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From:   Paulo Alcantara <pc@cjr.nz>
To:     =?utf-8?Q?Aur=C3=A9lien?= Aptel <aurelien.aptel@gmail.com>
Cc:     smfrench@gmail.com, linux-cifs@vger.kernel.org
Subject: Re: [PATCH 1/5] cifs: fix potential deadlock in cache_refresh_path()
In-Reply-To: <CA+5B0FPp5ELawadvymYumQPSaCrCL15=2_KiCX2=91u6KBoVyw@mail.gmail.com>
References: <20230117000952.9965-1-pc@cjr.nz>
 <20230117000952.9965-2-pc@cjr.nz>
 <CA+5B0FPp5ELawadvymYumQPSaCrCL15=2_KiCX2=91u6KBoVyw@mail.gmail.com>
Date:   Tue, 17 Jan 2023 15:03:18 -0300
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Aur=C3=A9lien Aptel <aurelien.aptel@gmail.com> writes:

> On Tue, Jan 17, 2023 at 1:35 AM Paulo Alcantara <pc@cjr.nz> wrote:
>> -       down_write(&htable_rw_lock);
>> +       down_read(&htable_rw_lock);
>>
>>         ce =3D lookup_cache_entry(path);
>> -       if (!IS_ERR(ce)) {
>> -               if (!cache_entry_expired(ce)) {
>> -                       dump_ce(ce);
>> -                       up_write(&htable_rw_lock);
>> -                       return 0;
>> -               }
>> -       } else {
>> -               newent =3D true;
>> +       if (!IS_ERR(ce) && !cache_entry_expired(ce)) {
>> +               up_read(&htable_rw_lock);
>> +               return 0;
>>         }
>>
>> +       up_read(&htable_rw_lock);
>
> Please add a comment before the up_read() to say why you do it here
> and where is the dead lock.

Ok, thanks.  Will send v2 with your suggestions.