Re: [PATCH v2 03/14] sysctl: Add ctl_table_size to ctl_table_header

Joel Granados <[email protected]> Tue, 1 Aug 2023 12:03:15 +0200

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Message-ID	<20230801100315.ymcahsxu6qpw7kct@localhost>

On Mon, Jul 31, 2023 at 09:07:06PM +0200, Simon Horman wrote:
> On Mon, Jul 31, 2023 at 08:30:34PM +0200, Simon Horman wrote:
> > On Mon, Jul 31, 2023 at 09:17:17AM +0200, Joel Granados wrote:
> > > The new ctl_table_size element will hold the size of the ctl_table
> > > arrays contained in the ctl_table_header. This value should eventually
> > > be passed by the callers to the sysctl register infrastructure. And
> > > while this commit introduces the variable, it does not set nor use it
> > > because that requires case by case considerations for each caller.
> > > 
> > > It provides two important things: (1) A place to put the
> > > result of the ctl_table array calculation when it gets introduced for
> > > each caller. And (2) the size that will be used as the additional
> > > stopping criteria in the list_for_each_table_entry macro (to be added
> > > when all the callers are migrated)
> > > 
> > > Signed-off-by: Joel Granados <[email protected]>
> > > ---
> > >  include/linux/sysctl.h | 14 ++++++++++++--
> > >  1 file changed, 12 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> > > index 59d451f455bf..33252ad58ebe 100644
> > > --- a/include/linux/sysctl.h
> > > +++ b/include/linux/sysctl.h
> > > @@ -159,12 +159,22 @@ struct ctl_node {
> > >  	struct ctl_table_header *header;
> > >  };
> > >  
> > > -/* struct ctl_table_header is used to maintain dynamic lists of
> > > -   struct ctl_table trees. */
> > > +/**
> > > + * struct ctl_table_header - maintains dynamic lists of struct ctl_table trees
> > > + * @ctl_table: pointer to the first element in ctl_table array
> > > + * @ctl_table_size: number of elements pointed by @ctl_table
> > > + * @used: The entry will never be touched when equal to 0.
> > > + * @count: Upped every time something is added to @inodes and downed every time
> > > + *         something is removed from inodes
> > > + * @nreg: When nreg drops to 0 the ctl_table_header will be unregistered.
> > > + * @rcu: Delays the freeing of the inode. Introduced with "unfuck proc_sysctl ->d_compare()"
> > > + *
> > > + */
> > 
> > Hi Joel,
> > 
> > Please consider also adding kernel doc entries for the other fields of
> > struct ctl_table_header. According to ./scripts/kernel-doc -none
> > they are:
> > 
> >   unregistering
> >   ctl_table_arg
> >   root
> >   set
> >   parent
> >   node
> >   inodes
> 
> Sorry, I now realise that I made the same comment on v1.
> And I didn't see your response to that until after I wrote the above.
np. I'll hold off adding this to the set until I get feedback from my
proposal. I do this as I'm unsure about the contents of the docs.


> 
> > 
> > 
> > >  struct ctl_table_header {
> > >  	union {
> > >  		struct {
> > >  			struct ctl_table *ctl_table;
> > > +			int ctl_table_size;
> > >  			int used;
> > >  			int count;
> > >  			int nreg;
> > > -- 
> > > 2.30.2
> > > 

-- 

Joel Granados

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