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| author | Rusty Russell <rusty@rustcorp.com.au> | 2008-05-31 00:09:46 +0400 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2008-05-30 09:09:46 +0400 |
| commit | 20887611523e749d99cc7d64ff6c97d27529fbae (patch) | |
| tree | a0b74c524c23762133b8b3de8235753760b13071 /Documentation/lguest | |
| parent | b4f68be6c5d507afdcd74f5be3df0b1209cda503 (diff) | |
| download | linux-20887611523e749d99cc7d64ff6c97d27529fbae.tar.xz | |
lguest: notify on empty
This is the lguest implementation of the VIRTIO_F_NOTIFY_ON_EMPTY feature.
It is currently only published for network devices, but it is turned on for
everyone.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'Documentation/lguest')
| -rw-r--r-- | Documentation/lguest/lguest.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 3be8ab2a886a..82fafe0429fe 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -157,6 +157,9 @@ struct virtqueue /* The routine to call when the Guest pings us. */ void (*handle_output)(int fd, struct virtqueue *me); + + /* Outstanding buffers */ + unsigned int inflight; }; /* Remember the arguments to the program so we can "reboot" */ @@ -702,6 +705,7 @@ static unsigned get_vq_desc(struct virtqueue *vq, errx(1, "Looped descriptor"); } while ((i = next_desc(vq, i)) != vq->vring.num); + vq->inflight++; return head; } @@ -719,6 +723,7 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len) /* Make sure buffer is written before we update index. */ wmb(); vq->vring.used->idx++; + vq->inflight--; } /* This actually sends the interrupt for this virtqueue */ @@ -726,8 +731,9 @@ static void trigger_irq(int fd, struct virtqueue *vq) { unsigned long buf[] = { LHREQ_IRQ, vq->config.irq }; - /* If they don't want an interrupt, don't send one. */ - if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) + /* If they don't want an interrupt, don't send one, unless empty. */ + if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) + && vq->inflight) return; /* Send the Guest an interrupt tell them we used something up. */ @@ -1107,6 +1113,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs, vq->next = NULL; vq->last_avail_idx = 0; vq->dev = dev; + vq->inflight = 0; /* Initialize the configuration. */ vq->config.num = num_descs; @@ -1368,6 +1375,7 @@ static void setup_tun_net(const char *arg) /* Tell Guest what MAC address to use. */ add_feature(dev, VIRTIO_NET_F_MAC); + add_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY); set_config(dev, sizeof(conf), &conf); /* We don't need the socket any more; setup is done. */ |