[dpdk-dev] [PATCH] net/enic: revert support for mbuf fast free offload

[Thomas Monjalon]

26/07/2018 04:30, John Daley:
> From: Hyong Youb Kim <hyonkim at cisco.com>
> 
> This reverts the patch that enabled mbuf fast free.
> 
> There are two main reasons.
> 
> First, enic_fast_free_wq_bufs is broken. When
> DEV_TX_OFFLOAD_MBUF_FAST_FREE is enabled, the driver calls this
> function to free transmitted mbufs. This function currently does not
> reset next and nb_segs. This is simply wrong as the fast-free flag
> does not imply anything about next and nb_segs.
> 
> We could fix enic_fast_free_wq_bufs by making it to call
> rte_pktmbuf_prefree_seg to reset the required fields. But, it negates
> most of cycle saving.
> 
> Second, there are customer applications that blindly enable all Tx
> offloads supported by the device. Some of these applications do not
> satisfy the requirements of mbuf fast free (i.e. a single pool per
> queue and refcnt = 1), and end up crashing or behaving badly.
> 
> Fixes: bcaa54c1a148 ("net/enic: support mbuf fast free offload")
> 
> Signed-off-by: Hyong Youb Kim <hyonkim at cisco.com>
> Reviewed-by: John Daley <johndale at cisco.com>

Applied