diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2010-09-16 14:43:08 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-09-26 17:18:20 -0700 |
| commit | ba4de7fd43bb21be634a39b0de274cfb9b19fd83 (patch) | |
| tree | 85f45c50a7a7c9fc97ce04bb630f4c7cc128b46f | |
| parent | d4f5d4c1a4f45e69deb3bcf727e511b0637a72d1 (diff) | |
virtio: console: Fix poll blocking even though there is data to read
commit 6df7aadcd9290807c464675098b5dd2dc9da5075 upstream.
I found this while working on a Linux agent for spice, the symptom I was
seeing was select blocking on the spice vdagent virtio serial port even
though there were messages queued up there.
virtio_console's port_fops_poll checks port->inbuf != NULL to determine
if read won't block. However if an application reads enough bytes from
inbuf through port_fops_read, to empty the current port->inbuf,
port->inbuf will be NULL even though there may be buffers left in the
virtqueue.
This causes poll() to block even though there is data to be read,
this patch fixes this by using will_read_block(port) instead of the
port->inbuf != NULL check.
Signed-off-By: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/char/virtio_console.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 56ffd0d93e2..c810481a5bc 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -646,7 +646,7 @@ static unsigned int port_fops_poll(struct file *filp, poll_table *wait) poll_wait(filp, &port->waitqueue, wait); ret = 0; - if (port->inbuf) + if (!will_read_block(port)) ret |= POLLIN | POLLRDNORM; if (!will_write_block(port)) ret |= POLLOUT; |