Re: [PATCH] xen-blkfront: Use the bitmap API when applicable

[Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>]

Le 02/12/2021 à 07:12, Juergen Gross a écrit :
> On 01.12.21 22:10, Christophe JAILLET wrote:
> > Use 'bitmap_zalloc()' to simplify code, improve the semantic and avoid 
> > some
> > open-coded arithmetic in allocator arguments.
> >
> > Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
> > consistency.
> >
> > Use 'bitmap_copy()' to avoid an explicit 'memcpy()'
> >
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   drivers/block/xen-blkfront.c | 8 +++-----
> >   1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> > index 700c765a759a..fe4d69cf9469 100644
> > --- a/drivers/block/xen-blkfront.c
> > +++ b/drivers/block/xen-blkfront.c
> > @@ -442,16 +442,14 @@ static int xlbd_reserve_minors(unsigned int 
> > minor, unsigned int nr)
> >       if (end > nr_minors) {
> >           unsigned long *bitmap, *old;
> > -        bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
> > -                 GFP_KERNEL);
> > +        bitmap = bitmap_zalloc(end, GFP_KERNEL);
> >           if (bitmap == NULL)
> >               return -ENOMEM;
> >           spin_lock(&minor_lock);
> >           if (end > nr_minors) {
> >               old = minors;
> > -            memcpy(bitmap, minors,
> > -                   BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
> > +            bitmap_copy(bitmap, minors, nr_minors);
> >               minors = bitmap;
> >               nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
> >           } else
> Shouldn't you use bitmap_free(old) some lines down?
Obvious.
I'll send a V2, Thx for the review.

CJ

> > @@ -2610,7 +2608,7 @@ static void __exit xlblk_exit(void)
> >       xenbus_unregister_driver(&blkfront_driver);
> >       unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
> > -    kfree(minors);
> > +    bitmap_free(minors);
> >   }
> >   module_exit(xlblk_exit);
>
> Juergen