| Message ID | 1490032788-23471-5-git-send-email-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <stefano@aporeto.com> > Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> > CC: groug@kaod.org > CC: jgross@suse.com > CC: Eric Van Hensbergen <ericvh@gmail.com> > CC: Ron Minnich <rminnich@sandia.gov> > CC: Latchesar Ionkov <lucho@ionkov.net> > CC: v9fs-developer@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 ... > > 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". Juergen
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 <stefano@aporeto.com> > > Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> > > CC: groug@kaod.org > > CC: jgross@suse.com > > CC: Eric Van Hensbergen <ericvh@gmail.com> > > CC: Ron Minnich <rminnich@sandia.gov> > > CC: Latchesar Ionkov <lucho@ionkov.net> > > CC: v9fs-developer@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
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 @@ -77,22 +77,109 @@ struct xen_9pfs_front_priv { static LIST_HEAD(xen_9pfs_devs); static DEFINE_RWLOCK(xen_9pfs_lock); +/* We don't currently allow canceling of requests */ static int p9_xen_cancel(struct p9_client *client, struct p9_req_t *req) { - return 0; + return 1; } static int p9_xen_create(struct p9_client *client, const char *addr, char *args) { - return 0; + struct xen_9pfs_front_priv *priv; + + read_lock(&xen_9pfs_lock); + list_for_each_entry(priv, &xen_9pfs_devs, list) { + if (!strcmp(priv->tag, addr)) { + priv->client = client; + read_unlock(&xen_9pfs_lock); + return 0; + } + } + read_unlock(&xen_9pfs_lock); + return -EINVAL; } static void p9_xen_close(struct p9_client *client) { + struct xen_9pfs_front_priv *priv; + + read_lock(&xen_9pfs_lock); + list_for_each_entry(priv, &xen_9pfs_devs, list) { + if (priv->client == client) { + priv->client = NULL; + read_unlock(&xen_9pfs_lock); + return; + } + } + read_unlock(&xen_9pfs_lock); +} + +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; } 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) + ; + + spin_lock_irqsave(&ring->lock, flags); + 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) { + spin_unlock_irqrestore(&ring->lock, flags); + goto again; + } + + masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE); + masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE); + + xen_9pfs_write_packet(ring->data.out, + &masked_prod, masked_cons, + XEN_9PFS_RING_SIZE, p9_req->tc->sdata, size); + + p9_req->status = REQ_STATUS_SENT; + virt_wmb(); /* write ring before updating pointer */ + prod += size; + ring->intf->out_prod = prod; + spin_unlock_irqrestore(&ring->lock, flags); + notify_remote_via_irq(ring->irq); + return 0; }