From 8704b9e9dbbc61353f6acbb257649ee821d12507 Mon Sep 17 00:00:00 2001 From: Nathan Whitehorn Date: Thu, 12 Mar 2015 17:01:30 +0000 Subject: [PATCH] The H_VIO_SIGNAL hypercall only enables interrupts for future received packets and does not schedule interrupts for any packets currently enqueued. Close two races where enqueued packets may not ever trigger interrupts. The first of these, at adapter initialization time, was especially severe since a rush of enqueued packets could actually fill the receive buffer completely, stalling the interface forever. MFC after: 2 weeks --- sys/powerpc/pseries/phyp_llan.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/sys/powerpc/pseries/phyp_llan.c b/sys/powerpc/pseries/phyp_llan.c index 0b25f398fb8..26dbcc07a21 100644 --- a/sys/powerpc/pseries/phyp_llan.c +++ b/sys/powerpc/pseries/phyp_llan.c @@ -273,6 +273,9 @@ llan_init(void *xsc) sc->ifp->if_drv_flags &= ~IFF_DRV_OACTIVE; mtx_unlock(&sc->io_lock); + + /* Check for pending receives scheduled before interrupt enable */ + llan_intr(sc); } static int @@ -335,6 +338,7 @@ llan_intr(void *xsc) struct mbuf *m; mtx_lock(&sc->io_lock); +restart: phyp_hcall(H_VIO_SIGNAL, sc->unit, 0); while ((sc->rx_buf[sc->rx_dma_slot].control >> 7) == sc->rx_valid_val) { @@ -369,6 +373,15 @@ llan_intr(void *xsc) } phyp_hcall(H_VIO_SIGNAL, sc->unit, 1); + + /* + * H_VIO_SIGNAL enables interrupts for future packets only. + * Make sure none were queued between the end of the loop and the + * enable interrupts call. + */ + if ((sc->rx_buf[sc->rx_dma_slot].control >> 7) == sc->rx_valid_val) + goto restart; + mtx_unlock(&sc->io_lock); }