From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Date: Tue, 19 Feb 2019 16:35:34 +0000 Subject: Re: [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processe Message-Id: <20190219113510-mutt-send-email-mst@kernel.org> List-Id: References: <20190219135713.10426-1-colin.king@canonical.com> In-Reply-To: <20190219135713.10426-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Colin King Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org On Tue, Feb 19, 2019 at 01:57:13PM +0000, Colin King wrote: > From: Colin Ian King > > Currently the loop that calls log_write_hva on each iovec is never > executed because of an incorrect error check on the return from the > call to translate_desc. The check should be checking for a -ve error > return and because it makes no sense to iterate over zero items, the > checks should also check for zero too. > > Detected by CoverityScan, CID#1476969 ("Logically dead code") > > Fixes: cc5e71075947 ("vhost: log dirty page correctly") > Signed-off-by: Colin Ian King Jason posted a similar patch recently. Are you happy with that one? > --- > drivers/vhost/vhost.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 24a129fcdd61..a9a1709a859a 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1788,7 +1788,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len) > > ret = translate_desc(vq, (uintptr_t)vq->used + used_offset, > len, iov, 64, VHOST_ACCESS_WO); > - if (ret) > + if (ret <= 0) > return ret; > > for (i = 0; i < ret; i++) { > -- > 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processed Date: Tue, 19 Feb 2019 11:35:34 -0500 Message-ID: <20190219113510-mutt-send-email-mst@kernel.org> References: <20190219135713.10426-1-colin.king@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org To: Colin King Return-path: Content-Disposition: inline In-Reply-To: <20190219135713.10426-1-colin.king@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Tue, Feb 19, 2019 at 01:57:13PM +0000, Colin King wrote: > From: Colin Ian King > > Currently the loop that calls log_write_hva on each iovec is never > executed because of an incorrect error check on the return from the > call to translate_desc. The check should be checking for a -ve error > return and because it makes no sense to iterate over zero items, the > checks should also check for zero too. > > Detected by CoverityScan, CID#1476969 ("Logically dead code") > > Fixes: cc5e71075947 ("vhost: log dirty page correctly") > Signed-off-by: Colin Ian King Jason posted a similar patch recently. Are you happy with that one? > --- > drivers/vhost/vhost.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 24a129fcdd61..a9a1709a859a 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1788,7 +1788,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len) > > ret = translate_desc(vq, (uintptr_t)vq->used + used_offset, > len, iov, 64, VHOST_ACCESS_WO); > - if (ret) > + if (ret <= 0) > return ret; > > for (i = 0; i < ret; i++) { > -- > 2.20.1