On Tue, Aug 18, 2020 at 7:30 AM Nathan Chancellor
<natechancellor@xxxxxxxxx> wrote:
>
> On Tue, Aug 18, 2020 at 12:03:18AM -0400, Brooke Basile wrote:
> > Clang warns:
> > drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
> > uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
> > if (IS_ERR(bio)) {
> > ^~~~~~~~~~~
> > drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
> > return err;
> > ^~~
> > drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
> > to silence this warning
> > int err;
> > ^
> > = 0
> >
> > Silence this by replacing `err` with `ret`, returning ret = 0 upon
> > success.
> >
> > Signed-off-by: Brooke Basile <brookebasile@xxxxxxxxx>
> > ---
> > drivers/block/rnbd/rnbd-srv.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> > index 0fb94843a495..f515d1a048a9 100644
> > --- a/drivers/block/rnbd/rnbd-srv.c
> > +++ b/drivers/block/rnbd/rnbd-srv.c
> > @@ -123,10 +123,10 @@ static int process_rdma(struct rtrs_srv *sess,
> > struct rnbd_io_private *priv;
> > struct rnbd_srv_sess_dev *sess_dev;
> > u32 dev_id;
> > - int err;
> > struct rnbd_dev_blk_io *io;
> > struct bio *bio;
> > short prio;
> > + int ret = 0;
> >
> > priv = kmalloc(sizeof(*priv), GFP_KERNEL);
> > if (!priv)
> > @@ -138,7 +138,7 @@ static int process_rdma(struct rtrs_srv *sess,
> > if (IS_ERR(sess_dev)) {
> > pr_err_ratelimited("Got I/O request on session %s for unknown device id %d\n",
> > srv_sess->sessname, dev_id);
> > - err = -ENOTCONN;
> > + ret = -ENOTCONN;
> > goto err;
> > }
> >
> > @@ -168,13 +168,13 @@ static int process_rdma(struct rtrs_srv *sess,
> >
> > submit_bio(bio);
> >
> > - return 0;
> > + return ret;
> >
> > sess_dev_put:
> > rnbd_put_sess_dev(sess_dev);
> > err:
> > kfree(priv);
> > - return err;
> > + return ret;
> > }
> >
> > static void destroy_device(struct rnbd_srv_dev *dev)
> > --
> > 2.28.0
> >
>
> I don't think this is a proper fix since the root cause of the warning
> appears to be that we are ignoring the return value of
> rnbd_bio_map_kern. Should we not set err to that value like this
> (completely untested)?
>
> Cheers,
> Nathan
Thanks Nathan, thanks Brooke,
I agree with Nathan, the problem is we forgot to set the err before
"goto sess_dev_put".
Nathan's patch is simpler, less code of change.
>
> diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> index 0fb94843a495..1b71cb2a885d 100644
> --- a/drivers/block/rnbd/rnbd-srv.c
> +++ b/drivers/block/rnbd/rnbd-srv.c
> @@ -148,7 +148,8 @@ static int process_rdma(struct rtrs_srv *sess,
> /* Generate bio with pages pointing to the rdma buffer */
> bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
> if (IS_ERR(bio)) {
> - rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", PTR_ERR(bio));
> + err = PTR_ERR(bio);
> + rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", err);
> goto sess_dev_put;
> }
>
Nathan, could you send a formal patch?
Thanks
