diff options
| author | Shirley Ma <mashirle@us.ibm.com> | 2010-01-18 19:15:23 +0530 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2010-02-24 14:22:27 +1030 |
| commit | c021eac4148c16bf53baa0dd14e8ebee6f39dab5 (patch) | |
| tree | 558db2ede74488606614d6e7e277f9914e38fbc1 | |
| parent | 69740c8ba878f58bc3c71f74618fc2cd1da990da (diff) | |
virtio: Add ability to detach unused buffers from vrings
There's currently no way for a virtio driver to ask for unused
buffers, so it has to keep a list itself to reclaim them at shutdown.
This is redundant, since virtio_ring stores that information. So
add a new hook to do this.
Signed-off-by: Shirley Ma <xma@us.ibm.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| -rw-r--r-- | drivers/virtio/virtio_ring.c | 25 | ||||
| -rw-r--r-- | include/linux/virtio.h | 4 |
2 files changed, 29 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 827f7e04261..782b7292a3d 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -351,6 +351,30 @@ static bool vring_enable_cb(struct virtqueue *_vq) return true; } +static void *vring_detach_unused_buf(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + unsigned int i; + void *buf; + + START_USE(vq); + + for (i = 0; i < vq->vring.num; i++) { + if (!vq->data[i]) + continue; + /* detach_buf clears data, so grab it now. */ + buf = vq->data[i]; + detach_buf(vq, i); + END_USE(vq); + return buf; + } + /* That should have freed everything. */ + BUG_ON(vq->num_free != vq->vring.num); + + END_USE(vq); + return NULL; +} + irqreturn_t vring_interrupt(int irq, void *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); @@ -377,6 +401,7 @@ static struct virtqueue_ops vring_vq_ops = { .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, + .detach_unused_buf = vring_detach_unused_buf, }; struct virtqueue *vring_new_virtqueue(unsigned int num, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 057a2e01075..f508c651e53 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -51,6 +51,9 @@ struct virtqueue { * This re-enables callbacks; it returns "false" if there are pending * buffers in the queue, to detect a possible race between the driver * checking for more work, and enabling callbacks. + * @detach_unused_buf: detach first unused buffer + * vq: the struct virtqueue we're talking about. + * Returns NULL or the "data" token handed to add_buf * * Locking rules are straightforward: the driver is responsible for * locking. No two operations may be invoked simultaneously, with the exception @@ -71,6 +74,7 @@ struct virtqueue_ops { void (*disable_cb)(struct virtqueue *vq); bool (*enable_cb)(struct virtqueue *vq); + void *(*detach_unused_buf)(struct virtqueue *vq); }; /** |