UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

Merge branch 'xen-netback' 

Paul Durrant says:

====================
xen-netback: fix rx slot estimation

Sander Eikelenboom reported an issue with ring overflow in netback in
3.14-rc3. This turns outo be be because of a bug in the ring slot estimation
code. This patch series fixes the slot estimation, fixes the BUG_ON() that
was supposed to catch the issue that Sander ran into and also makes a small
fix to start_new_rx_buffer().

v3:
 - Added a cap of MAX_SKB_FRAGS to estimate in patch #2

v2:
 - Added BUG_ON() to patch #1
 - Added more explanation to patch #3
====================

Reported-By: Sander Eikelenboom <linux@eikelenboom.it>
Tested-By: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2014-03-29 18:52:04 -04:00
parent 49d8137a40 1425c7a4e8
commit df69491b7d
1 changed files with 29 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/net/xen-netback/netback.c
View File

@ -192,8 +192,8 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head)
* into multiple copies tend to give large frags their
* own buffers as before.
*/
if ((offset + size > MAX_BUFFER_OFFSET) &&
(size <= MAX_BUFFER_OFFSET) && offset && !head)
BUG_ON(size > MAX_BUFFER_OFFSET);
if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head)
return true;
return false;
@ -482,6 +482,8 @@ static void xenvif_rx_action(struct xenvif *vif)
while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
RING_IDX max_slots_needed;
RING_IDX old_req_cons;
RING_IDX ring_slots_used;
int i;
/* We need a cheap worse case estimate for the number of
@ -493,9 +495,28 @@ static void xenvif_rx_action(struct xenvif *vif)
PAGE_SIZE);
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
unsigned int size;
unsigned int offset;
size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
max_slots_needed += DIV_ROUND_UP(size, PAGE_SIZE);
offset = skb_shinfo(skb)->frags[i].page_offset;
/* For a worse-case estimate we need to factor in
* the fragment page offset as this will affect the
* number of times xenvif_gop_frag_copy() will
* call start_new_rx_buffer().
*/
max_slots_needed += DIV_ROUND_UP(offset + size,
PAGE_SIZE);
}
/* To avoid the estimate becoming too pessimal for some
* frontends that limit posted rx requests, cap the estimate
* at MAX_SKB_FRAGS.
*/
if (max_slots_needed > MAX_SKB_FRAGS)
max_slots_needed = MAX_SKB_FRAGS;
/* We may need one more slot for GSO metadata */
if (skb_is_gso(skb) &&
(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
@ -511,8 +532,12 @@ static void xenvif_rx_action(struct xenvif *vif)
vif->rx_last_skb_slots = 0;
sco = (struct skb_cb_overlay *)skb->cb;
old_req_cons = vif->rx.req_cons;
sco->meta_slots_used = xenvif_gop_skb(skb, &npo);
BUG_ON(sco->meta_slots_used > max_slots_needed);
ring_slots_used = vif->rx.req_cons - old_req_cons;
BUG_ON(ring_slots_used > max_slots_needed);
__skb_queue_tail(&rxq, skb);
}