Message-ID: <cae0b982-99fb-e808-0ff8-2f8d175b2d6d@oracle.com>
Date:   Mon, 6 Dec 2021 08:31:33 -0500
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Subject: Re: [PATCH] xen-blkfront: Use the bitmap API when applicable
Content-Language: en-US
To:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Joe Perches <joe@perches.com>, Juergen Gross <jgross@suse.com>,
        sstabellini@kernel.org, roger.pau@citrix.com, axboe@kernel.dk
Cc:     xen-devel@lists.xenproject.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
References: <1c73cf8eaff02ea19439ec676c063e592d273cfe.1638392965.git.christophe.jaillet@wanadoo.fr>
 <c529a221-f444-ad26-11ff-f693401c9429@suse.com>
 <d8f87c17-75d1-2e6b-65e1-23adc75bb515@wanadoo.fr>
 <6fcddba84070c021eb92aa9a5ff15fb2a47e9acb.camel@perches.com>
 <3d71577f-dabe-6e1a-4b03-2a44f304b702@wanadoo.fr>
 <863f2cddacac590d581cda09d548ee0a652df8a1.camel@perches.com>
 <1e9291c6-48bb-88e5-37dc-f604cfa4c4db@wanadoo.fr>
 <a6dd44e2-6ea6-d085-0131-1e9bac49461a@oracle.com>
 <f9a5bc6c-347b-8243-2784-04199ef879c2@wanadoo.fr>
From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
In-Reply-To: <f9a5bc6c-347b-8243-2784-04199ef879c2@wanadoo.fr>
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On 12/4/21 1:57 AM, Christophe JAILLET wrote:
>
> So, maybe adding an "official" 'bitmap_size()' (which is already existing and duplicated in a few places) would ease things.
>
> It would replace the 'nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;' and hide the implementation details of the bitmap API.
>
> Something like:
> static __always_inline size_t bitmap_size(unsigned long nr_bits)
> {
>     return BITS_TO_LONGS(nr_bits) * sizeof(long);
> }
>

Yes, I think this would be a useful helper. Should be sizeof(unsigned long) though to keep things consistent.


-boris