This series is to permit MTU change while the interface is running.
Major rework are needed to permit to allocate a new dma conf based on
the new MTU before applying it. This is to make sure there is enough
space to allocate all the DMA queue before releasing the stmmac driver.

This was tested with a simple way to stress the network while the
interface is running.

2 ssh connection to the device:
- One generating simple traffic with while true; do free; done
- The other making the mtu change with a delay of 1 second

The connection is correctly stopped and recovered after the MTU is changed.

The first 2 patch of this series are minor fixup that fix problems presented
while testing this. One fix a problem when we renable a queue while we are
generating a new dma conf. The other is a corner case that was notice while
stressing the driver and turning down the interface while there was some
traffic.

(this is a follow-up of a simpler patch that wanted to add the same feature.
It was suggested to first try to check if it was possible to apply the new
configuration. Posting as RFC as it does major rework for the new concept of
DMA conf)

v2:
- Put it out of RFC

Christian Marangi (5):
  net: ethernet: stmicro: stmmac: move queue reset to dedicated
    functions
  net: ethernet: stmicro: stmmac: first disable all queues in release
  net: ethernet: stmicro: stmmac: move dma conf to dedicated struct
  net: ethernet: stmicro: stmmac: generate stmmac dma conf before open
  net: ethernet: stmicro: stmmac: permit MTU change with interface up

 .../net/ethernet/stmicro/stmmac/chain_mode.c  |   6 +-
 .../net/ethernet/stmicro/stmmac/ring_mode.c   |   4 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac.h  |  21 +-
 .../ethernet/stmicro/stmmac/stmmac_ethtool.c  |   4 +-
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 722 +++++++++++-------
 5 files changed, 450 insertions(+), 307 deletions(-)

-- 
2.36.1