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Re: [Qemu-devel] [PATCH v2 7/9] xen/9pfs: implement in/out_iov_from_pdu
From: |
Greg Kurz |
Subject: |
Re: [Qemu-devel] [PATCH v2 7/9] xen/9pfs: implement in/out_iov_from_pdu and vmarshal/vunmarshal |
Date: |
Wed, 15 Mar 2017 11:58:41 +0100 |
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.
> + 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.
> + 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.
> + 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.
> + 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.
> + 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.
> + 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)
pgpP2pBQaZQhh.pgp
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[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