From: David Howells <dhowells@redhat.com>
To: Colin Ian King <colin.king@canonical.com>
Cc: dhowells@redhat.com, linux-afs@lists.infradead.org,
kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] afs: fix integer overflow when shifting 1 more than 32 places
Date: Wed, 11 Apr 2018 15:10:16 +0100 [thread overview]
Message-ID: <24493.1523455816@warthog.procyon.org.uk> (raw)
In-Reply-To: <62e9abc2-b639-419c-afa7-e89054f7dce9@canonical.com>
Colin Ian King <colin.king@canonical.com> wrote:
> >> - mask = (1 << nr_slots) - 1;
> >> + mask = (1ULL << nr_slots) - 1;
> >
> > nr_slots cannot be larger than 9, so what I wrote is actually fine and is
> > more efficient on a 32-bit machine.
>
> ok, sorry about the noise.
It would be possible to cast the value to u64 before assigning it, I suppose.
Would that help? E.g.:
mask = (u64)((1 << nr_slots) - 1);
It looks a bit odd, though, since the cast is made implicitly anyway.
David
next prev parent reply other threads:[~2018-04-11 14:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-11 13:26 Colin King
2018-04-11 13:39 ` David Howells
2018-04-11 13:42 ` Colin Ian King
2018-04-11 14:10 ` David Howells [this message]
2018-04-11 14:17 ` Colin Ian King
2018-04-11 15:58 ` Dan Carpenter
2018-04-11 16:03 ` David Howells
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