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[79.178.32.166]) by smtp.gmail.com with ESMTPSA id o83sm14758474wme.21.2020.12.27.01.40.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 27 Dec 2020 01:40:20 -0800 (PST) Date: Sun, 27 Dec 2020 04:40:17 -0500 From: "Michael S. Tsirkin" To: wangyunjian Cc: netdev@vger.kernel.org, jasowang@redhat.com, willemdebruijn.kernel@gmail.com, virtualization@lists.linux-foundation.org, jerry.lilijun@huawei.com, chenchanghu@huawei.com, xudingke@huawei.com, brian.huangbin@huawei.com Subject: Re: [PATCH net v2] tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS Message-ID: <20201227044010-mutt-send-email-mst@kernel.org> References: <1608864736-24332-1-git-send-email-wangyunjian@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1608864736-24332-1-git-send-email-wangyunjian@huawei.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Dec 25, 2020 at 10:52:16AM +0800, wangyunjian wrote: > From: Yunjian Wang > > Currently the tun_napi_alloc_frags() function returns -ENOMEM when the > number of iovs exceeds MAX_SKB_FRAGS + 1. However this is inappropriate, > we should use -EMSGSIZE instead of -ENOMEM. > > The following distinctions are matters: > 1. the caller need to drop the bad packet when -EMSGSIZE is returned, > which means meeting a persistent failure. > 2. the caller can try again when -ENOMEM is returned, which means > meeting a transient failure. > > Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") > Signed-off-by: Yunjian Wang > Acked-by: Willem de Bruijn Acked-by: Michael S. Tsirkin > --- > v2: > * update commit log suggested by Willem de Bruijn > --- > drivers/net/tun.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 2dc1988a8973..15c6dd7fb04c 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1365,7 +1365,7 @@ static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile, > int i; > > if (it->nr_segs > MAX_SKB_FRAGS + 1) > - return ERR_PTR(-ENOMEM); > + return ERR_PTR(-EMSGSIZE); > > local_bh_disable(); > skb = napi_get_frags(&tfile->napi); > -- > 2.23.0