| Message ID | 1367491439-27629-3-git-send-email-wei.liu2@citrix.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
>>> On 02.05.13 at 12:43, Wei Liu <wei.liu2@citrix.com> wrote: > @@ -934,11 +934,14 @@ static int netbk_count_requests(struct xenvif *vif, > RING_IDX cons = vif->tx.req_cons; > int slots = 0; > int drop_err = 0; > + int more_data; > > if (!(first->flags & XEN_NETTXF_more_data)) > return 0; > > do { > + struct xen_netif_tx_request dropped_tx = { 0 }; > + No need for an initializer here. > if (slots >= work_to_do) { > netdev_err(vif->dev, > "Asked for %d slots but exceeds this limit\n", > @@ -972,6 +975,9 @@ static int netbk_count_requests(struct xenvif *vif, > drop_err = -E2BIG; > } > > + if (drop_err) > + txp = &dropped_tx; > + > memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots), > sizeof(*txp)); > > @@ -1001,7 +1007,13 @@ static int netbk_count_requests(struct xenvif *vif, > netbk_fatal_tx_err(vif); > return -EINVAL; > } > - } while ((txp++)->flags & XEN_NETTXF_more_data); > + > + more_data = txp->flags & XEN_NETTXF_more_data; > + > + if (!drop_err) > + txp++; And no need for the conditional here afaict. Jan > + > + } while (more_data); > > if (drop_err) { > netbk_tx_err(vif, first, cons + slots); -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2013-05-02 at 13:04 +0100, Jan Beulich wrote: > >>> On 02.05.13 at 12:43, Wei Liu <wei.liu2@citrix.com> wrote: > > @@ -934,11 +934,14 @@ static int netbk_count_requests(struct xenvif *vif, > > RING_IDX cons = vif->tx.req_cons; > > int slots = 0; > > int drop_err = 0; > > + int more_data; > > > > if (!(first->flags & XEN_NETTXF_more_data)) > > return 0; > > > > do { > > + struct xen_netif_tx_request dropped_tx = { 0 }; > > + > > No need for an initializer here. > > > if (slots >= work_to_do) { > > netdev_err(vif->dev, > > "Asked for %d slots but exceeds this limit\n", > > @@ -972,6 +975,9 @@ static int netbk_count_requests(struct xenvif *vif, > > drop_err = -E2BIG; > > } > > > > + if (drop_err) > > + txp = &dropped_tx; > > + > > memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots), > > sizeof(*txp)); > > > > @@ -1001,7 +1007,13 @@ static int netbk_count_requests(struct xenvif *vif, > > netbk_fatal_tx_err(vif); > > return -EINVAL; > > } > > - } while ((txp++)->flags & XEN_NETTXF_more_data); > > + > > + more_data = txp->flags & XEN_NETTXF_more_data; > > + > > + if (!drop_err) > > + txp++; > > And no need for the conditional here afaict. I think it is needed, in the case where you've assigned txp = &dropped_tx you don't want to increment txp. Or perhaps it just gets reassigned back to &dropped_tx at the top of the next loop, so the increment doesn't matter. Subtle! I'm happy with whichever way Wei prefers, but it is probably worthy of a comment > > Jan > > > + > > + } while (more_data); > > > > if (drop_err) { > > netbk_tx_err(vif, first, cons + slots); > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 02, 2013 at 04:55:46PM +0100, Ian Campbell wrote: > > > + more_data = txp->flags & XEN_NETTXF_more_data; > > > + > > > + if (!drop_err) > > > + txp++; > > > > And no need for the conditional here afaict. > > I think it is needed, in the case where you've assigned txp = > &dropped_tx you don't want to increment txp. > > Or perhaps it just gets reassigned back to &dropped_tx at the top of the > next loop, so the increment doesn't matter. Subtle! I'm happy with > whichever way Wei prefers, but it is probably worthy of a comment > Yes that's my starting point. I know that txp will always be assigned to &dropped_tx, I just don't feel comfortable incrementing txp in that case. This is really a personal taste thing. :-) Wei. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index c44772d..ce8109f 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -934,11 +934,14 @@ static int netbk_count_requests(struct xenvif *vif, RING_IDX cons = vif->tx.req_cons; int slots = 0; int drop_err = 0; + int more_data; if (!(first->flags & XEN_NETTXF_more_data)) return 0; do { + struct xen_netif_tx_request dropped_tx = { 0 }; + if (slots >= work_to_do) { netdev_err(vif->dev, "Asked for %d slots but exceeds this limit\n", @@ -972,6 +975,9 @@ static int netbk_count_requests(struct xenvif *vif, drop_err = -E2BIG; } + if (drop_err) + txp = &dropped_tx; + memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots), sizeof(*txp)); @@ -1001,7 +1007,13 @@ static int netbk_count_requests(struct xenvif *vif, netbk_fatal_tx_err(vif); return -EINVAL; } - } while ((txp++)->flags & XEN_NETTXF_more_data); + + more_data = txp->flags & XEN_NETTXF_more_data; + + if (!drop_err) + txp++; + + } while (more_data); if (drop_err) { netbk_tx_err(vif, first, cons + slots); @@ -1408,7 +1420,7 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) !list_empty(&netbk->net_schedule_list)) { struct xenvif *vif; struct xen_netif_tx_request txreq; - struct xen_netif_tx_request txfrags[max_skb_slots]; + struct xen_netif_tx_request txfrags[XEN_NETIF_NR_SLOTS_MIN]; struct page *page; struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1]; u16 pending_idx;
Tune xen_netbk_count_requests to not touch working array beyond limit, so that we can make working array size constant. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Wei Liu <wei.liu2@citrix.com> --- drivers/net/xen-netback/netback.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)