From: Juergen Gross jgross@suse.com
commit 05310f31ca74673a96567fb14637b7d5d6c82ea5 upstream.
Fix xenvif_get_requests() not to do grant copy operations across local page boundaries. This requires to double the maximum number of copy operations per queue, as each copy could now be split into 2.
Make sure that struct xenvif_tx_cb doesn't grow too large.
Cc: stable@vger.kernel.org Fixes: ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area") Signed-off-by: Juergen Gross jgross@suse.com Reviewed-by: Paul Durrant paul@xen.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/xen-netback/common.h | 2 +- drivers/net/xen-netback/netback.c | 25 +++++++++++++++++++++++-- 2 files changed, 24 insertions(+), 3 deletions(-)
--- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -166,7 +166,7 @@ struct xenvif_queue { /* Per-queue data struct pending_tx_info pending_tx_info[MAX_PENDING_REQS]; grant_handle_t grant_tx_handle[MAX_PENDING_REQS];
- struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS]; + struct gnttab_copy tx_copy_ops[2 * MAX_PENDING_REQS]; struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS]; struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS]; /* passed to gnttab_[un]map_refs with pages under (un)mapping */ --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -327,6 +327,7 @@ static int xenvif_count_requests(struct struct xenvif_tx_cb { u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1]; u8 copy_count; + u32 split_mask; };
#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb) @@ -354,6 +355,8 @@ static inline struct sk_buff *xenvif_all struct sk_buff *skb = alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN, GFP_ATOMIC | __GFP_NOWARN); + + BUILD_BUG_ON(sizeof(*XENVIF_TX_CB(skb)) > sizeof(skb->cb)); if (unlikely(skb == NULL)) return NULL;
@@ -389,11 +392,13 @@ static void xenvif_get_requests(struct x nr_slots = shinfo->nr_frags + 1;
copy_count(skb) = 0; + XENVIF_TX_CB(skb)->split_mask = 0;
/* Create copy ops for exactly data_len bytes into the skb head. */ __skb_put(skb, data_len); while (data_len > 0) { int amount = data_len > txp->size ? txp->size : data_len; + bool split = false;
cop->source.u.ref = txp->gref; cop->source.domid = queue->vif->domid; @@ -406,6 +411,13 @@ static void xenvif_get_requests(struct x cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb) - data_len);
+ /* Don't cross local page boundary! */ + if (cop->dest.offset + amount > XEN_PAGE_SIZE) { + amount = XEN_PAGE_SIZE - cop->dest.offset; + XENVIF_TX_CB(skb)->split_mask |= 1U << copy_count(skb); + split = true; + } + cop->len = amount; cop->flags = GNTCOPY_source_gref;
@@ -413,7 +425,8 @@ static void xenvif_get_requests(struct x pending_idx = queue->pending_ring[index]; callback_param(queue, pending_idx).ctx = NULL; copy_pending_idx(skb, copy_count(skb)) = pending_idx; - copy_count(skb)++; + if (!split) + copy_count(skb)++;
cop++; data_len -= amount; @@ -434,7 +447,8 @@ static void xenvif_get_requests(struct x nr_slots--; } else { /* The copy op partially covered the tx_request. - * The remainder will be mapped. + * The remainder will be mapped or copied in the next + * iteration. */ txp->offset += amount; txp->size -= amount; @@ -532,6 +546,13 @@ static int xenvif_tx_check_gop(struct xe pending_idx = copy_pending_idx(skb, i);
newerr = (*gopp_copy)->status; + + /* Split copies need to be handled together. */ + if (XENVIF_TX_CB(skb)->split_mask & (1U << i)) { + (*gopp_copy)++; + if (!newerr) + newerr = (*gopp_copy)->status; + } if (likely(!newerr)) { /* The first frag might still have this slot mapped */ if (i < copy_count(skb) - 1 || !sharedslot)