[PATCH v2 1/2] part: Add a function to find ESP partition

[Mayuresh Chitale]

On Tue, Jan 16, 2024 at 7:15 PM Heinrich Schuchardt <
heinrich.schuchardt at canonical.com> wrote:

> On 16.01.24 13:36, Mayuresh Chitale wrote:
> > If a disk has an EFI system partition (ESP) then it can be used to
> > locate the boot files. Add a function to find the ESP.
> >
> > Signed-off-by: Mayuresh Chitale <mchitale at ventanamicro.com>
> > Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> > ---
> >   disk/part.c    | 16 ++++++++++++++++
> >   include/part.h | 11 +++++++++++
> >   2 files changed, 27 insertions(+)
> >
> > diff --git a/disk/part.c b/disk/part.c
> > index 36b88205eca..6b1fbc18637 100644
> > --- a/disk/part.c
> > +++ b/disk/part.c
> > @@ -848,3 +848,19 @@ int part_get_bootable(struct blk_desc *desc)
> >
> >       return 0;
> >   }
> > +
> > +int part_get_esp(struct blk_desc *desc)
> > +{
> > +     struct disk_partition info;
> > +     int p;
> > +
> > +     for (p = 1; p <= MAX_SEARCH_PARTITIONS; p++) {
> > +             int ret;
> > +
> > +             ret = part_get_info(desc, p, &info);
> > +             if (!ret && (info.bootable & PART_EFI_SYSTEM_PARTITION))
> > +                     return p;
> > +     }
> > +
> > +     return 0;
> > +}
> > diff --git a/include/part.h b/include/part.h
> > index db34bc6bb7d..30e049c8f19 100644
> > --- a/include/part.h
> > +++ b/include/part.h
> > @@ -690,6 +690,14 @@ int part_get_type_by_name(const char *name);
> >    */
> >   int part_get_bootable(struct blk_desc *desc);
> >
> > +/**
> > + * part_get_esp() - Find the EFI system partition
> > + *
> > + * @desc: Block-device descriptor
> > + * @Return the EFI system partition, or 0 if there is none
>
> We want to be able to add the include to our API documentation. This
> requires adhering to the Sphinx documentation style.
>
> %s/@Return the/Return:/
>
> Ok.

> Cf.
>
> https://www.kernel.org/doc/html/v6.7/doc-guide/kernel-doc.html#function-documentation
>
> Best regards
>
> Heinrich
>
> > + */
> > +int part_get_esp(struct blk_desc *desc);
> > +
> >   #else
> >   static inline int part_driver_get_count(void)
> >   { return 0; }
> > @@ -700,6 +708,9 @@ static inline struct part_driver
> *part_driver_get_first(void)
> >   static inline bool part_get_bootable(struct blk_desc *desc)
> >   { return false; }
> >
> > +static inline bool part_get_esp(struct blk_desc *desc)
> > +{ return false; }
> > +
> >   #endif /* CONFIG_PARTITIONS */
> >
> >   #endif /* _PART_H */
>
>