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| author | Rusty Russell <rusty@rustcorp.com.au> | 2010-04-08 09:46:16 -0600 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2010-04-08 09:46:17 +0930 |
| commit | 9ff4cfab82d27e9fda72315f911bbaa9516e04bc (patch) | |
| tree | a3c16833f8d9c0eb3d4194f4fd11c98e3899ffb4 /drivers/char/virtio_console.c | |
| parent | 162a689a13ed61c0752726edb75427b2cd4186c1 (diff) | |
| download | lwn-9ff4cfab82d27e9fda72315f911bbaa9516e04bc.tar.gz lwn-9ff4cfab82d27e9fda72315f911bbaa9516e04bc.zip | |
virtio: console makes incorrect assumption about virtio API
The get_buf() API sets the second arg to the number of bytes *written*
by the other side; in this case it should be zero as these are output buffers.
lguest gets this right (obviously kvm's console doesn't), resulting in
continual buildup of console writes.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Amit Shah <amit.shah@redhat.com>
Diffstat (limited to 'drivers/char/virtio_console.c')
| -rw-r--r-- | drivers/char/virtio_console.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 48306bc733f7..86e9011325dc 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -416,20 +416,16 @@ static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count) out_vq->vq_ops->kick(out_vq); if (ret < 0) { - len = 0; + in_count = 0; goto fail; } - /* - * Wait till the host acknowledges it pushed out the data we - * sent. Also ensure we return to userspace the number of - * bytes that were successfully consumed by the host. - */ + /* Wait till the host acknowledges it pushed out the data we sent. */ while (!out_vq->vq_ops->get_buf(out_vq, &len)) cpu_relax(); fail: /* We're expected to return the amount of data we wrote */ - return len; + return in_count; } /* |