From ea08eeccae9297f7aabd2ef7f0c2517ac4549acc Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:18:26 +0000
Subject: [PATCH] write in 30M
---
kernel/drivers/net/xen-netback/netback.c | 46 +++++++++++++++++++++++++++++++++++-----------
1 files changed, 35 insertions(+), 11 deletions(-)
diff --git a/kernel/drivers/net/xen-netback/netback.c b/kernel/drivers/net/xen-netback/netback.c
index f9373a8..1c366dd 100644
--- a/kernel/drivers/net/xen-netback/netback.c
+++ b/kernel/drivers/net/xen-netback/netback.c
@@ -334,6 +334,7 @@
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)
@@ -361,6 +362,8 @@
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;
@@ -393,14 +396,16 @@
struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
struct xen_netif_tx_request *txp = first;
- nr_slots = shinfo->nr_frags + 1;
+ nr_slots = shinfo->nr_frags + frag_overflow + 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;
@@ -413,6 +418,13 @@
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;
@@ -420,7 +432,8 @@
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;
@@ -441,15 +454,16 @@
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;
}
}
- for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
- shinfo->nr_frags++, gop++) {
+ for (shinfo->nr_frags = 0; nr_slots > 0 && shinfo->nr_frags < MAX_SKB_FRAGS;
+ shinfo->nr_frags++, gop++, nr_slots--) {
index = pending_index(queue->pending_cons++);
pending_idx = queue->pending_ring[index];
xenvif_tx_create_map_op(queue, pending_idx, txp,
@@ -462,12 +476,12 @@
txp++;
}
- if (frag_overflow) {
+ if (nr_slots > 0) {
shinfo = skb_shinfo(nskb);
frags = shinfo->frags;
- for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
+ for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
shinfo->nr_frags++, txp++, gop++) {
index = pending_index(queue->pending_cons++);
pending_idx = queue->pending_ring[index];
@@ -478,6 +492,11 @@
}
skb_shinfo(skb)->frag_list = nskb;
+ } else if (nskb) {
+ /* A frag_list skb was allocated but it is no longer needed
+ * because enough slots were converted to copy ops above.
+ */
+ kfree_skb(nskb);
}
(*copy_ops) = cop - queue->tx_copy_ops;
@@ -539,6 +558,13 @@
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)
@@ -975,10 +1001,8 @@
/* No crossing a page as the payload mustn't fragment. */
if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
- netdev_err(queue->vif->dev,
- "txreq.offset: %u, size: %u, end: %lu\n",
- txreq.offset, txreq.size,
- (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
+ netdev_err(queue->vif->dev, "Cross page boundary, txreq.offset: %u, size: %u\n",
+ txreq.offset, txreq.size);
xenvif_fatal_tx_err(queue->vif);
break;
}
--
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