[dpdk-stable] [PATCH v2] net/ixgbe: fix RxQ/TxQ release

[Wang, Haiyue]

> -----Original Message-----
> From: Julien Meunier <julien.meunier at nokia.com>
> Sent: Tuesday, September 28, 2021 16:13
> To: dev at dpdk.org
> Cc: stable at dpdk.org; Richardson, Bruce <bruce.richardson at intel.com>; Wang, Haiyue
> <haiyue.wang at intel.com>
> Subject: [PATCH v2] net/ixgbe: fix RxQ/TxQ release
> 
> On the vector implementation, during the tear-down, the mbufs not
> drained in the RxQ and TxQ are freed based on an algorithm which
> supposed that the number of descriptors is a power of 2 (max_desc).
> Based on this hypothesis, this algorithm uses a bitmask in order to
> detect an index overflow during the iteration, and to restart the loop
> from 0.
> 
> However, there is no such power of 2 requirement in the ixgbe for the
> number of descriptors in the RxQ / TxQ. The only requirement is to have
> a number correctly aligned.
> 
> If a user requested to configure a number of descriptors which is not a
> power of 2, as a consequence, during the tear-down, it was possible to
> be in an infinite loop, and to never reach the exit loop condition.
> 
> By removing the bitmask and changing the loop method, we can avoid this
> issue, and allow the user to configure a RxQ / TxQ which is not a power
> of 2.
> 
> Fixes: c95584dc2b18 ("ixgbe: new vectorized functions for Rx/Tx")
> Cc: bruce.richardson at intel.com
> Cc: stable at dpdk.org
> 
> Signed-off-by: Julien Meunier <julien.meunier at nokia.com>
> ---
>  drivers/net/ixgbe/ixgbe_rxtx_vec_common.h | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 

Acked-by: Haiyue Wang <haiyue.wang at intel.com>

> --
> 2.17.1