diff options
| -rw-r--r-- | Documentation/lguest/lguest.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 20f8253881b3..64110797044a 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -769,6 +769,16 @@ static void net_output(struct virtqueue *vq) add_used(vq, head, 0); } +/* Will reading from this file descriptor block? */ +static bool will_block(int fd) +{ + fd_set fdset; + struct timeval zero = { 0, 0 }; + FD_ZERO(&fdset); + FD_SET(fd, &fdset); + return select(fd+1, &fdset, NULL, NULL, &zero) != 1; +} + /* This is where we handle packets coming in from the tun device to our * Guest. */ static void net_input(struct virtqueue *vq) @@ -781,10 +791,15 @@ static void net_input(struct virtqueue *vq) head = wait_for_vq_desc(vq, iov, &out, &in); if (out) errx(1, "Output buffers in net input queue?"); + + /* Deliver interrupt now, since we're about to sleep. */ + if (vq->pending_used && will_block(net_info->tunfd)) + trigger_irq(vq); + len = readv(net_info->tunfd, iov, in); if (len <= 0) err(1, "Failed to read from tun."); - add_used_and_trigger(vq, head, len); + add_used(vq, head, len); } /* This is the helper to create threads. */ |