On Thu, Nov 17, 2022 at 01:21:21AM +0200, Vladimir Oltean wrote: > Hi, > > On Mon, Nov 14, 2022 at 04:03:22PM -0800, Tony Nguyen wrote: > > This series contains updates to i40e driver only. > > > > Sylwester removes attempted allocation of Rx buffers when AF_XDP is in Tx > > only mode. > > > > Bartosz adds helper to calculate Rx buffer length so that it can be > > used when interface is down; before value has been set in struct. > > > > The following are changes since commit ed1fe1bebe18884b11e5536b5ac42e3a48960835: > > net: dsa: make dsa_master_ioctl() see through port_hwtstamp_get() shims > > and are available in the git repository at: > > git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue 40GbE > > > > Bartosz Staszewski (1): > > i40e: fix xdp_redirect logs error message when testing with MTU=1500 > > > > Sylwester Dziedziuch (1): > > i40e: Fix failure message when XDP is configured in TX only mode > > > > drivers/net/ethernet/intel/i40e/i40e_main.c | 48 +++++++++++++++------ > > 1 file changed, 34 insertions(+), 14 deletions(-) > > > > -- > > 2.35.1 > > > > Sorry to interject, but there might be a potential bug I noticed a while > ago in the i40e driver, and I didn't find the occasion to bring it up, > but remembered just now. > > Is it correct for i40e_run_xdp_zc() to call i40e_xmit_xdp_tx_ring() on > the XDP_TX action? If I'm reading the code correctly, this will map the > buffer to DMA before sending it. But since this is a zero-copy RX buffer, > it has already been mapped to DMA in i40e_xsk_pool_enable(). Hey Vladimir, have a look at xdp_convert_zc_to_xdp_frame() in net/core/xdp.c. For XDP_TX on ZC Rx side we basically create new xdp_frame backed by new page and copy the contents we had in ZC buffer. Then we give back the ZC buffer to XSK buff pool and new xdp_frame has to be DMA mapped to HW. > > Since I don't have the hardware, I can't be 100% sure if I'm following > the code correctly. However if I compare with i40e_xmit_zc(), the latter > does not map buffers to DMA, so I think neither should the former.
