From f0c3192ceee3c16154e70dfb373f66ed86c6fea9 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Fri, 2 Jun 2017 17:54:33 +0300 Subject: [PATCH] virtio_net: lower limit on buffer size commit d85b758f72b0 ("virtio_net: fix support for small rings") was supposed to increase the buffer size for small rings but had an unintentional side effect of decreasing it for large rings. This seems to break some setups - it's not yet clear why, but increasing buffer size back to what it was before helps. Fixes: d85b758f72b0 ("virtio_net: fix support for small rings") Reported-by: Mikulas Patocka Reported-by: "J. Bruce Fields" Tested-by: Mikulas Patocka Tested-by: "J. Bruce Fields" Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 3e9246cc49c3..a871f45ecc79 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -869,7 +869,7 @@ static unsigned int get_mergeable_buf_len(struct receive_queue *rq, unsigned int len; len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len), - rq->min_buf_len - hdr_len, PAGE_SIZE - hdr_len); + rq->min_buf_len, PAGE_SIZE - hdr_len); return ALIGN(len, L1_CACHE_BYTES); } @@ -2144,7 +2144,8 @@ static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqu unsigned int buf_len = hdr_len + ETH_HLEN + VLAN_HLEN + packet_len; unsigned int min_buf_len = DIV_ROUND_UP(buf_len, rq_size); - return max(min_buf_len, hdr_len); + return max(max(min_buf_len, hdr_len) - hdr_len, + (unsigned int)GOOD_PACKET_LEN); } static int virtnet_find_vqs(struct virtnet_info *vi) -- 2.20.1