On Tue, 21 Mar 2017, Juergen Gross wrote: > On 20/03/17 18:59, Stefano Stabellini wrote: > > Implement struct p9_trans_module create and close functions by looking > > at the available Xen 9pfs frontend-backend connections. We don't expect > > many frontend-backend connections, thus walking a list is OK. > > > > Send requests to the backend by copying each request to one of the > > available rings (each frontend-backend connection comes with multiple > > rings). Handle the ring and notifications following the 9pfs > > specification. If there are not enough free bytes on the ring for the > > request, wait on the wait_queue: the backend will send a notification > > after consuming more requests. > > > > Signed-off-by: Stefano Stabellini <stef...@aporeto.com> > > Reviewed-by: Boris Ostrovsky <boris.ostrov...@oracle.com> > > CC: gr...@kaod.org > > CC: jgr...@suse.com > > CC: Eric Van Hensbergen <eri...@gmail.com> > > CC: Ron Minnich <rminn...@sandia.gov> > > CC: Latchesar Ionkov <lu...@ionkov.net> > > CC: v9fs-develo...@lists.sourceforge.net > > --- > > net/9p/trans_xen.c | 91 > > ++++++++++++++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 89 insertions(+), 2 deletions(-) > > > > diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c > > index 5279ae0..e51edac 100644 > > --- a/net/9p/trans_xen.c > > +++ b/net/9p/trans_xen.c > > > +static int p9_xen_write_todo(struct xen_9pfs_dataring *ring, RING_IDX size) > > +{ > > + RING_IDX cons, prod; > > + > > + cons = ring->intf->out_cons; > > + prod = ring->intf->out_prod; > > + virt_mb(); > > + > > + if (XEN_9PFS_RING_SIZE - xen_9pfs_queued(prod, cons, > > + XEN_9PFS_RING_SIZE) >= size) > > + return 1; > > + else > > + return 0; > > } > > Make return type of function bool and use: > > return XEN_9PFS_RING_SIZE - xen_9pfs_queued(prod, cons, > XEN_9PFS_RING_SIZE) >= size; > > and further below ...
Good idea > > > > static int p9_xen_request(struct p9_client *client, struct p9_req_t > > *p9_req) > > { > > + struct xen_9pfs_front_priv *priv = NULL; > > + RING_IDX cons, prod, masked_cons, masked_prod; > > + unsigned long flags; > > + u32 size = p9_req->tc->size; > > + struct xen_9pfs_dataring *ring; > > + int num; > > + > > + read_lock(&xen_9pfs_lock); > > + list_for_each_entry(priv, &xen_9pfs_devs, list) { > > + if (priv->client == client) > > + break; > > + } > > + read_unlock(&xen_9pfs_lock); > > + if (!priv || priv->client != client) > > + return -EINVAL; > > + > > + num = p9_req->tc->tag % priv->num_rings; > > + ring = &priv->rings[num]; > > + > > +again: > > + while (wait_event_interruptible(ring->wq, > > + p9_xen_write_todo(ring, size) > 0) != 0) > > ... you can omit the "> 0". I'll do that _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel