[dpdk-dev,0/5] virtio/mbuf: fix virtio tso with shared mbufs
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This patchset fixes the transmission of cloned mbufs when using
virtio + TSO. The problem is we need to fix the L4 checksum in the
packet, but it should be considered as read-only, as pointed-out
by Stephen here:
http://dpdk.org/ml/archives/dev/2016-October/048873.html
Unfortunatly the patchset is quite big, but I did not manage to
find a shorter solution. The first patches add some mbuf helpers
that are used in virtio in the last patch.
This last patch adds a zone for each tx ring entry where headers
can be copied, patched, and referenced by virtio descriptors in
case the mbuf is read-only. If its not the case, the mbuf is
modified as before.
I tested with the same test plan than the one described in
http://dpdk.org/ml/archives/dev/2016-October/048092.html
(only the TSO test case).
I also replayed the test with the following patches to validate
the code path for:
- segmented packets (it forces a local copy in virtio_tso_fix_cksum)
Olivier Matz (5):
mbuf: remove const attribute in mbuf read function
mbuf: new helper to check if a mbuf is shared
mbuf: new helper to write data in a mbuf chain
mbuf: new helper to copy data from a mbuf
net/virtio: fix Tso when mbuf is shared
app/test/test_mbuf.c | 62 +++++++++++++-
drivers/net/virtio/virtio_rxtx.c | 119 ++++++++++++++++++--------
drivers/net/virtio/virtqueue.h | 2 +
lib/librte_mbuf/rte_mbuf.c | 46 +++++++++-
lib/librte_mbuf/rte_mbuf.h | 157 ++++++++++++++++++++++++++++++++++-
lib/librte_mbuf/rte_mbuf_version.map | 6 ++
6 files changed, 347 insertions(+), 45 deletions(-)
@@ -279,7 +279,7 @@ void *__rte_pktmbuf_read(const struct rte_mbuf *m, uint32_t off,
seg = seg->next;
}
- if (off + len <= rte_pktmbuf_data_len(seg))
+ if (0 && off + len <= rte_pktmbuf_data_len(seg))
return rte_pktmbuf_mtod_offset(seg, char *, off);
/* rare case: header is split among several segments */
@@ -1671,7 +1671,7 @@ void *__rte_pktmbuf_read(const struct rte_mbuf *m, uint32_t off,
static inline void *rte_pktmbuf_read(const struct rte_mbuf *m,
uint32_t off, uint32_t len, void *buf)
{
- if (likely(off + len <= rte_pktmbuf_data_len(m)))
+ if (likely(0 && off + len <= rte_pktmbuf_data_len(m)))
return rte_pktmbuf_mtod_offset(m, char *, off);
else
return __rte_pktmbuf_read(m, off, len, buf);
- and for shared mbuf (force to use the buffer in virtio tx ring)
@@ -225,7 +225,7 @@ virtio_tso_fix_cksum(struct rte_mbuf *m, char *hdr, size_t hdr_sz)
int shared = 0;
/* mbuf is write-only, we need to copy the headers in a linear buffer */
- if (unlikely(rte_pktmbuf_data_is_shared(m, 0, hdrlen))) {
+ if (unlikely(1 || rte_pktmbuf_data_is_shared(m, 0, hdrlen))) {
shared = 1;
/* network headers are too big, there's nothing we can do */