similar to: [PATCH 1/4] virtio_net: Fix skb->csum_start computation

On Thursday 01 May 2008 00:31:46 Mark McLoughlin wrote: > virtio_net currently only frees old transmit skbs just > before queueing new ones. If the queue is full, it then > enables interrupts and waits for notification that more > work has been performed. Hi Mark, This patch is fine, but it's better to do it from skb_xmit_done(). Of course, this is usually called from an

On Thursday 01 May 2008 00:31:46 Mark McLoughlin wrote: > virtio_net currently only frees old transmit skbs just > before queueing new ones. If the queue is full, it then > enables interrupts and waits for notification that more > work has been performed. Hi Mark, This patch is fine, but it's better to do it from skb_xmit_done(). Of course, this is usually called from an

If we fail to transmit a packet, we assume the queue is full and put the skb into last_xmit_skb. However, if more space frees up before we xmit it, we loop, and the result can be transmitting the same skb twice. Fix is simple: set skb to NULL if we've used it in some way, and check before sending. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- drivers/net/virtio_net.c |

If we fail to transmit a packet, we assume the queue is full and put the skb into last_xmit_skb. However, if more space frees up before we xmit it, we loop, and the result can be transmitting the same skb twice. Fix is simple: set skb to NULL if we've used it in some way, and check before sending. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- drivers/net/virtio_net.c |

The virtio_net driver is complicated by the two methods of freeing old xmit buffers (in addition to freeing old ones at the start of the xmit path). The original code used a 1/10 second timer attached to xmit_free(), reset on every xmit. Before we orphaned skbs on xmit, the transmitting userspace could block with a full socket until the timer fired, the skb destructor was called, and they were

The virtio_net driver is complicated by the two methods of freeing old xmit buffers (in addition to freeing old ones at the start of the xmit path). The original code used a 1/10 second timer attached to xmit_free(), reset on every xmit. Before we orphaned skbs on xmit, the transmitting userspace could block with a full socket until the timer fired, the skb destructor was called, and they were

From: Mark McLoughlin <markmc at redhat.com> hdr->csum_start is the offset from the start of the ethernet header to the transport layer checksum field. skb->csum_start is the offset from skb->head. skb_partial_csum_set() assumes that skb->data points to the ethernet header - i.e. it computes skb->csum_start by adding the headroom to hdr->csum_start. Since

From: Mark McLoughlin <markmc at redhat.com> hdr->csum_start is the offset from the start of the ethernet header to the transport layer checksum field. skb->csum_start is the offset from skb->head. skb_partial_csum_set() assumes that skb->data points to the ethernet header - i.e. it computes skb->csum_start by adding the headroom to hdr->csum_start. Since

On Tue, May 27, 2008 at 12:20:47PM +0100, Mark McLoughlin wrote: > hdr->csum_start is the offset from the start of the ethernet > header to the transport layer checksum field. skb->csum_start > is the offset from skb->head. > > skb_partial_csum_set() assumes that skb->data points to the > ethernet header - i.e. it computes skb->csum_start by adding > the

On Tue, May 27, 2008 at 12:20:47PM +0100, Mark McLoughlin wrote: > hdr->csum_start is the offset from the start of the ethernet > header to the transport layer checksum field. skb->csum_start > is the offset from skb->head. > > skb_partial_csum_set() assumes that skb->data points to the > ethernet header - i.e. it computes skb->csum_start by adding > the

This effectively reverts 99ffc696d10b28580fe93441d627cf290ac4484c "virtio: wean net driver off NETDEV_TX_BUSY". The complexity of queuing an skb (setting a tasklet to re-xmit) is questionable, especially once we get rid of the other reason for the tasklet in the next patch. If the skb won't fit in the tx queue, just return NETDEV_TX_BUSY. It might be frowned upon, but it's

This effectively reverts 99ffc696d10b28580fe93441d627cf290ac4484c "virtio: wean net driver off NETDEV_TX_BUSY". The complexity of queuing an skb (setting a tasklet to re-xmit) is questionable, especially once we get rid of the other reason for the tasklet in the next patch. If the skb won't fit in the tx queue, just return NETDEV_TX_BUSY. It might be frowned upon, but it's

2.6.25-stable review patch. If anyone has any objections, please let us know. ------------------ From: Mark McLoughlin <markmc at redhat.com> commit 23cde76d801246a702e7a84c3fe3d655b35c89a1 upstream. hdr->csum_start is the offset from the start of the ethernet header to the transport layer checksum field. skb->csum_start is the offset from skb->head. skb_partial_csum_set()

skb is only NULL the first time around: it's more correct to test for being under-budget. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> diff -r 2a94425ac7d5 drivers/net/virtio_net.c --- a/drivers/net/virtio_net.c Thu Nov 15 13:47:28 2007 +1100 +++ b/drivers/net/virtio_net.c Thu Nov 15 23:10:44 2007 +1100 @@ -198,8 +198,8 @@ again: if (vi->num < vi->max / 2)

skb is only NULL the first time around: it's more correct to test for being under-budget. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> diff -r 2a94425ac7d5 drivers/net/virtio_net.c --- a/drivers/net/virtio_net.c Thu Nov 15 13:47:28 2007 +1100 +++ b/drivers/net/virtio_net.c Thu Nov 15 23:10:44 2007 +1100 @@ -198,8 +198,8 @@ again: if (vi->num < vi->max / 2)

This API change means that virtio_net can tell how much capacity remains for buffers. It's necessarily fuzzy, since VIRTIO_RING_F_INDIRECT_DESC means we can fit any number of descriptors in one, *if* we can kmalloc. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> Cc: Dinesh Subhraveti <dineshs at us.ibm.com> --- drivers/block/virtio_blk.c | 2 +-

This API change means that virtio_net can tell how much capacity remains for buffers. It's necessarily fuzzy, since VIRTIO_RING_F_INDIRECT_DESC means we can fit any number of descriptors in one, *if* we can kmalloc. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> Cc: Dinesh Subhraveti <dineshs at us.ibm.com> --- drivers/block/virtio_blk.c | 2 +-

With 2.6.31-rc5 in a KVM guest using dm and virtio_blk, we see the following errors: end_request: I/O error, dev vda, sector 0 end_request: I/O error, dev vda, sector 0 The errors go away if dm stops submitting empty barriers, by reverting: commit 52b1fd5a27c625c78373e024bf570af3c9d44a79 Author: Mikulas Patocka <mpatocka at redhat.com> dm: send empty barriers to targets in

With 2.6.31-rc5 in a KVM guest using dm and virtio_blk, we see the following errors: end_request: I/O error, dev vda, sector 0 end_request: I/O error, dev vda, sector 0 The errors go away if dm stops submitting empty barriers, by reverting: commit 52b1fd5a27c625c78373e024bf570af3c9d44a79 Author: Mikulas Patocka <mpatocka at redhat.com> dm: send empty barriers to targets in

(Moved from kvm at vger to virtualization at linux-foundation, changed subject, cleaned up cc list) On Wed, 2008-12-10 at 13:02 +0100, Kay Sievers wrote: > On Wed, Dec 10, 2008 at 10:49, Mark McLoughlin <markmc at redhat.com> wrote: > > On Tue, 2008-12-09 at 19:16 +0100, Kay Sievers wrote: > >> On Tue, Dec 9, 2008 at 17:41, Mark McLoughlin <markmc at redhat.com>