Re: [Qemu-devel] [PATCH v2 1/5] net/dump: Add support for receive_iov function

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 10/13/2015 06:39 PM, Thomas Huth wrote:
> Adding a proper receive_iov function to the net dump module.
> This will make it easier to support the dump filter feature for
> the -netdev option in later patches.
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Reviewed-by: Yang Hongyang <yanghy@cn.fujitsu.com>

> ---
>   net/dump.c | 24 +++++++++++++++++++++---
>   1 file changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/net/dump.c b/net/dump.c
> index 08259af..aa0d45d 100644
> --- a/net/dump.c
> +++ b/net/dump.c
> @@ -25,6 +25,7 @@
>   #include "clients.h"
>   #include "qemu-common.h"
>   #include "qemu/error-report.h"
> +#include "qemu/iov.h"
>   #include "qemu/log.h"
>   #include "qemu/timer.h"
>   #include "hub.h"
> @@ -57,12 +58,15 @@ struct pcap_sf_pkthdr {
>       uint32_t len;
>   };
>
> -static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
> +static ssize_t dump_receive_iov(NetClientState *nc, const struct iovec *iov,
> +                                int cnt)
>   {
>       DumpState *s = DO_UPCAST(DumpState, nc, nc);
>       struct pcap_sf_pkthdr hdr;
>       int64_t ts;
>       int caplen;
> +    size_t size = iov_size(iov, cnt);
> +    struct iovec dumpiov[cnt + 1];
>
>       /* Early return in case of previous error. */
>       if (s->fd < 0) {
> @@ -76,8 +80,12 @@ static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
>       hdr.ts.tv_usec = ts % 1000000;
>       hdr.caplen = caplen;
>       hdr.len = size;
> -    if (write(s->fd, &hdr, sizeof(hdr)) != sizeof(hdr) ||
> -        write(s->fd, buf, caplen) != caplen) {
> +
> +    dumpiov[0].iov_base = &hdr;
> +    dumpiov[0].iov_len = sizeof(hdr);
> +    cnt = iov_copy(&dumpiov[1], cnt, iov, cnt, 0, caplen);
> +
> +    if (writev(s->fd, dumpiov, cnt + 1) != sizeof(hdr) + caplen) {
>           qemu_log("-net dump write error - stop dump\n");
>           close(s->fd);
>           s->fd = -1;
> @@ -86,6 +94,15 @@ static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
>       return size;
>   }
>
> +static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
> +{
> +    struct iovec iov = {
> +        .iov_base = (void *)buf,
> +        .iov_len = size
> +    };
> +    return dump_receive_iov(nc, &iov, 1);
> +}
> +
>   static void dump_cleanup(NetClientState *nc)
>   {
>       DumpState *s = DO_UPCAST(DumpState, nc, nc);
> @@ -97,6 +114,7 @@ static NetClientInfo net_dump_info = {
>       .type = NET_CLIENT_OPTIONS_KIND_DUMP,
>       .size = sizeof(DumpState),
>       .receive = dump_receive,
> +    .receive_iov = dump_receive_iov,
>       .cleanup = dump_cleanup,
>   };
>
>

-- 
Thanks,
Yang.