| Message ID | 20230925103057.104541-1-sgarzare@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vringh: don't use vringh_kiov_advance() in vringh_iov_xfer() | expand |
On Mon, Sep 25, 2023 at 6:31 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > > In the while loop of vringh_iov_xfer(), `partlen` could be 0 if one of > the `iov` has 0 lenght. > In this case, we should skip the iov and go to the next one. > But calling vringh_kiov_advance() with 0 lenght does not cause the > advancement, since it returns immediately if asked to advance by 0 bytes. > > Let's restore the code that was there before commit b8c06ad4d67d > ("vringh: implement vringh_kiov_advance()"), avoiding using > vringh_kiov_advance(). > > Fixes: b8c06ad4d67d ("vringh: implement vringh_kiov_advance()") > Cc: stable@vger.kernel.org > Reported-by: Jason Wang <jasowang@redhat.com> > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Thanks > --- > drivers/vhost/vringh.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c > index 955d938eb663..7b8fd977f71c 100644 > --- a/drivers/vhost/vringh.c > +++ b/drivers/vhost/vringh.c > @@ -123,8 +123,18 @@ static inline ssize_t vringh_iov_xfer(struct vringh *vrh, > done += partlen; > len -= partlen; > ptr += partlen; > + iov->consumed += partlen; > + iov->iov[iov->i].iov_len -= partlen; > + iov->iov[iov->i].iov_base += partlen; > > - vringh_kiov_advance(iov, partlen); > + if (!iov->iov[iov->i].iov_len) { > + /* Fix up old iov element then increment. */ > + iov->iov[iov->i].iov_len = iov->consumed; > + iov->iov[iov->i].iov_base -= iov->consumed; > + > + iov->consumed = 0; > + iov->i++; > + } > } > return done; > } > -- > 2.41.0 >
Hello: This patch was applied to netdev/net.git (main) by David S. Miller <davem@davemloft.net>: On Mon, 25 Sep 2023 12:30:57 +0200 you wrote: > In the while loop of vringh_iov_xfer(), `partlen` could be 0 if one of > the `iov` has 0 lenght. > In this case, we should skip the iov and go to the next one. > But calling vringh_kiov_advance() with 0 lenght does not cause the > advancement, since it returns immediately if asked to advance by 0 bytes. > > Let's restore the code that was there before commit b8c06ad4d67d > ("vringh: implement vringh_kiov_advance()"), avoiding using > vringh_kiov_advance(). > > [...] Here is the summary with links: - vringh: don't use vringh_kiov_advance() in vringh_iov_xfer() https://git.kernel.org/netdev/net/c/7aed44babc7f You are awesome, thank you!
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 955d938eb663..7b8fd977f71c 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -123,8 +123,18 @@ static inline ssize_t vringh_iov_xfer(struct vringh *vrh, done += partlen; len -= partlen; ptr += partlen; + iov->consumed += partlen; + iov->iov[iov->i].iov_len -= partlen; + iov->iov[iov->i].iov_base += partlen; - vringh_kiov_advance(iov, partlen); + if (!iov->iov[iov->i].iov_len) { + /* Fix up old iov element then increment. */ + iov->iov[iov->i].iov_len = iov->consumed; + iov->iov[iov->i].iov_base -= iov->consumed; + + iov->consumed = 0; + iov->i++; + } } return done; }
In the while loop of vringh_iov_xfer(), `partlen` could be 0 if one of the `iov` has 0 lenght. In this case, we should skip the iov and go to the next one. But calling vringh_kiov_advance() with 0 lenght does not cause the advancement, since it returns immediately if asked to advance by 0 bytes. Let's restore the code that was there before commit b8c06ad4d67d ("vringh: implement vringh_kiov_advance()"), avoiding using vringh_kiov_advance(). Fixes: b8c06ad4d67d ("vringh: implement vringh_kiov_advance()") Cc: stable@vger.kernel.org Reported-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> --- drivers/vhost/vringh.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)