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From: Leon Romanovsky <leon@kernel.org>
To: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Cc: Raju Rangoju <rajur@chelsio.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	yuanxzhang@fudan.edu.cn, Xin Tan <tanxin.ctf@gmail.com>
Subject: Re: [PATCH] cxgb3: Convert from atomic_t to refcount_t on l2t_entry->refcnt
Date: Sun, 18 Jul 2021 13:42:53 +0300	[thread overview]
Message-ID: <YPQFrf7/VYhW47mF@unreal> (raw)
In-Reply-To: <1626516975-42566-1-git-send-email-xiyuyang19@fudan.edu.cn>

On Sat, Jul 17, 2021 at 06:16:15PM +0800, Xiyu Yang wrote:
> refcount_t type and corresponding API can protect refcounters from
> accidental underflow and overflow and further use-after-free situations.
> 
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
> ---
>  drivers/net/ethernet/chelsio/cxgb3/l2t.c | 15 ++++++++-------
>  drivers/net/ethernet/chelsio/cxgb3/l2t.h | 10 +++++++---
>  2 files changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/ethernet/chelsio/cxgb3/l2t.c b/drivers/net/ethernet/chelsio/cxgb3/l2t.c
> index 9749d1239f58..0f2a47bc20d8 100644
> --- a/drivers/net/ethernet/chelsio/cxgb3/l2t.c
> +++ b/drivers/net/ethernet/chelsio/cxgb3/l2t.c
> @@ -225,10 +225,11 @@ static struct l2t_entry *alloc_l2e(struct l2t_data *d)
>  
>  	/* there's definitely a free entry */
>  	for (e = d->rover, end = &d->l2tab[d->nentries]; e != end; ++e)
> -		if (atomic_read(&e->refcnt) == 0)
> +		if (refcount_read(&e->refcnt) == 0)

All those atomic_t to refcount_t patches can't be right, refcount_t can't be 0.

Thanks

      reply	other threads:[~2021-07-18 10:42 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-17 10:16 Xiyu Yang
2021-07-18 10:42 ` Leon Romanovsky [this message]

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