* [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers
@ 2013-11-28 11:30 Michael S. Tsirkin
2013-11-28 11:30 ` [PATCH v2 2/2] virtio-net: make all RX paths handle erors consistently Michael S. Tsirkin
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Michael S. Tsirkin @ 2013-11-28 11:30 UTC (permalink / raw)
To: linux-kernel; +Cc: Michael Dalton, netdev, virtualization, Eric Dumazet
Eric Dumazet noticed that if we encounter an error
when processing a mergeable buffer, we don't
dequeue all of the buffers from this packet,
the result is almost sure to be loss of networking.
Jason Wang noticed that we also leak a page and that we don't decrement
the rq buf count, so we won't repost buffers (a resource leak).
Fix both issues.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael Dalton <mwdalton@google.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
Stable patch will be sent later.
drivers/net/virtio_net.c | 82 ++++++++++++++++++++++++++++++------------------
1 file changed, 51 insertions(+), 31 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7bab4de..5408de6 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -299,35 +299,47 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
return skb;
}
-static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb)
+static struct sk_buff *receive_mergeable(struct net_device *dev,
+ struct receive_queue *rq,
+ void *buf,
+ unsigned int len)
{
- struct skb_vnet_hdr *hdr = skb_vnet_hdr(head_skb);
+ struct skb_vnet_hdr *hdr = buf;
+ int num_buf = hdr->mhdr.num_buffers;
+ struct page *page = virt_to_head_page(buf);
+ int offset = buf - page_address(page);
+ struct sk_buff *head_skb = page_to_skb(rq, page, offset, len,
+ MERGE_BUFFER_LEN);
struct sk_buff *curr_skb = head_skb;
- char *buf;
- struct page *page;
- int num_buf, len, offset;
- num_buf = hdr->mhdr.num_buffers;
+ if (unlikely(!curr_skb))
+ goto err_skb;
+
while (--num_buf) {
- int num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
+ int num_skb_frags;
+
buf = virtqueue_get_buf(rq->vq, &len);
if (unlikely(!buf)) {
- pr_debug("%s: rx error: %d buffers missing\n",
- head_skb->dev->name, hdr->mhdr.num_buffers);
- head_skb->dev->stats.rx_length_errors++;
- return -EINVAL;
+ pr_debug("%s: rx error: %d buffers out of %d missing\n",
+ dev->name, num_buf, hdr->mhdr.num_buffers);
+ dev->stats.rx_length_errors++;
+ goto err_buf;
}
if (unlikely(len > MERGE_BUFFER_LEN)) {
pr_debug("%s: rx error: merge buffer too long\n",
- head_skb->dev->name);
+ dev->name);
len = MERGE_BUFFER_LEN;
}
+
+ page = virt_to_head_page(buf);
+ --rq->num;
+
+ num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
- if (unlikely(!nskb)) {
- head_skb->dev->stats.rx_dropped++;
- return -ENOMEM;
- }
+
+ if (unlikely(!nskb))
+ goto err_skb;
if (curr_skb == head_skb)
skb_shinfo(curr_skb)->frag_list = nskb;
else
@@ -341,8 +353,7 @@ static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb)
head_skb->len += len;
head_skb->truesize += MERGE_BUFFER_LEN;
}
- page = virt_to_head_page(buf);
- offset = buf - (char *)page_address(page);
+ offset = buf - page_address(page);
if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
put_page(page);
skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
@@ -351,9 +362,28 @@ static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb)
skb_add_rx_frag(curr_skb, num_skb_frags, page,
offset, len, MERGE_BUFFER_LEN);
}
+ }
+
+ return head_skb;
+
+err_skb:
+ put_page(page);
+ while (--num_buf) {
+ buf = virtqueue_get_buf(rq->vq, &len);
+ if (unlikely(!buf)) {
+ pr_debug("%s: rx error: %d buffers missing\n",
+ dev->name, num_buf);
+ dev->stats.rx_length_errors++;
+ break;
+ }
+ page = virt_to_head_page(buf);
+ put_page(page);
--rq->num;
}
- return 0;
+err_buf:
+ dev->stats.rx_dropped++;
+ dev_kfree_skb(head_skb);
+ return NULL;
}
static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
@@ -382,19 +412,9 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
len -= sizeof(struct virtio_net_hdr);
skb_trim(skb, len);
} else if (vi->mergeable_rx_bufs) {
- struct page *page = virt_to_head_page(buf);
- skb = page_to_skb(rq, page,
- (char *)buf - (char *)page_address(page),
- len, MERGE_BUFFER_LEN);
- if (unlikely(!skb)) {
- dev->stats.rx_dropped++;
- put_page(page);
+ skb = receive_mergeable(dev, rq, buf, len);
+ if (unlikely(!skb))
return;
- }
- if (receive_mergeable(rq, skb)) {
- dev_kfree_skb(skb);
- return;
- }
} else {
page = buf;
skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
--
MST
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 2/2] virtio-net: make all RX paths handle erors consistently
2013-11-28 11:30 [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers Michael S. Tsirkin
@ 2013-11-28 11:30 ` Michael S. Tsirkin
2013-12-02 1:28 ` David Miller
2013-11-29 10:13 ` [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers Jason Wang
2013-12-02 1:27 ` David Miller
2 siblings, 1 reply; 5+ messages in thread
From: Michael S. Tsirkin @ 2013-11-28 11:30 UTC (permalink / raw)
To: linux-kernel; +Cc: netdev, virtualization
receive mergeable now handles errors internally.
Do same for big and small packet paths, otherwise
the logic is too hard to follow.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
I don't see a bug in current code but I think it's still
a good idea to queue this in 3.13, for consistency.
drivers/net/virtio_net.c | 54 +++++++++++++++++++++++++++++++++---------------
1 file changed, 37 insertions(+), 17 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5408de6..4b01946 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -299,6 +299,35 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
return skb;
}
+static struct sk_buff *receive_small(void *buf, unsigned int len)
+{
+ struct sk_buff * skb = buf;
+
+ len -= sizeof(struct virtio_net_hdr);
+ skb_trim(skb, len);
+
+ return skb;
+}
+
+static struct sk_buff *receive_big(struct net_device *dev,
+ struct receive_queue *rq,
+ void *buf,
+ unsigned int len)
+{
+ struct page *page = buf;
+ struct sk_buff *skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
+
+ if (unlikely(!skb))
+ goto err;
+
+ return skb;
+
+err:
+ dev->stats.rx_dropped++;
+ give_pages(rq, page);
+ return NULL;
+}
+
static struct sk_buff *receive_mergeable(struct net_device *dev,
struct receive_queue *rq,
void *buf,
@@ -392,7 +421,6 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
struct net_device *dev = vi->dev;
struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
struct sk_buff *skb;
- struct page *page;
struct skb_vnet_hdr *hdr;
if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
@@ -407,23 +435,15 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
return;
}
- if (!vi->mergeable_rx_bufs && !vi->big_packets) {
- skb = buf;
- len -= sizeof(struct virtio_net_hdr);
- skb_trim(skb, len);
- } else if (vi->mergeable_rx_bufs) {
+ if (vi->mergeable_rx_bufs)
skb = receive_mergeable(dev, rq, buf, len);
- if (unlikely(!skb))
- return;
- } else {
- page = buf;
- skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
- if (unlikely(!skb)) {
- dev->stats.rx_dropped++;
- give_pages(rq, page);
- return;
- }
- }
+ else if (vi->big_packets)
+ skb = receive_big(dev, rq, buf, len);
+ else
+ skb = receive_small(buf, len);
+
+ if (unlikely(!skb))
+ return;
hdr = skb_vnet_hdr(skb);
--
MST
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers
2013-11-28 11:30 [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers Michael S. Tsirkin
2013-11-28 11:30 ` [PATCH v2 2/2] virtio-net: make all RX paths handle erors consistently Michael S. Tsirkin
@ 2013-11-29 10:13 ` Jason Wang
2013-12-02 1:27 ` David Miller
2 siblings, 0 replies; 5+ messages in thread
From: Jason Wang @ 2013-11-29 10:13 UTC (permalink / raw)
To: Michael S. Tsirkin, linux-kernel
Cc: netdev, Eric Dumazet, Michael Dalton, virtualization
On 11/28/2013 07:30 PM, Michael S. Tsirkin wrote:
> Eric Dumazet noticed that if we encounter an error
> when processing a mergeable buffer, we don't
> dequeue all of the buffers from this packet,
> the result is almost sure to be loss of networking.
>
> Jason Wang noticed that we also leak a page and that we don't decrement
> the rq buf count, so we won't repost buffers (a resource leak).
>
> Fix both issues.
>
> Cc: Rusty Russell <rusty@rustcorp.com.au>
> Cc: Michael Dalton <mwdalton@google.com>
> Reported-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
> Stable patch will be sent later.
>
> drivers/net/virtio_net.c | 82 ++++++++++++++++++++++++++++++------------------
> 1 file changed, 51 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 7bab4de..5408de6 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -299,35 +299,47 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
> return skb;
> }
>
> -static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb)
> +static struct sk_buff *receive_mergeable(struct net_device *dev,
> + struct receive_queue *rq,
> + void *buf,
> + unsigned int len)
> {
> - struct skb_vnet_hdr *hdr = skb_vnet_hdr(head_skb);
> + struct skb_vnet_hdr *hdr = buf;
> + int num_buf = hdr->mhdr.num_buffers;
> + struct page *page = virt_to_head_page(buf);
> + int offset = buf - page_address(page);
> + struct sk_buff *head_skb = page_to_skb(rq, page, offset, len,
> + MERGE_BUFFER_LEN);
> struct sk_buff *curr_skb = head_skb;
> - char *buf;
> - struct page *page;
> - int num_buf, len, offset;
>
> - num_buf = hdr->mhdr.num_buffers;
> + if (unlikely(!curr_skb))
> + goto err_skb;
> +
> while (--num_buf) {
> - int num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
> + int num_skb_frags;
> +
> buf = virtqueue_get_buf(rq->vq, &len);
> if (unlikely(!buf)) {
> - pr_debug("%s: rx error: %d buffers missing\n",
> - head_skb->dev->name, hdr->mhdr.num_buffers);
> - head_skb->dev->stats.rx_length_errors++;
> - return -EINVAL;
> + pr_debug("%s: rx error: %d buffers out of %d missing\n",
> + dev->name, num_buf, hdr->mhdr.num_buffers);
> + dev->stats.rx_length_errors++;
> + goto err_buf;
> }
> if (unlikely(len > MERGE_BUFFER_LEN)) {
> pr_debug("%s: rx error: merge buffer too long\n",
> - head_skb->dev->name);
> + dev->name);
> len = MERGE_BUFFER_LEN;
> }
> +
> + page = virt_to_head_page(buf);
> + --rq->num;
> +
> + num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
> if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
> struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
> - if (unlikely(!nskb)) {
> - head_skb->dev->stats.rx_dropped++;
> - return -ENOMEM;
> - }
> +
> + if (unlikely(!nskb))
> + goto err_skb;
> if (curr_skb == head_skb)
> skb_shinfo(curr_skb)->frag_list = nskb;
> else
> @@ -341,8 +353,7 @@ static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb)
> head_skb->len += len;
> head_skb->truesize += MERGE_BUFFER_LEN;
> }
> - page = virt_to_head_page(buf);
> - offset = buf - (char *)page_address(page);
> + offset = buf - page_address(page);
> if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
> put_page(page);
> skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
> @@ -351,9 +362,28 @@ static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb)
> skb_add_rx_frag(curr_skb, num_skb_frags, page,
> offset, len, MERGE_BUFFER_LEN);
> }
> + }
> +
> + return head_skb;
> +
> +err_skb:
> + put_page(page);
> + while (--num_buf) {
> + buf = virtqueue_get_buf(rq->vq, &len);
> + if (unlikely(!buf)) {
> + pr_debug("%s: rx error: %d buffers missing\n",
> + dev->name, num_buf);
> + dev->stats.rx_length_errors++;
> + break;
> + }
> + page = virt_to_head_page(buf);
> + put_page(page);
> --rq->num;
> }
> - return 0;
> +err_buf:
> + dev->stats.rx_dropped++;
> + dev_kfree_skb(head_skb);
> + return NULL;
> }
>
> static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
> @@ -382,19 +412,9 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
> len -= sizeof(struct virtio_net_hdr);
> skb_trim(skb, len);
> } else if (vi->mergeable_rx_bufs) {
> - struct page *page = virt_to_head_page(buf);
> - skb = page_to_skb(rq, page,
> - (char *)buf - (char *)page_address(page),
> - len, MERGE_BUFFER_LEN);
> - if (unlikely(!skb)) {
> - dev->stats.rx_dropped++;
> - put_page(page);
> + skb = receive_mergeable(dev, rq, buf, len);
> + if (unlikely(!skb))
> return;
> - }
> - if (receive_mergeable(rq, skb)) {
> - dev_kfree_skb(skb);
> - return;
> - }
> } else {
> page = buf;
> skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
Acked-by: Jason Wang <jasowang@redhat.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers
2013-11-28 11:30 [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers Michael S. Tsirkin
2013-11-28 11:30 ` [PATCH v2 2/2] virtio-net: make all RX paths handle erors consistently Michael S. Tsirkin
2013-11-29 10:13 ` [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers Jason Wang
@ 2013-12-02 1:27 ` David Miller
2 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2013-12-02 1:27 UTC (permalink / raw)
To: mst; +Cc: mwdalton, netdev, linux-kernel, virtualization, edumazet
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Thu, 28 Nov 2013 13:30:55 +0200
> Eric Dumazet noticed that if we encounter an error
> when processing a mergeable buffer, we don't
> dequeue all of the buffers from this packet,
> the result is almost sure to be loss of networking.
>
> Jason Wang noticed that we also leak a page and that we don't decrement
> the rq buf count, so we won't repost buffers (a resource leak).
>
> Fix both issues.
>
> Cc: Rusty Russell <rusty@rustcorp.com.au>
> Cc: Michael Dalton <mwdalton@google.com>
> Reported-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Applied.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-12-02 1:28 UTC | newest]
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2013-11-28 11:30 [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers Michael S. Tsirkin
2013-11-28 11:30 ` [PATCH v2 2/2] virtio-net: make all RX paths handle erors consistently Michael S. Tsirkin
2013-12-02 1:28 ` David Miller
2013-11-29 10:13 ` [PATCH v2 1/2] virtio_net: fix error handling for mergeable buffers Jason Wang
2013-12-02 1:27 ` David Miller
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