Re: [PATCH 1/2] sysctl: introduce new proc handler proc_dobool

[Thomas Huth]

On 18/08/2021 11.38, Thomas Huth wrote:
> On 03/08/2021 12.59, Thomas Huth wrote:
> > From: Jia He <hejianet@xxxxxxxxx>
> >
> > This is to let bool variable could be correctly displayed in
> > big/little endian sysctl procfs. sizeof(bool) is arch dependent,
> > proc_dobool should work in all arches.
> >
> > Suggested-by: Pan Xinhui <xinhui@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Jia He <hejianet@xxxxxxxxx>
> > [thuth: rebased the patch to the current kernel version]
> > Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
> > ---
> >   include/linux/sysctl.h |  2 ++
> >   kernel/sysctl.c        | 42 ++++++++++++++++++++++++++++++++++++++++++
> >   2 files changed, 44 insertions(+)
> >
> > diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> > index d99ca99837de..1fa2b69c6fc3 100644
> > --- a/include/linux/sysctl.h
> > +++ b/include/linux/sysctl.h
> > @@ -48,6 +48,8 @@ typedef int proc_handler(struct ctl_table *ctl, int 
> > write, void *buffer,
> >           size_t *lenp, loff_t *ppos);
> >   int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
> > +int proc_dobool(struct ctl_table *table, int write, void *buffer,
> > +        size_t *lenp, loff_t *ppos);
> >   int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
> >   int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
> >   int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, 
> > loff_t *);
> > diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> > index 272f4a272f8c..25e49b4d8049 100644
> > --- a/kernel/sysctl.c
> > +++ b/kernel/sysctl.c
> > @@ -536,6 +536,21 @@ static void proc_put_char(void **buf, size_t *size, 
> > char c)
> >       }
> >   }
> > +static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp,
> > +                int *valp,
> > +                int write, void *data)
> > +{
> > +    if (write) {
> > +        *(bool *)valp = *lvalp;
> > +    } else {
> > +        int val = *(bool *)valp;
> > +
> > +        *lvalp = (unsigned long)val;
> > +        *negp = false;
> > +    }
> > +    return 0;
> > +}
> > +
> >   static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
> >                    int *valp,
> >                    int write, void *data)
> > @@ -798,6 +813,26 @@ static int do_proc_douintvec(struct ctl_table *table, 
> > int write,
> >                      buffer, lenp, ppos, conv, data);
> >   }
> > +/**
> > + * proc_dobool - read/write a bool
> > + * @table: the sysctl table
> > + * @write: %TRUE if this is a write to the sysctl file
> > + * @buffer: the user buffer
> > + * @lenp: the size of the user buffer
> > + * @ppos: file position
> > + *
> > + * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
> > + * values from/to the user buffer, treated as an ASCII string.
> > + *
> > + * Returns 0 on success.
> > + */
> > +int proc_dobool(struct ctl_table *table, int write, void *buffer,
> > +        size_t *lenp, loff_t *ppos)
> > +{
> > +    return do_proc_dointvec(table, write, buffer, lenp, ppos,
> > +                do_proc_dobool_conv, NULL);
> > +}
> > +
> >   /**
> >    * proc_dointvec - read a vector of integers
> >    * @table: the sysctl table
> > @@ -1630,6 +1665,12 @@ int proc_dostring(struct ctl_table *table, int write,
> >       return -ENOSYS;
> >   }
> > +int proc_dobool(struct ctl_table *table, int write,
> > +        void *buffer, size_t *lenp, loff_t *ppos)
> > +{
> > +    return -ENOSYS;
> > +}
> > +
> >   int proc_dointvec(struct ctl_table *table, int write,
> >             void *buffer, size_t *lenp, loff_t *ppos)
> >   {
> > @@ -3425,6 +3466,7 @@ int __init sysctl_init(void)
> >    * No sense putting this after each symbol definition, twice,
> >    * exception granted :-)
> >    */
> > +EXPORT_SYMBOL(proc_dobool);
> >   EXPORT_SYMBOL(proc_dointvec);
> >   EXPORT_SYMBOL(proc_douintvec);
> >   EXPORT_SYMBOL(proc_dointvec_jiffies);
>
> Friendly ping!
>
> Luis, Kees, Iurii, could you please have a look and provide an Ack if this 
> looks ok to you?

Ping again!

Could anybody please provide an Ack?

Thanks,
 Thomas