net: sfc: fix using uninitialized xdp tx_queue
In some cases, xdp tx_queue can get used before initialization. 1. interface up/down 2. ring buffer size change When CPU cores are lower than maximum number of channels of sfc driver, it creates new channels only for XDP. When an interface is up or ring buffer size is changed, all channels are initialized. But xdp channels are always initialized later. So, the below scenario is possible. Packets are received to rx queue of normal channels and it is acted XDP_TX and tx_queue of xdp channels get used. But these tx_queues are not initialized yet. If so, TX DMA or queue error occurs. In order to avoid this problem. 1. initializes xdp tx_queues earlier than other rx_queue in efx_start_channels(). 2. checks whether tx_queue is initialized or not in efx_xdp_tx_buffers(). Splat looks like: sfc 0000:08:00.1 enp8s0f1np1: TX queue 10 spurious TX completion id 250 sfc 0000:08:00.1 enp8s0f1np1: resetting (RECOVER_OR_ALL) sfc 0000:08:00.1 enp8s0f1np1: MC command 0x80 inlen 100 failed rc=-22 (raw=22) arg=789 sfc 0000:08:00.1 enp8s0f1np1: has been disabled Fixes: f28100cb ("sfc: fix lack of XDP TX queues - error XDP TX failed (-22)") Acked-by:Martin Habets <habetsm.xilinx@gmail.com> Signed-off-by: