diff mbox

[v2,6/9] xen/9pfs: receive requests from the frontend

Message ID 1489449360-14411-6-git-send-email-sstabellini@kernel.org (mailing list archive)
State New, archived
Headers show

Commit Message

Stefano Stabellini March 13, 2017, 11:55 p.m. UTC
Upon receiving an event channel notification from the frontend, schedule
the bottom half. From the bottom half, read one request from the ring,
create a pdu and call pdu_submit to handle it.

For now, only handle one request per ring at a time.

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
CC: anthony.perard@citrix.com
CC: jgross@suse.com
CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
CC: Greg Kurz <groug@kaod.org>
---
 hw/9pfs/xen-9p-backend.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

Comments

Greg Kurz March 15, 2017, 10:51 a.m. UTC | #1
On Mon, 13 Mar 2017 16:55:57 -0700
Stefano Stabellini <sstabellini@kernel.org> wrote:

> Upon receiving an event channel notification from the frontend, schedule
> the bottom half. From the bottom half, read one request from the ring,
> create a pdu and call pdu_submit to handle it.
> 
> For now, only handle one request per ring at a time.
> 
> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> CC: anthony.perard@citrix.com
> CC: jgross@suse.com
> CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> CC: Greg Kurz <groug@kaod.org>
> ---
>  hw/9pfs/xen-9p-backend.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
> index 0e4a133..741dd31 100644
> --- a/hw/9pfs/xen-9p-backend.c
> +++ b/hw/9pfs/xen-9p-backend.c
> @@ -94,12 +94,59 @@ static int xen_9pfs_init(struct XenDevice *xendev)
>      return 0;
>  }
>  
> +static int xen_9pfs_receive(struct Xen9pfsRing *ring)

Coding style for structured types.

> +{
> +    struct xen_9pfs_header h;
> +    RING_IDX cons, prod, masked_prod, masked_cons;
> +    V9fsPDU *pdu;
> +
> +    if (ring->inprogress) {
> +        return 0;
> +    }
> +
> +    cons = ring->intf->out_cons;
> +    prod = ring->intf->out_prod;
> +    xen_rmb();
> +
> +    if (xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) < sizeof(h)) {
> +        return 0;
> +    }
> +    ring->inprogress = true;
> +
> +    masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
> +    masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
> +
> +    xen_9pfs_read_packet(ring->ring.out, masked_prod, &masked_cons,
> +                         XEN_9PFS_RING_SIZE, (uint8_t*) &h, sizeof(h));
> +
> +    pdu = pdu_alloc(&ring->priv->state);

pdu_alloc() can theoretically return NULL. Maybe add a comment to
indicate this won't happen because "for now [we] only handle one
request per ring at a time".

> +    pdu->size = h.size;
> +    pdu->id = h.id;
> +    pdu->tag = h.tag;
> +    ring->out_size = h.size;
> +    ring->out_cons = cons + h.size;
> +
> +    qemu_co_queue_init(&pdu->complete);
> +    pdu_submit(pdu);
> +
> +    return 0;
> +}
> +
>  static void xen_9pfs_bh(void *opaque)
>  {
> +    struct Xen9pfsRing *ring = opaque;

Coding style for structured types.

> +    xen_9pfs_receive(ring);
>  }
>  
>  static void xen_9pfs_evtchn_event(void *opaque)
>  {
> +    struct Xen9pfsRing *ring = opaque;

Coding style for structured types.

> +    evtchn_port_t port;
> +
> +    port = xenevtchn_pending(ring->evtchndev);
> +    xenevtchn_unmask(ring->evtchndev, port);
> +
> +    qemu_bh_schedule(ring->bh);
>  }
>  
>  static int xen_9pfs_free(struct XenDevice *xendev)
Greg Kurz March 15, 2017, 11:53 a.m. UTC | #2
On Mon, 13 Mar 2017 16:55:57 -0700
Stefano Stabellini <sstabellini@kernel.org> wrote:

> Upon receiving an event channel notification from the frontend, schedule
> the bottom half. From the bottom half, read one request from the ring,
> create a pdu and call pdu_submit to handle it.
> 
> For now, only handle one request per ring at a time.
> 
> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> CC: anthony.perard@citrix.com
> CC: jgross@suse.com
> CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> CC: Greg Kurz <groug@kaod.org>
> ---

Oops, one more remark I forgot in my the previous mail. See below.

>  hw/9pfs/xen-9p-backend.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
> index 0e4a133..741dd31 100644
> --- a/hw/9pfs/xen-9p-backend.c
> +++ b/hw/9pfs/xen-9p-backend.c
> @@ -94,12 +94,59 @@ static int xen_9pfs_init(struct XenDevice *xendev)
>      return 0;
>  }
>  
> +static int xen_9pfs_receive(struct Xen9pfsRing *ring)
> +{
> +    struct xen_9pfs_header h;
> +    RING_IDX cons, prod, masked_prod, masked_cons;
> +    V9fsPDU *pdu;
> +
> +    if (ring->inprogress) {
> +        return 0;
> +    }
> +
> +    cons = ring->intf->out_cons;
> +    prod = ring->intf->out_prod;
> +    xen_rmb();
> +
> +    if (xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) < sizeof(h)) {
> +        return 0;
> +    }
> +    ring->inprogress = true;
> +
> +    masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
> +    masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
> +
> +    xen_9pfs_read_packet(ring->ring.out, masked_prod, &masked_cons,
> +                         XEN_9PFS_RING_SIZE, (uint8_t*) &h, sizeof(h));
> +
> +    pdu = pdu_alloc(&ring->priv->state);
> +    pdu->size = h.size;

9P uses little-endian, so this should be:

    pdu->size = le32_to_cpu(h.size);

> +    pdu->id = h.id;
> +    pdu->tag = h.tag;

and:

    pdu->tag = le16_to_cpu(h.tag);

> +    ring->out_size = h.size;
> +    ring->out_cons = cons + h.size;

Same here.

> +
> +    qemu_co_queue_init(&pdu->complete);
> +    pdu_submit(pdu);
> +
> +    return 0;
> +}
> +
>  static void xen_9pfs_bh(void *opaque)
>  {
> +    struct Xen9pfsRing *ring = opaque;
> +    xen_9pfs_receive(ring);
>  }
>  
>  static void xen_9pfs_evtchn_event(void *opaque)
>  {
> +    struct Xen9pfsRing *ring = opaque;
> +    evtchn_port_t port;
> +
> +    port = xenevtchn_pending(ring->evtchndev);
> +    xenevtchn_unmask(ring->evtchndev, port);
> +
> +    qemu_bh_schedule(ring->bh);
>  }
>  
>  static int xen_9pfs_free(struct XenDevice *xendev)
Stefano Stabellini March 15, 2017, 9:56 p.m. UTC | #3
On Wed, 15 Mar 2017, Greg Kurz wrote:
> On Mon, 13 Mar 2017 16:55:57 -0700
> Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> > Upon receiving an event channel notification from the frontend, schedule
> > the bottom half. From the bottom half, read one request from the ring,
> > create a pdu and call pdu_submit to handle it.
> > 
> > For now, only handle one request per ring at a time.
> > 
> > Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> > CC: anthony.perard@citrix.com
> > CC: jgross@suse.com
> > CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> > CC: Greg Kurz <groug@kaod.org>
> > ---
> >  hw/9pfs/xen-9p-backend.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 47 insertions(+)
> > 
> > diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
> > index 0e4a133..741dd31 100644
> > --- a/hw/9pfs/xen-9p-backend.c
> > +++ b/hw/9pfs/xen-9p-backend.c
> > @@ -94,12 +94,59 @@ static int xen_9pfs_init(struct XenDevice *xendev)
> >      return 0;
> >  }
> >  
> > +static int xen_9pfs_receive(struct Xen9pfsRing *ring)
> 
> Coding style for structured types.

I'll fix


> > +{
> > +    struct xen_9pfs_header h;
> > +    RING_IDX cons, prod, masked_prod, masked_cons;
> > +    V9fsPDU *pdu;
> > +
> > +    if (ring->inprogress) {
> > +        return 0;
> > +    }
> > +
> > +    cons = ring->intf->out_cons;
> > +    prod = ring->intf->out_prod;
> > +    xen_rmb();
> > +
> > +    if (xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) < sizeof(h)) {
> > +        return 0;
> > +    }
> > +    ring->inprogress = true;
> > +
> > +    masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
> > +    masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
> > +
> > +    xen_9pfs_read_packet(ring->ring.out, masked_prod, &masked_cons,
> > +                         XEN_9PFS_RING_SIZE, (uint8_t*) &h, sizeof(h));
> > +
> > +    pdu = pdu_alloc(&ring->priv->state);
> 
> pdu_alloc() can theoretically return NULL. Maybe add a comment to
> indicate this won't happen because "for now [we] only handle one
> request per ring at a time".

OK


> > +    pdu->size = h.size;
> > +    pdu->id = h.id;
> > +    pdu->tag = h.tag;
> > +    ring->out_size = h.size;
> > +    ring->out_cons = cons + h.size;
> > +
> > +    qemu_co_queue_init(&pdu->complete);
> > +    pdu_submit(pdu);
> > +
> > +    return 0;
> > +}
> > +
> >  static void xen_9pfs_bh(void *opaque)
> >  {
> > +    struct Xen9pfsRing *ring = opaque;
> 
> Coding style for structured types.

OK


> > +    xen_9pfs_receive(ring);
> >  }
> >  
> >  static void xen_9pfs_evtchn_event(void *opaque)
> >  {
> > +    struct Xen9pfsRing *ring = opaque;
> 
> Coding style for structured types.

OK


> > +    evtchn_port_t port;
> > +
> > +    port = xenevtchn_pending(ring->evtchndev);
> > +    xenevtchn_unmask(ring->evtchndev, port);
> > +
> > +    qemu_bh_schedule(ring->bh);
> >  }
> >  
> >  static int xen_9pfs_free(struct XenDevice *xendev)
Stefano Stabellini March 15, 2017, 10:03 p.m. UTC | #4
On Wed, 15 Mar 2017, Greg Kurz wrote:
> On Mon, 13 Mar 2017 16:55:57 -0700
> Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> > Upon receiving an event channel notification from the frontend, schedule
> > the bottom half. From the bottom half, read one request from the ring,
> > create a pdu and call pdu_submit to handle it.
> > 
> > For now, only handle one request per ring at a time.
> > 
> > Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> > CC: anthony.perard@citrix.com
> > CC: jgross@suse.com
> > CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> > CC: Greg Kurz <groug@kaod.org>
> > ---
> 
> Oops, one more remark I forgot in my the previous mail. See below.
> 
> >  hw/9pfs/xen-9p-backend.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 47 insertions(+)
> > 
> > diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
> > index 0e4a133..741dd31 100644
> > --- a/hw/9pfs/xen-9p-backend.c
> > +++ b/hw/9pfs/xen-9p-backend.c
> > @@ -94,12 +94,59 @@ static int xen_9pfs_init(struct XenDevice *xendev)
> >      return 0;
> >  }
> >  
> > +static int xen_9pfs_receive(struct Xen9pfsRing *ring)
> > +{
> > +    struct xen_9pfs_header h;
> > +    RING_IDX cons, prod, masked_prod, masked_cons;
> > +    V9fsPDU *pdu;
> > +
> > +    if (ring->inprogress) {
> > +        return 0;
> > +    }
> > +
> > +    cons = ring->intf->out_cons;
> > +    prod = ring->intf->out_prod;
> > +    xen_rmb();
> > +
> > +    if (xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) < sizeof(h)) {
> > +        return 0;
> > +    }
> > +    ring->inprogress = true;
> > +
> > +    masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
> > +    masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
> > +
> > +    xen_9pfs_read_packet(ring->ring.out, masked_prod, &masked_cons,
> > +                         XEN_9PFS_RING_SIZE, (uint8_t*) &h, sizeof(h));
> > +
> > +    pdu = pdu_alloc(&ring->priv->state);
> > +    pdu->size = h.size;
> 
> 9P uses little-endian, so this should be:
> 
>     pdu->size = le32_to_cpu(h.size);
> 
> > +    pdu->id = h.id;
> > +    pdu->tag = h.tag;
> 
> and:
> 
>     pdu->tag = le16_to_cpu(h.tag);
> 
> > +    ring->out_size = h.size;
> > +    ring->out_cons = cons + h.size;
> 
> Same here.

OK, thanks. Xen doesn't support big endian today, but they don't hurt.


> > +
> > +    qemu_co_queue_init(&pdu->complete);
> > +    pdu_submit(pdu);
> > +
> > +    return 0;
> > +}
> > +
> >  static void xen_9pfs_bh(void *opaque)
> >  {
> > +    struct Xen9pfsRing *ring = opaque;
> > +    xen_9pfs_receive(ring);
> >  }
> >  
> >  static void xen_9pfs_evtchn_event(void *opaque)
> >  {
> > +    struct Xen9pfsRing *ring = opaque;
> > +    evtchn_port_t port;
> > +
> > +    port = xenevtchn_pending(ring->evtchndev);
> > +    xenevtchn_unmask(ring->evtchndev, port);
> > +
> > +    qemu_bh_schedule(ring->bh);
> >  }
> >  
> >  static int xen_9pfs_free(struct XenDevice *xendev)
> 
>
diff mbox

Patch

diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
index 0e4a133..741dd31 100644
--- a/hw/9pfs/xen-9p-backend.c
+++ b/hw/9pfs/xen-9p-backend.c
@@ -94,12 +94,59 @@  static int xen_9pfs_init(struct XenDevice *xendev)
     return 0;
 }
 
+static int xen_9pfs_receive(struct Xen9pfsRing *ring)
+{
+    struct xen_9pfs_header h;
+    RING_IDX cons, prod, masked_prod, masked_cons;
+    V9fsPDU *pdu;
+
+    if (ring->inprogress) {
+        return 0;
+    }
+
+    cons = ring->intf->out_cons;
+    prod = ring->intf->out_prod;
+    xen_rmb();
+
+    if (xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) < sizeof(h)) {
+        return 0;
+    }
+    ring->inprogress = true;
+
+    masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
+    masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
+
+    xen_9pfs_read_packet(ring->ring.out, masked_prod, &masked_cons,
+                         XEN_9PFS_RING_SIZE, (uint8_t*) &h, sizeof(h));
+
+    pdu = pdu_alloc(&ring->priv->state);
+    pdu->size = h.size;
+    pdu->id = h.id;
+    pdu->tag = h.tag;
+    ring->out_size = h.size;
+    ring->out_cons = cons + h.size;
+
+    qemu_co_queue_init(&pdu->complete);
+    pdu_submit(pdu);
+
+    return 0;
+}
+
 static void xen_9pfs_bh(void *opaque)
 {
+    struct Xen9pfsRing *ring = opaque;
+    xen_9pfs_receive(ring);
 }
 
 static void xen_9pfs_evtchn_event(void *opaque)
 {
+    struct Xen9pfsRing *ring = opaque;
+    evtchn_port_t port;
+
+    port = xenevtchn_pending(ring->evtchndev);
+    xenevtchn_unmask(ring->evtchndev, port);
+
+    qemu_bh_schedule(ring->bh);
 }
 
 static int xen_9pfs_free(struct XenDevice *xendev)