Ian Campbell
2012-Oct-10 13:48 UTC
[PATCH V2] xen: netback: handle compound page fragments on transmit.
An SKB paged fragment can consist of a compound page with order > 0.
However the netchannel protocol deals only in PAGE_SIZE frames.
Handle this in netbk_gop_frag_copy and xen_netbk_count_skb_slots by
iterating over the frames which make up the page.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
---
v2: Only move to next frame if there is data remaining.
---
drivers/net/xen-netback/netback.c | 40 ++++++++++++++++++++++++++++++++----
1 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/drivers/net/xen-netback/netback.c
b/drivers/net/xen-netback/netback.c
index 4ebfcf3..f2d6b78 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -335,21 +335,35 @@ unsigned int xen_netbk_count_skb_slots(struct xenvif *vif,
struct sk_buff *skb)
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+ unsigned long offset = skb_shinfo(skb)->frags[i].page_offset;
unsigned long bytes;
+
+ offset &= ~PAGE_MASK;
+
while (size > 0) {
+ BUG_ON(offset >= PAGE_SIZE);
BUG_ON(copy_off > MAX_BUFFER_OFFSET);
- if (start_new_rx_buffer(copy_off, size, 0)) {
+ bytes = PAGE_SIZE - offset;
+
+ if (bytes > size)
+ bytes = size;
+
+ if (start_new_rx_buffer(copy_off, bytes, 0)) {
count++;
copy_off = 0;
}
- bytes = size;
if (copy_off + bytes > MAX_BUFFER_OFFSET)
bytes = MAX_BUFFER_OFFSET - copy_off;
copy_off += bytes;
+
+ offset += bytes;
size -= bytes;
+
+ if (offset == PAGE_SIZE)
+ offset = 0;
}
}
return count;
@@ -403,14 +417,24 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct
sk_buff *skb,
unsigned long bytes;
/* Data must not cross a page boundary. */
- BUG_ON(size + offset > PAGE_SIZE);
+ BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
meta = npo->meta + npo->meta_prod - 1;
+ /* Skip unused frames from start of page */
+ page += offset >> PAGE_SHIFT;
+ offset &= ~PAGE_MASK;
+
while (size > 0) {
+ BUG_ON(offset >= PAGE_SIZE);
BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
- if (start_new_rx_buffer(npo->copy_off, size, *head)) {
+ bytes = PAGE_SIZE - offset;
+
+ if (bytes > size)
+ bytes = size;
+
+ if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
/*
* Netfront requires there to be some data in the head
* buffer.
@@ -420,7 +444,6 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct
sk_buff *skb,
meta = get_next_rx_buffer(vif, npo);
}
- bytes = size;
if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
bytes = MAX_BUFFER_OFFSET - npo->copy_off;
@@ -453,6 +476,13 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct
sk_buff *skb,
offset += bytes;
size -= bytes;
+ /* Next frame */
+ if (offset == PAGE_SIZE && size) {
+ BUG_ON(!PageCompound(page));
+ page++;
+ offset = 0;
+ }
+
/* Leave a gap for the GSO descriptor. */
if (*head && skb_shinfo(skb)->gso_size &&
!vif->gso_prefix)
vif->rx.req_cons++;
--
1.7.2.5
Konrad Rzeszutek Wilk
2012-Oct-10 18:53 UTC
Re: [PATCH V2] xen: netback: handle compound page fragments on transmit.
On Wed, Oct 10, 2012 at 02:48:42PM +0100, Ian Campbell wrote:> An SKB paged fragment can consist of a compound page with order > 0. > However the netchannel protocol deals only in PAGE_SIZE frames. > > Handle this in netbk_gop_frag_copy and xen_netbk_count_skb_slots by > iterating over the frames which make up the page. > > Signed-off-by: Ian Campbell <ian.campbell@citrix.com> > Cc: Eric Dumazet <eric.dumazet@gmail.com> > Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>> Cc: Sander Eikelenboom <linux@eikelenboom.it> > --- > v2: Only move to next frame if there is data remaining. > --- > drivers/net/xen-netback/netback.c | 40 ++++++++++++++++++++++++++++++++---- > 1 files changed, 35 insertions(+), 5 deletions(-) > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index 4ebfcf3..f2d6b78 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -335,21 +335,35 @@ unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb) > > for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { > unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]); > + unsigned long offset = skb_shinfo(skb)->frags[i].page_offset; > unsigned long bytes; > + > + offset &= ~PAGE_MASK; > + > while (size > 0) { > + BUG_ON(offset >= PAGE_SIZE); > BUG_ON(copy_off > MAX_BUFFER_OFFSET); > > - if (start_new_rx_buffer(copy_off, size, 0)) { > + bytes = PAGE_SIZE - offset; > + > + if (bytes > size) > + bytes = size; > + > + if (start_new_rx_buffer(copy_off, bytes, 0)) { > count++; > copy_off = 0; > } > > - bytes = size; > if (copy_off + bytes > MAX_BUFFER_OFFSET) > bytes = MAX_BUFFER_OFFSET - copy_off; > > copy_off += bytes; > + > + offset += bytes; > size -= bytes; > + > + if (offset == PAGE_SIZE) > + offset = 0; > } > } > return count; > @@ -403,14 +417,24 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb, > unsigned long bytes; > > /* Data must not cross a page boundary. */ > - BUG_ON(size + offset > PAGE_SIZE); > + BUG_ON(size + offset > PAGE_SIZE<<compound_order(page)); > > meta = npo->meta + npo->meta_prod - 1; > > + /* Skip unused frames from start of page */ > + page += offset >> PAGE_SHIFT; > + offset &= ~PAGE_MASK; > + > while (size > 0) { > + BUG_ON(offset >= PAGE_SIZE); > BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET); > > - if (start_new_rx_buffer(npo->copy_off, size, *head)) { > + bytes = PAGE_SIZE - offset; > + > + if (bytes > size) > + bytes = size; > + > + if (start_new_rx_buffer(npo->copy_off, bytes, *head)) { > /* > * Netfront requires there to be some data in the head > * buffer. > @@ -420,7 +444,6 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb, > meta = get_next_rx_buffer(vif, npo); > } > > - bytes = size; > if (npo->copy_off + bytes > MAX_BUFFER_OFFSET) > bytes = MAX_BUFFER_OFFSET - npo->copy_off; > > @@ -453,6 +476,13 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb, > offset += bytes; > size -= bytes; > > + /* Next frame */ > + if (offset == PAGE_SIZE && size) { > + BUG_ON(!PageCompound(page)); > + page++; > + offset = 0; > + } > + > /* Leave a gap for the GSO descriptor. */ > if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix) > vif->rx.req_cons++; > -- > 1.7.2.5 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel >
David Miller
2012-Oct-11 02:54 UTC
Re: [PATCH V2] xen: netback: handle compound page fragments on transmit.
From: Ian Campbell <ian.campbell@citrix.com> Date: Wed, 10 Oct 2012 14:48:42 +0100> An SKB paged fragment can consist of a compound page with order > 0. > However the netchannel protocol deals only in PAGE_SIZE frames. > > Handle this in netbk_gop_frag_copy and xen_netbk_count_skb_slots by > iterating over the frames which make up the page. > > Signed-off-by: Ian Campbell <ian.campbell@citrix.com>Applied.