From: Jakub Kicinski <kuba@kernel.org>
To: Guo Ren <guoren@kernel.org>
Cc: andriy.shevchenko@linux.intel.com, davem@davemloft.net,
edumazet@google.com, pabeni@redhat.com, linux@rasmusvillemoes.dk,
yury.norov@gmail.com, caraitto@google.com, willemb@google.com,
jonolson@google.com, amritha.nambiar@intel.com,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Guo Ren <guoren@linux.alibaba.com>
Subject: Re: [PATCH V2 1/2] net: Fixup netif_attrmask_next_and warning
Date: Fri, 14 Oct 2022 08:52:19 -0700 [thread overview]
Message-ID: <20221014085219.635d25cd@kernel.org> (raw)
In-Reply-To: <CAJF2gTQyMHNHLizeU-gvUdA5hRLUWxvHXuVVqSoPg3M_WxPPdw@mail.gmail.com>
On Fri, 14 Oct 2022 14:38:56 +0800 Guo Ren wrote:
> > This does not look equivalent, have you tested it?
> >
> > nr_ids is unsigned, doesn't it mean we'll never enter the loop?
>
> Yes, you are right. Any unsigned int would break the result.
> (gdb) p (int)-1 < (int)2
> $1 = 1
> (gdb) p (int)-1 < (unsigned int)2
> $2 = 0
> (gdb) p (unsigned int)-1 < (int)2
> $4 = 0
>
> So it should be:
> - for (j = -1; j = netif_attrmask_next_and(j, online_mask, mask, nr_ids),
> - j < nr_ids;) {
> + for (j = -1; j < (int)nr_ids;
> + j = netif_attrmask_next_and(j, online_mask, mask, nr_ids)) {
>
> Right? Of cause, nr_ids couldn't be 0xffffffff (-1).
No. You can't enter the loop with -1 as the iterator either.
Let's move on.
next prev parent reply other threads:[~2022-10-14 15:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-14 3:04 [PATCH V2 0/2] net: Fixup cpu_mask usage guoren
2022-10-14 3:04 ` [PATCH V2 1/2] net: Fixup netif_attrmask_next_and warning guoren
2022-10-14 3:35 ` Jakub Kicinski
2022-10-14 3:39 ` Jakub Kicinski
2022-10-14 4:42 ` Yury Norov
2022-10-14 6:42 ` Guo Ren
2022-10-14 16:03 ` Jakub Kicinski
2022-10-14 16:16 ` Yury Norov
2022-10-14 18:03 ` Jakub Kicinski
2022-10-15 1:41 ` Guo Ren
2022-10-14 6:38 ` Guo Ren
2022-10-14 15:52 ` Jakub Kicinski [this message]
2022-10-15 1:38 ` Guo Ren
2022-10-14 10:00 ` Andy Shevchenko
2022-10-14 10:04 ` Guo Ren
2022-10-14 3:04 ` [PATCH V2 2/2] net: Fixup virtnet_set_affinity() cause cpumask warning guoren
2022-10-14 10:00 ` Andy Shevchenko
2022-10-14 10:04 ` Guo Ren
2022-10-17 1:58 ` Xuan Zhuo
2022-10-17 2:46 ` Guo Ren
2022-10-17 2:58 ` Xuan Zhuo
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