From: Andrew Morton <akpm@linux-foundation.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Joe Perches <joe@perches.com>,
Kent Overstreet <kmo@daterainc.com>, Neil Brown <neilb@suse.de>,
linux-bcache@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux-Next <linux-next@vger.kernel.org>
Subject: Re: [PATCH -next 2/2] bcache: Use max_t() when comparing different types
Date: Thu, 6 Feb 2014 12:50:58 -0800 [thread overview]
Message-ID: <20140206125058.8b5d884cca468b9850d5b538@linux-foundation.org> (raw)
In-Reply-To: <CAMuHMdVJ8N7UHWz6aMdurwpKwafb_V0AS7MyUQWftiH9C-8b5A@mail.gmail.com>
On Thu, 6 Feb 2014 21:45:36 +0100 Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > --- a/drivers/md/bcache/btree.c~bcache-drop-l-suffix-when-comparing-ssize_t-with-0-fix
> > +++ a/drivers/md/bcache/btree.c
> > @@ -1805,7 +1805,7 @@ static bool btree_insert_key(struct btre
> >
> > static size_t insert_u64s_remaining(struct btree *b)
> > {
> > - ssize_t ret = bch_btree_keys_u64s_remaining(&b->keys);
> > + size_t ret = bch_btree_keys_u64s_remaining(&b->keys);
> >
> > /*
> > * Might land in the middle of an existing extent and have to split it
> > @@ -1813,7 +1813,7 @@ static size_t insert_u64s_remaining(stru
> > if (b->keys.ops->is_extents)
> > ret -= KEY_MAX_U64S;
>
> I think the reason is the line above: with size_t, ret may become a big
> positive number when the subtraction wraps below zero.
Well, I assumed that case would be a bug - otherwise the programmer
would have commented such a subtlety. Wouldn't he?
> >
> > - return max(ret, 0);
> > + return max_t(size_t, ret, 0);
>
> That part is OK, cfr. my v1 (which I had planned to send out as v3 again).
It needs to be ssize_t.
next prev parent reply other threads:[~2014-02-06 20:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-15 9:06 [PATCH -next 1/2] bcache: Use %zi to format size_t Geert Uytterhoeven
2014-01-15 9:06 ` [PATCH -next 2/2] bcache: Use max_t() when comparing different types Geert Uytterhoeven
2014-01-15 11:06 ` Joe Perches
2014-02-03 13:47 ` Geert Uytterhoeven
2014-02-06 9:00 ` Geert Uytterhoeven
2014-02-06 9:06 ` Joe Perches
2014-02-06 20:38 ` Andrew Morton
2014-02-06 20:45 ` Geert Uytterhoeven
2014-02-06 20:50 ` Andrew Morton [this message]
2014-02-06 20:53 ` Geert Uytterhoeven
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