Subject: Re: [PATCH -next 2/2] sata_fsl: fix warning in remove_proc_entry when
 rmmod sata_fsl
To:     Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        <axboe@kernel.dk>, <tj@kernel.org>, <linux-ide@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     <yebin10@huawei.com>, <yukuai3@huawei.com>,
        Hulk Robot <hulkci@huawei.com>
References: <20211119041128.2436889-1-libaokun1@huawei.com>
 <20211119041128.2436889-3-libaokun1@huawei.com>
 <aae68060-2941-36fd-0abb-e10fdc687111@opensource.wdc.com>
From:   "libaokun (A)" <libaokun1@huawei.com>
Message-ID: <9fa29aa2-0124-c61b-8334-084627c2f004@huawei.com>
Date:   Sat, 20 Nov 2021 10:22:24 +0800
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在 2021/11/20 6:18, Damien Le Moal 写道:
> On 11/19/21 13:11, Baokun Li wrote:
>> Trying to remove the fsl-sata module in the PPC64 GNU/Linux
>> leads to the following warning:
>>   ------------[ cut here ]------------
>>   remove_proc_entry: removing non-empty directory 'irq/69',
>>     leaking at least 'fsl-sata[ff0221000.sata]'
>>   WARNING: CPU: 3 PID: 1048 at fs/proc/generic.c:722
>>     .remove_proc_entry+0x20c/0x220
>>   IRQMASK: 0
>>   NIP [c00000000033826c] .remove_proc_entry+0x20c/0x220
>>   LR [c000000000338268] .remove_proc_entry+0x208/0x220
>>   Call Trace:
>>    .remove_proc_entry+0x208/0x220 (unreliable)
>>    .unregister_irq_proc+0x104/0x140
>>    .free_desc+0x44/0xb0
>>    .irq_free_descs+0x9c/0xf0
>>    .irq_dispose_mapping+0x64/0xa0
>>    .sata_fsl_remove+0x58/0xa0 [sata_fsl]
>>    .platform_drv_remove+0x40/0x90
>>    .device_release_driver_internal+0x160/0x2c0
>>    .driver_detach+0x64/0xd0
>>    .bus_remove_driver+0x70/0xf0
>>    .driver_unregister+0x38/0x80
>>    .platform_driver_unregister+0x14/0x30
>>    .fsl_sata_driver_exit+0x18/0xa20 [sata_fsl]
>>   ---[ end trace 0ea876d4076908f5 ]---
>>
>> The driver creates the mapping by calling irq_of_parse_and_map(),
>> so it also has to dispose the mapping. But the easy way out is to
>> simply use platform_get_irq() instead of irq_of_parse_map().
>>
>> In this case the mapping is not managed by the device but by
>> the of core, so the device has not to dispose the mapping.
>>
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: Baokun Li <libaokun1@huawei.com>
>> ---
>>   drivers/ata/sata_fsl.c | 4 +---
>>   1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
>> index 30759fd1c3a2..011daac4a14e 100644
>> --- a/drivers/ata/sata_fsl.c
>> +++ b/drivers/ata/sata_fsl.c
>> @@ -1493,7 +1493,7 @@ static int sata_fsl_probe(struct platform_device *ofdev)
>>   	host_priv->ssr_base = ssr_base;
>>   	host_priv->csr_base = csr_base;
>>   
>> -	irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
>> +	irq = platform_get_irq(ofdev, 0);
>>   	if (!irq) {
> Please see the kdoc comment for platform_get_irq() in
> drivers/base/platform.c. The error check must be "if (irq < 0)".
>
> Can you send a V2 with that fixed and tested ?
>
>>   		dev_err(&ofdev->dev, "invalid irq from platform\n");
>>   		goto error_exit_with_cleanup;
>> @@ -1570,8 +1570,6 @@ static int sata_fsl_remove(struct platform_device *ofdev)
>>   
>>   	ata_host_detach(host);
>>   
>> -	irq_dispose_mapping(host_priv->irq);
>> -
>>   	return 0;
>>   }
>>   
>>
>
I didn't notice the change in this return value, and the test didn't 
cover the error branch.

Thank you very much for your advice.

I'm about to send a patch v2 with the changes suggested by you.

-- With Best Regards, Baokun Li .