linux-kernel - Re: [PATCH v4 3/5] bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap

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Date:   Tue, 28 Jan 2020 12:44:50 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Naresh Kamboju <naresh.kamboju@...aro.org>
Cc:     Sasha Levin <sashal@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>, dm-devel@...hat.com,
        Shaohua Li <shli@...nel.org>, linux-raid@...r.kernel.org,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        linux-input@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Yury Norov <ynorov@...iumnetworks.com>,
        open list <linux-kernel@...r.kernel.org>,
        mika.westerberg@...ux.intel.com, Joe Perches <joe@...ches.com>,
        linux- stable <stable@...r.kernel.org>,
        lkft-triage@...ts.linaro.org
Subject: Re: [PATCH v4 3/5] bitmap: Add bitmap_alloc(), bitmap_zalloc() and
 bitmap_free()

On Tue, Jan 28, 2020 at 05:08:27PM +0530, Naresh Kamboju wrote:
> On Sun, 1 Jul 2018 at 01:49, Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> >
> > A lot of code become ugly because of open coding allocations for bitmaps.
> >
> > Introduce three helpers to allow users be more clear of intention
> > and keep their code neat.
> >
> > Note, due to multiple circular dependencies we may not provide
> > the helpers as inliners. For now we keep them exported and, perhaps,
> > at some point in the future we will sort out header inclusion and
> > inheritance.
> >
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > ---
> >  include/linux/bitmap.h |  8 ++++++++
> >  lib/bitmap.c           | 19 +++++++++++++++++++
> >  2 files changed, 27 insertions(+)
> >
> > diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> > index 1ee46f492267..acf5e8df3504 100644
> > --- a/include/linux/bitmap.h
> > +++ b/include/linux/bitmap.h
> > @@ -104,6 +104,14 @@
> >   * contain all bit positions from 0 to 'bits' - 1.
> >   */
> >
> > +/*
> > + * Allocation and deallocation of bitmap.
> > + * Provided in lib/bitmap.c to avoid circular dependency.
> > + */
> > +extern unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
> > +extern unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
> > +extern void bitmap_free(const unsigned long *bitmap);
> > +
> >  /*
> >   * lib/bitmap.c provides these functions:
> >   */
> > diff --git a/lib/bitmap.c b/lib/bitmap.c
> > index 33e95cd359a2..09acf2fd6a35 100644
> > --- a/lib/bitmap.c
> > +++ b/lib/bitmap.c
> > @@ -13,6 +13,7 @@
> >  #include <linux/bitops.h>
> >  #include <linux/bug.h>
> >  #include <linux/kernel.h>
> > +#include <linux/slab.h>
> >  #include <linux/string.h>
> >  #include <linux/uaccess.h>
> >
> > @@ -1125,6 +1126,24 @@ void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int n
> >  EXPORT_SYMBOL(bitmap_copy_le);
> >  #endif
> >
> > +unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
> > +{
> > +       return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long), flags);
> > +}
> > +EXPORT_SYMBOL(bitmap_alloc);
> > +
> > +unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
> > +{
> > +       return bitmap_alloc(nbits, flags | __GFP_ZERO);
> > +}
> > +EXPORT_SYMBOL(bitmap_zalloc);
> > +
> > +void bitmap_free(const unsigned long *bitmap)
> > +{
> > +       kfree(bitmap);
> > +}
> > +EXPORT_SYMBOL(bitmap_free);
> > +
> >  #if BITS_PER_LONG == 64
> >  /**
> >   * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
> 
> stable-rc 4.14 build failed due to these build error,

Yeah, sorry, I noticed this right before I had to leave for a few hours.
I'll go fix this up now...

greg k-h