Re: [PATCH] nfsd: make destory function more elegant

From: Chuck Lever III
Date: Fri Jun 03 2022 - 10:03:07 EST




> On Jun 3, 2022, at 9:50 AM, Dongliang Mu <mudongliangabcd@xxxxxxxxx> wrote:
>
> On Thu, Jun 2, 2022 at 10:30 PM Chuck Lever III <chuck.lever@xxxxxxxxxx> wrote:
>>
>>
>>
>>> On Jun 2, 2022, at 1:56 AM, Dongliang Mu <dzm91@xxxxxxxxxxx> wrote:
>>>
>>> From: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
>>>
>>> In init_nfsd, the undo operation of create_proc_exports_entry is:
>>>
>>> remove_proc_entry("fs/nfs/exports", NULL);
>>> remove_proc_entry("fs/nfs", NULL);
>>>
>>> This may lead to maintaince issue. Declare the undo function
>>
>> "maintenance"
>
> Sorry for the typo.
>
>>
>>
>>> destroy_proc_exports_entry based on CONFIG_PROC_FS
>>
>> IIUC, the issue is that if CONFIG_PROC_FS is not set,
>> fs/nfsd/nfsctl.c fails to compile?
>
> The answer is no. There is no bug in the code.
>
> At first, I thought this might cause the miscompilation or bug. But
> actually the code is fine.
>
> Because remove_proc_entry is defined as an empty function if
> CONFIG_PROC_FS is not set,

Code inspection does suggest there could be a problem,
but I'm glad there isn't one. I can drop this one.


>>> Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
>>> ---
>>> fs/nfsd/nfsctl.c | 16 ++++++++++++----
>>> 1 file changed, 12 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
>>> index 0621c2faf242..83b34ccbef5a 100644
>>> --- a/fs/nfsd/nfsctl.c
>>> +++ b/fs/nfsd/nfsctl.c
>>> @@ -1450,11 +1450,21 @@ static int create_proc_exports_entry(void)
>>> }
>>> return 0;
>>> }
>>> +
>>> +static void destroy_proc_exports_entry(void)
>>> +{
>>> + remove_proc_entry("fs/nfs/exports", NULL);
>>> + remove_proc_entry("fs/nfs", NULL);
>>> +}
>>> #else /* CONFIG_PROC_FS */
>>> static int create_proc_exports_entry(void)
>>> {
>>> return 0;
>>> }
>>> +
>>> +static void destroy_proc_exports_entry(void)
>>> +{
>>> +}
>>> #endif
>>>
>>> unsigned int nfsd_net_id;
>>> @@ -1555,8 +1565,7 @@ static int __init init_nfsd(void)
>>> out_free_subsys:
>>> unregister_pernet_subsys(&nfsd_net_ops);
>>> out_free_exports:
>>> - remove_proc_entry("fs/nfs/exports", NULL);
>>> - remove_proc_entry("fs/nfs", NULL);
>>> + destroy_proc_exports_entry();
>>> out_free_lockd:
>>> nfsd_lockd_shutdown();
>>> nfsd_drc_slab_free();
>>> @@ -1576,8 +1585,7 @@ static void __exit exit_nfsd(void)
>>> unregister_cld_notifier();
>>> unregister_pernet_subsys(&nfsd_net_ops);
>>> nfsd_drc_slab_free();
>>> - remove_proc_entry("fs/nfs/exports", NULL);
>>> - remove_proc_entry("fs/nfs", NULL);
>>> + destroy_proc_exports_entry();
>>> nfsd_stat_shutdown();
>>> nfsd_lockd_shutdown();
>>> nfsd4_free_slabs();
>>> --
>>> 2.25.1
>>>
>>
>> --
>> Chuck Lever

--
Chuck Lever