From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <amwang@redhat.com>
Subject: Re: [net-next PATCH v4 1/3] sysctl: refactor integer handling proc
 code
Date: Tue, 16 Feb 2010 21:09:51 +0800
Message-ID: <4B7A991F.3040601@redhat.com>
References: <1266271241-6293-1-git-send-email-opurdila@ixiacom.com> <1266271241-6293-2-git-send-email-opurdila@ixiacom.com> <4B7A5A23.3080309@redhat.com> <201002161341.56206.opurdila@ixiacom.com>
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Cc: David Miller <davem@davemloft.net>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	Linux Kernel Developers <linux-kernel@vger.kernel.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>
To: Octavian Purdila <opurdila@ixiacom.com>
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Octavian Purdila wrote:
> On Tuesday 16 February 2010 10:41:07 you wrote:
> 
>>> +static int proc_skip_wspace(char __user **buf, size_t *size)
>>> +{
>>> +     char c;
>>> +
>>> +     while (*size) {
>>> +             if (get_user(c, *buf))
>>> +                     return -EFAULT;
>>> +             if (!isspace(c))
>>> +                     break;
>>> +             (*size)--; (*buf)++;
>>> +     }
>>> +
>>> +     return 0;
>>> +}
>> In lib/string.c we have skip_spaces(), I think we can use it
>> here instead of inventing another one.
>>
> 
> I'm afraid we can't, skip_spaces does not accept userspace buffers.

Well, you need to use copy_from_user() before call it.