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Subject: Re: [PATCH] wifi: ath10k: Fix resource leak in ath10k_pci_init()
To:     Jeff Johnson <quic_jjohnson@quicinc.com>, <kvalo@kernel.org>,
        <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <rmani@qti.qualcomm.com>
CC:     <ath10k@lists.infradead.org>, <linux-wireless@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20221108133858.53308-1-xiujianfeng@huawei.com>
 <4e81efea-23f1-e52c-b0b4-abf445ed5f15@quicinc.com>
From:   xiujianfeng <xiujianfeng@huawei.com>
Message-ID: <cd3194f8-3cad-ce12-602f-8651e99365ab@huawei.com>
Date:   Thu, 10 Nov 2022 09:54:05 +0800
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Hi,

在 2022/11/10 0:34, Jeff Johnson 写道:
> On 11/8/2022 5:38 AM, Xiu Jianfeng wrote:
>> When ath10k_ahb_init() fails, it does not unregister ath10k_pci_driver,
>> which will cause a resource leak issue, call pci_unregister_driver() in
>> the error path to fix this issue.
>>
>> Fixes: 0b523ced9a3c ("ath10k: add basic skeleton to support ahb")
>> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
>> ---
>>   drivers/net/wireless/ath/ath10k/pci.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath10k/pci.c 
>> b/drivers/net/wireless/ath/ath10k/pci.c
>> index e56c6a6b1379..22f8f8b20762 100644
>> --- a/drivers/net/wireless/ath/ath10k/pci.c
>> +++ b/drivers/net/wireless/ath/ath10k/pci.c
>> @@ -3800,8 +3800,10 @@ static int __init ath10k_pci_init(void)
>>                  ret);
>>       ret = ath10k_ahb_init();
>> -    if (ret)
>> +    if (ret) {
>>           printk(KERN_ERR "ahb init failed: %d\n", ret);
>> +        pci_unregister_driver(&ath10k_pci_driver);
>> +    }
>>       return ret;
>>   }
> 
> imo neither the existing code nor the modified code is correct.
> 
> the driver is attempting to register to support two different buses.
> 
> if either of these is successful then ath10k_pci_init() should return 0 
> so that hardware attached to the successful bus can be probed and 
> supported.
> 
> only if both of these are unsuccessful should ath10k_pci_init() return 
> an errno.
> 
> so I suggest
>      int ret1, ret2;
> 
>      ret1 = pci_register_driver(&ath10k_pci_driver);
>      if (ret1)
>          printk(KERN_ERR "failed to register ath10k pci driver: %d\n",
>                 ret1);
> 
>      ret2 = ath10k_ahb_init();
>      if (ret2)
>          printk(KERN_ERR "ahb init failed: %d\n", ret2);
> 
>      if (ret1 && ret2)
>          return ret1;
> 
>      /* registered to at least one bus */
>      return 0;
> }

Thanks, this is better. however, if pci_register_driver() returns 0
while ath10k_ahb_init() returns error, it's better to unregister the
first bus, here is my another proposal:

         int ret;

         ret = pci_register_driver(&ath10k_pci_driver);
         if (ret) {
                 printk(KERN_ERR "failed to register ath10k pci driver: 
%d\n",
                        ret);
                 return ret;
         }

         ret = ath10k_ahb_init();
         if (ret) {
                 printk(KERN_ERR "ahb init failed: %d\n", ret);
                 pci_unregister_driver(&ath10k_pci_driver);
                 return ret;
         }

         return 0;

If you agree, I will send v2 with this.

> 
> .