netdev - Re: [PATCH iwl-net v3] ice: Fix memory management in ice_ethtool

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Message-ID: <25d3cd3d-e3c6-d3ef-d15e-8db497b03849@intel.com>
Date: Mon, 10 Jul 2023 13:48:04 -0700
From: Tony Nguyen <anthony.l.nguyen@...el.com>
To: "Jagielski, Jedrzej" <jedrzej.jagielski@...el.com>,
	"intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>
CC: "netdev@...r.kernel.org" <netdev@...r.kernel.org>, mschmidt
	<mschmidt@...hat.com>, "Kitszel, Przemyslaw" <przemyslaw.kitszel@...el.com>
Subject: Re: [PATCH iwl-net v3] ice: Fix memory management in
 ice_ethtool_fdir.c

On 7/10/2023 5:53 AM, Jagielski, Jedrzej wrote:

...

>>> -	seg = devm_kzalloc(dev, sizeof(*seg), GFP_KERNEL);
>>> -	if (!seg)
>>> -		return -ENOMEM;
>>> -
>>> -	tun_seg = devm_kcalloc(dev, ICE_FD_HW_SEG_MAX, sizeof(*tun_seg),
>>> -			       GFP_KERNEL);
>>> -	if (!tun_seg) {
>>> -		devm_kfree(dev, seg);
>>> -		return -ENOMEM;
>>> +	seg = kzalloc(sizeof(*seg), GFP_KERNEL);
>>> +	tun_seg = kcalloc(ICE_FD_HW_SEG_MAX, sizeof(*tun_seg), GFP_KERNEL);
>>> +	if (!tun_seg || !seg) {
>>> +		ret = -ENOMEM;
>>> +		goto exit;
>>
>> IIRC individual checks and goto's are preferred over combining them.
> 
> For both cases there is the same behavior so it was done due to limit
> the line redundancy, but if you think it is better to split them up i
> can do this

Please go back to individual checks; I found the previous comment [1].

"Don't do combined error checking, add appropriate labels for each case."

Also, as you're changing the allocation to not use the managed 
allocation, you're going to need to find the related (non-error) free 
and change those to be "regular" kfree as well.

Thanks,
Tony

[1] https://lore.kernel.org/netdev/20221115210239.3a1c05ba@kernel.org/