Date: Thu, 12 Mar 2015 17:01:30 +0000 (UTC) From: Nathan Whitehorn <nwhitehorn@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r279928 - head/sys/powerpc/pseries Message-ID: <201503121701.t2CH1UVT004090@svn.freebsd.org>
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Author: nwhitehorn Date: Thu Mar 12 17:01:30 2015 New Revision: 279928 URL: https://svnweb.freebsd.org/changeset/base/279928 Log: 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 Modified: head/sys/powerpc/pseries/phyp_llan.c Modified: head/sys/powerpc/pseries/phyp_llan.c ============================================================================== --- head/sys/powerpc/pseries/phyp_llan.c Thu Mar 12 16:19:18 2015 (r279927) +++ head/sys/powerpc/pseries/phyp_llan.c Thu Mar 12 17:01:30 2015 (r279928) @@ -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); }
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