linux-kernel - Re: [PATCH v3 3/5] bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap

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Date:   Mon, 18 Jun 2018 15:01:43 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        agk@...hat.com, Mike Snitzer <snitzer@...hat.com>,
        device-mapper development <dm-devel@...hat.com>,
        shli@...nel.org, linux-raid@...r.kernel.org,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        ynorov@...iumnetworks.com, lkml <linux-kernel@...r.kernel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Joe Perches <joe@...ches.com>
Subject: Re: [PATCH v3 3/5] bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free()

On Mon, Jun 18, 2018 at 2:14 PM Andrew Morton <akpm@...ux-foundation.org> wrote:
>
> On Mon, 18 Jun 2018 16:10:01 +0300 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.
> >
> > ...
> >
> > +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);
> > +
>
> I suggest these functions are small and simple enough to justify
> inlining them.
>

We can't as we end up including bitmap.h (by the way of cpumask.h)
form slab.h, so we gen circular dependency. Maybe if we removed memcg
stuff from slab.h so we do not need to include workqueue.h...

-- 
Dmitry