On Thu, Sep 26, 2019 at 12:21:12AM +0100, Al Viro wrote: > On Wed, Sep 25, 2019 at 06:04:13PM -0500, Navid Emamdoost wrote: > > In qrtr_tun_read_iter we need an error handling path to appropriately > > release skb in cases of error. > > Release _what_ skb? It is not a leak clearly! My bad ... > > > Signed-off-by: Navid Emamdoost <[email protected]> > > --- > > net/qrtr/tun.c | 13 +++++++++---- > > 1 file changed, 9 insertions(+), 4 deletions(-) > > > > diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c > > index e35869e81766..0f6e6d1d2901 100644 > > --- a/net/qrtr/tun.c > > +++ b/net/qrtr/tun.c > > @@ -54,19 +54,24 @@ static ssize_t qrtr_tun_read_iter(struct kiocb *iocb, > > struct iov_iter *to) > > int count; > > > > while (!(skb = skb_dequeue(&tun->queue))) { > > The body of the loop is entered only if the loop condition has > evaluated true. In this case, it means that the value of > !(skb = skb_dequeue(&tun->queue)) > had been true, i.e. the value of > skb = skb_dequeue(&tun->queue) > has been NULL, i.e. that skb_dequeue() has returned NULL, which had > been copied into skb. > > In other words, in the body of that loop we have skb equal to NULL. > > > - if (filp->f_flags & O_NONBLOCK) > > - return -EAGAIN; > > + if (filp->f_flags & O_NONBLOCK) { > > + count = -EAGAIN; > > + goto out; > > + } > > > > /* Wait until we get data or the endpoint goes away */ > > if (wait_event_interruptible(tun->readq, > > - !skb_queue_empty(&tun->queue))) > > - return -ERESTARTSYS; > > + !skb_queue_empty(&tun->queue))) { > > + count = -ERESTARTSYS; > > + goto out; > > + } > > } > > The meaning of that loop is fairly clear, isn't it? Keep looking int > tun->queue until an skb shows up there. If it's not immediately there, > fail with -EAGAIN for non-blocking files and wait on tun->readq until > some skb arrives.
Thanks for the explainations. Navid.
