Zoltan Kiss 9ab9831b4c xen-netback: Fix Rx stall due to race condition ... The recent patch to fix receive side flow control (11b57f9025: xen-netback: stop vif thread spinning if frontend is unresponsive) solved the spinning thread problem, however caused an another one. The receive side can stall, if: - [THREAD] xenvif_rx_action sets rx_queue_stopped to true - [INTERRUPT] interrupt happens, and sets rx_event to true - [THREAD] then xenvif_kthread sets rx_event to false - [THREAD] rx_work_todo doesn't return true anymore Also, if interrupt sent but there is still no room in the ring, it take quite a long time until xenvif_rx_action realize it. This patch ditch that two variable, and rework rx_work_todo. If the thread finds it can't fit more skb's into the ring, it saves the last slot estimation into rx_last_skb_slots, otherwise it's kept as 0. Then rx_work_todo will check if: - there is something to send to the ring (like before) - there is space for the topmost packet in the queue I think that's more natural and optimal thing to test than two bool which are set somewhere else. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2014-02-05 16:24:08 -08:00
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common.h	xen-netback: Fix Rx stall due to race condition	2014-02-05 16:24:08 -08:00
interface.c	xen-netback: Fix Rx stall due to race condition	2014-02-05 16:24:08 -08:00
Makefile	xen network backend driver	2011-03-15 19:38:03 -07:00
netback.c	xen-netback: Fix Rx stall due to race condition	2014-02-05 16:24:08 -08:00
xenbus.c	drivers/net/*: Fix FSF address in file headers	2013-12-06 12:37:55 -05:00