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Re: [Qemu-devel] [PATCH v2 7/9] xen/9pfs: implement in/out_iov_from_pdu
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH v2 7/9] xen/9pfs: implement in/out_iov_from_pdu and vmarshal/vunmarshal |
Date: |
Wed, 15 Mar 2017 14:58:42 -0700 (PDT) |
User-agent: |
Alpine 2.10 (DEB 1266 2009-07-14) |
On Wed, 15 Mar 2017, Greg Kurz wrote:
> On Mon, 13 Mar 2017 16:55:58 -0700
> Stefano Stabellini <address@hidden> wrote:
>
> > Implement xen_9pfs_init_in/out_iov_from_pdu and
> > xen_9pfs_pdu_vmarshal/vunmarshall by creating new sg pointing to the
> > data on the ring.
> >
> > This is safe as we only handle one request per ring at any given time.
> >
> > Signed-off-by: Stefano Stabellini <address@hidden>
> > CC: address@hidden
> > CC: address@hidden
> > CC: Aneesh Kumar K.V <address@hidden>
> > CC: Greg Kurz <address@hidden>
> > ---
> > hw/9pfs/xen-9p-backend.c | 91
> > ++++++++++++++++++++++++++++++++++++++++++++++--
> > 1 file changed, 89 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
> > index 741dd31..d72a749 100644
> > --- a/hw/9pfs/xen-9p-backend.c
> > +++ b/hw/9pfs/xen-9p-backend.c
> > @@ -48,12 +48,77 @@ typedef struct Xen9pfsDev {
> > struct Xen9pfsRing *rings;
> > } Xen9pfsDev;
> >
> > +static void xen_9pfs_in_sg(struct Xen9pfsRing *ring,
>
> Coding style for structured types.
OK
> > + struct iovec *in_sg,
> > + int *num,
> > + uint32_t idx,
> > + uint32_t size)
> > +{
> > + RING_IDX cons, prod, masked_prod, masked_cons;
> > +
> > + cons = ring->intf->in_cons;
> > + prod = ring->intf->in_prod;
> > + xen_rmb();
> > + masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
> > + masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
> > +
> > + if (masked_prod < masked_cons) {
> > + in_sg[0].iov_base = ring->ring.in + masked_prod;
> > + in_sg[0].iov_len = masked_cons - masked_prod;
> > + *num = 1;
> > + } else {
> > + in_sg[0].iov_base = ring->ring.in + masked_prod;
> > + in_sg[0].iov_len = XEN_9PFS_RING_SIZE - masked_prod;
> > + in_sg[1].iov_base = ring->ring.in;
> > + in_sg[1].iov_len = masked_cons;
> > + *num = 2;
> > + }
> > +}
> > +
> > +static void xen_9pfs_out_sg(struct Xen9pfsRing *ring,
>
> Coding style for structured types.
OK
> > + struct iovec *out_sg,
> > + int *num,
> > + uint32_t idx)
> > +{
> > + RING_IDX cons, prod, masked_prod, masked_cons;
> > +
> > + cons = ring->intf->out_cons;
> > + prod = ring->intf->out_prod;
> > + xen_rmb();
> > + masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
> > + masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
> > +
> > + if (masked_cons < masked_prod) {
> > + out_sg[0].iov_base = ring->ring.out + masked_cons;
> > + out_sg[0].iov_len = ring->out_size;
> > + *num = 1;
> > + } else {
> > + if (ring->out_size > (XEN_9PFS_RING_SIZE - masked_cons)) {
> > + out_sg[0].iov_base = ring->ring.out + masked_cons;
> > + out_sg[0].iov_len = XEN_9PFS_RING_SIZE - masked_cons;
> > + out_sg[1].iov_base = ring->ring.out;
> > + out_sg[1].iov_len = ring->out_size - (XEN_9PFS_RING_SIZE -
> > masked_cons);
> > + *num = 2;
> > + } else {
> > + out_sg[0].iov_base = ring->ring.out + masked_cons;
> > + out_sg[0].iov_len = ring->out_size;
> > + *num = 1;
> > + }
> > + }
> > +}
> > +
> > static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu,
> > size_t offset,
> > const char *fmt,
> > va_list ap)
> > {
> > - return 0;
> > + struct Xen9pfsDev *xen_9pfs = container_of(pdu->s, struct Xen9pfsDev,
> > state);
>
> Coding style for structured types.
OK
> > + struct iovec in_sg[2];
> > + int num;
> > +
> > + xen_9pfs_in_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings],
> > + in_sg, &num, pdu->idx, ROUND_UP(offset + 128, 512));
> > + return v9fs_iov_vmarshal(in_sg, num, offset, 0, fmt, ap);
> > }
> >
> > static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu,
> > @@ -61,13 +126,27 @@ static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu,
> > const char *fmt,
> > va_list ap)
> > {
> > - return 0;
> > + struct Xen9pfsDev *xen_9pfs = container_of(pdu->s, struct Xen9pfsDev,
> > state);
>
> Coding style for structured types.
OK
> > + struct iovec out_sg[2];
> > + int num;
> > +
> > + xen_9pfs_out_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings],
> > + out_sg, &num, pdu->idx);
> > + return v9fs_iov_vunmarshal(out_sg, num, offset, 0, fmt, ap);
> > }
> >
> > static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu,
> > struct iovec **piov,
> > unsigned int *pniov)
> > {
> > + struct Xen9pfsDev *xen_9pfs = container_of(pdu->s, struct Xen9pfsDev,
> > state);
> > + struct Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag %
> > xen_9pfs->num_rings];
>
> Coding style for structured types.
OK
> > + struct iovec *sg = g_malloc0(sizeof(*sg)*2);
> > + int num;
> > +
> > + xen_9pfs_out_sg(ring, sg, &num, pdu->idx);
> > + *piov = sg;
> > + *pniov = num;
> > }
> >
> > static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu,
> > @@ -75,6 +154,14 @@ static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu,
> > unsigned int *pniov,
> > size_t size)
> > {
> > + struct Xen9pfsDev *xen_9pfs = container_of(pdu->s, struct Xen9pfsDev,
> > state);
> > + struct Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag %
> > xen_9pfs->num_rings];
>
> Coding style for structured types.
OK :-)
> > + struct iovec *sg = g_malloc0(sizeof(*sg)*2);
> > + int num;
> > +
> > + xen_9pfs_in_sg(ring, sg, &num, pdu->idx, size);
> > + *piov = sg;
> > + *pniov = num;
> > }
> >
> > static void xen_9pfs_push_and_notify(V9fsPDU *pdu)
>
>
[Qemu-devel] [PATCH v2 7/9] xen/9pfs: implement in/out_iov_from_pdu and vmarshal/vunmarshal, Stefano Stabellini, 2017/03/13
[Qemu-devel] [PATCH v2 9/9] xen/9pfs: build and register Xen 9pfs backend, Stefano Stabellini, 2017/03/13
[Qemu-devel] [PATCH v2 6/9] xen/9pfs: receive requests from the frontend, Stefano Stabellini, 2017/03/13
Re: [Qemu-devel] [PATCH v2 6/9] xen/9pfs: receive requests from the frontend, Greg Kurz, 2017/03/15
Re: [Qemu-devel] [PATCH v2 6/9] xen/9pfs: receive requests from the frontend, Stefano Stabellini, 2017/03/15
[Qemu-devel] [PATCH v2 8/9] xen/9pfs: send responses back to the frontend, Stefano Stabellini, 2017/03/13
Re: [Qemu-devel] [PATCH v2 1/9] configure: change CONFIG_XEN_BACKEND to be a target property, Paolo Bonzini, 2017/03/14