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Merge branch 'xen-netback-fix-issue-introduced-recently'

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Juergen Gross says:

====================
xen/netback: fix issue introduced recently

The fix for XSA-423 introduced a bug which resulted in loss of network
connection in some configurations.

The first patch is fixing the issue, while the second one is removing
a test which isn't needed.
====================

Link: https://lore.kernel.org/r/20230327083646.18690-1-jgross@suse.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Paolo Abeni 2023-03-28 14:16:42 +02:00
commit 917fd7d6cd
2 changed files with 24 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/xen-netback/common.h
View File

@ -166,7 +166,7 @@ struct xenvif_queue { /* Per-queue data for xenvif */
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 */

29
drivers/net/xen-netback/netback.c
View File

@ -334,6 +334,7 @@ static int xenvif_count_requests(struct xenvif_queue *queue,
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 @@ static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
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;
@ -396,11 +399,13 @@ static void xenvif_get_requests(struct xenvif_queue *queue,
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;
@ -413,6 +418,13 @@ static void xenvif_get_requests(struct xenvif_queue *queue,
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 @@ static void xenvif_get_requests(struct xenvif_queue *queue,
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;
@ -441,7 +454,8 @@ static void xenvif_get_requests(struct xenvif_queue *queue,
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;
@ -539,6 +553,13 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue,
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)
@ -1061,10 +1082,6 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
__skb_queue_tail(&queue->tx_queue, skb);
queue->tx.req_cons = idx;
if ((*map_ops >= ARRAY_SIZE(queue->tx_map_ops)) ||
(*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
break;
}
return;