " Ulrich Windl
2021-10-11 15:29 ` Mike Christie
2021-10-12 7:04 ` Ulrich Windl [this message]
2021-10-15 7:36 ` Guo Zhi
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