diff options
author | mav <mav@FreeBSD.org> | 2015-05-06 18:04:31 +0000 |
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committer | mav <mav@FreeBSD.org> | 2015-05-06 18:04:31 +0000 |
commit | eb1da255356b44909401335c2e19dd2b33164b33 (patch) | |
tree | 814ffd5f30643fdb220fcd2623554a5205c585bd /usr.sbin/bhyve | |
parent | e9414456bd5902cb842303fb7a425b09e746b4e5 (diff) | |
download | FreeBSD-src-eb1da255356b44909401335c2e19dd2b33164b33.zip FreeBSD-src-eb1da255356b44909401335c2e19dd2b33164b33.tar.gz |
Add memory barrier to r281764.
While race at this point may cause only a single packet delay and so was
not really reproduced, it is better to not have it at all.
MFC after: 1 week
Diffstat (limited to 'usr.sbin/bhyve')
-rw-r--r-- | usr.sbin/bhyve/pci_virtio_net.c | 25 |
1 files changed, 11 insertions, 14 deletions
diff --git a/usr.sbin/bhyve/pci_virtio_net.c b/usr.sbin/bhyve/pci_virtio_net.c index 7227488..1a029d5 100644 --- a/usr.sbin/bhyve/pci_virtio_net.c +++ b/usr.sbin/bhyve/pci_virtio_net.c @@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$"); #include <sys/select.h> #include <sys/uio.h> #include <sys/ioctl.h> +#include <machine/atomic.h> #include <net/ethernet.h> #include <errno.h> @@ -453,7 +454,7 @@ pci_vtnet_tx_thread(void *param) { struct pci_vtnet_softc *sc = param; struct vqueue_info *vq; - int have_work, error; + int error; vq = &sc->vsc_queues[VTNET_TXQ]; @@ -467,20 +468,16 @@ pci_vtnet_tx_thread(void *param) for (;;) { /* note - tx mutex is locked here */ - do { + while (sc->resetting || !vq_has_descs(vq)) { vq->vq_used->vu_flags &= ~VRING_USED_F_NO_NOTIFY; - if (sc->resetting) - have_work = 0; - else - have_work = vq_has_descs(vq); - - if (!have_work) { - sc->tx_in_progress = 0; - error = pthread_cond_wait(&sc->tx_cond, - &sc->tx_mtx); - assert(error == 0); - } - } while (!have_work); + mb(); + if (!sc->resetting && vq_has_descs(vq)) + break; + + sc->tx_in_progress = 0; + error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx); + assert(error == 0); + } vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY; sc->tx_in_progress = 1; pthread_mutex_unlock(&sc->tx_mtx); |