linux-kernel - Re: [PATCH -next] scsi: aacraid: Use memdup

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Message-ID: <1a861285-8644-48d3-21c5-69c88e07db6f@huawei.com>
Date:   Sun, 26 Apr 2020 10:32:58 +0800
From:   Samuel Zou <zou_wei@...wei.com>
To:     "Martin K. Petersen" <martin.petersen@...cle.com>
CC:     <aacraid@...rosemi.com>, <jejb@...ux.ibm.com>,
        <linux-scsi@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH -next] scsi: aacraid: Use memdup_user() as a cleanup

Hi Martin,

Thanks for your review and reply.
You are right, it is not equivalent. I will keep the original goto 
cleanup. But the return value is changed to use of PTR_ERR 
(user_srbcmd), and assign it to rcode.
I will send the v2 soon later

On 2020/4/25 6:23, Martin K. Petersen wrote:
> 
> Zou,
> 
>> diff --git a/drivers/scsi/aacraid/commctrl.c b/drivers/scsi/aacraid/commctrl.c
>> index ffe41bc..1ce1620 100644
>> --- a/drivers/scsi/aacraid/commctrl.c
>> +++ b/drivers/scsi/aacraid/commctrl.c
>> @@ -513,17 +513,9 @@ static int aac_send_raw_srb(struct aac_dev* dev, void __user * arg)
>>   		goto cleanup;
>>   	}
>>   
>> -	user_srbcmd = kmalloc(fibsize, GFP_KERNEL);
>> -	if (!user_srbcmd) {
>> -		dprintk((KERN_DEBUG"aacraid: Could not make a copy of the srb\n"));
>> -		rcode = -ENOMEM;
>> -		goto cleanup;
>> -	}
>> -	if(copy_from_user(user_srbcmd, user_srb,fibsize)){
>> -		dprintk((KERN_DEBUG"aacraid: Could not copy srb from user\n"));
>> -		rcode = -EFAULT;
>> -		goto cleanup;
>> -	}
>> +	user_srbcmd = memdup_user(user_srb, fibsize);
>> +	if (IS_ERR(user_srbcmd))
>> +		return PTR_ERR(user_srbcmd);
>>   
>>   	flags = user_srbcmd->flags; /* from user in cpu order */
>>   	switch (flags & (SRB_DataIn | SRB_DataOut)) {
> 
> This is not equivalent, is it? The original code does a goto cleanup;
> whereas your patch returns on error.
>