Re: [Qemu-devel] [PATCHv3 8/9] cleanup qemu_co_sendv(), qemu_co_recvv() and friends

[Paolo Bonzini <pbonzini@redhat.com>]

Il 12/03/2012 20:14, Michael Tokarev ha scritto:
> The same as for non-coroutine versions in previous
> patches: rename arguments to be more obvious, change
> type of arguments from int to size_t where appropriate,
> and use common code for send and receive paths (with
> one extra argument) since these are exactly the same.
> Use common qemu_sendv_recvv() directly.
> 
> qemu_co_sendv(), qemu_co_recvv(), and qemu_co_recv()
> are now trivial #define's merely adding one extra arg.
> 
> qemu_co_sendv() and qemu_co_recvv() callers are
> converted to different argument order.
> 
> Also add comment near qemu_sendv() and qemu_recvv()
> stating that these are now unused.
> 
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  block/nbd.c         |    4 +-
>  block/sheepdog.c    |    6 ++--
>  qemu-common.h       |   39 ++++++++++++------------
>  qemu-coroutine-io.c |   82 +++++++++++++++-----------------------------------
>  4 files changed, 49 insertions(+), 82 deletions(-)
> 
> diff --git a/block/nbd.c b/block/nbd.c
> index 161b299..9919acc 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -194,7 +194,7 @@ static int nbd_co_send_request(BDRVNBDState *s, struct nbd_request *request,
>                              nbd_have_request, NULL, s);
>      rc = nbd_send_request(s->sock, request);
>      if (rc != -1 && iov) {
> -        ret = qemu_co_sendv(s->sock, iov, request->len, offset);
> +        ret = qemu_co_sendv(s->sock, iov, offset, request->len);
>          if (ret != request->len) {
>              errno = -EIO;
>              rc = -1;
> @@ -221,7 +221,7 @@ static void nbd_co_receive_reply(BDRVNBDState *s, struct nbd_request *request,
>          reply->error = EIO;
>      } else {
>          if (iov && reply->error == 0) {
> -            ret = qemu_co_recvv(s->sock, iov, request->len, offset);
> +            ret = qemu_co_recvv(s->sock, iov, offset, request->len);
>              if (ret != request->len) {
>                  reply->error = EIO;
>              }
> diff --git a/block/sheepdog.c b/block/sheepdog.c
> index 00276f6f..1083f27 100644
> --- a/block/sheepdog.c
> +++ b/block/sheepdog.c
> @@ -657,8 +657,8 @@ static void coroutine_fn aio_read_response(void *opaque)
>          }
>          break;
>      case AIOCB_READ_UDATA:
> -        ret = qemu_co_recvv(fd, acb->qiov->iov, rsp.data_length,
> -                            aio_req->iov_offset);
> +        ret = qemu_co_recvv(fd, acb->qiov->iov,
> +                            aio_req->iov_offset, rsp.data_length);
>          if (ret < 0) {
>              error_report("failed to get the data, %s", strerror(errno));
>              goto out;
> @@ -924,7 +924,7 @@ static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
>      }
>  
>      if (wlen) {
> -        ret = qemu_co_sendv(s->fd, iov, wlen, aio_req->iov_offset);
> +        ret = qemu_co_sendv(s->fd, iov, aio_req->iov_offset, wlen);
>          if (ret < 0) {
>              qemu_co_mutex_unlock(&s->lock);
>              error_report("failed to send a data, %s", strerror(errno));
> diff --git a/qemu-common.h b/qemu-common.h
> index b01d84c..eae1bde 100644
> --- a/qemu-common.h
> +++ b/qemu-common.h
> @@ -207,6 +207,8 @@ int qemu_pipe(int pipefd[2]);
>   */
>  ssize_t qemu_sendv_recvv(int sockfd, struct iovec *iov,
>                           size_t offset, size_t bytes, bool do_sendv);
> +/* these are basically unused now when everything
> + * switched is using coroutine versions */
>  #define qemu_recvv(sockfd, iov, offset, bytes) \
>    qemu_sendv_recvv(sockfd, iov, offset, bytes, false)
>  #define qemu_sendv(sockfd, iov, offset, bytes) \
> @@ -306,32 +308,29 @@ struct qemu_work_item {
>  void qemu_init_vcpu(void *env);
>  #endif
>  
> -/**
> - * Sends an iovec (or optionally a part of it) down a socket, yielding
> - * when the socket is full.
> - */
> -int qemu_co_sendv(int sockfd, struct iovec *iov,
> -                  int len, int iov_offset);
>  
>  /**
> - * Receives data into an iovec (or optionally into a part of it) from
> - * a socket, yielding when there is no data in the socket.
> + * Sends a (part of) iovec down a socket, yielding when the socket is full, or
> + * Receives data into a (part of) iovec from a socket,
> + * yielding when there is no data in the socket.
> + * The same interface as qemu_sendv_recvv(), with added yielding.
> + * XXX should mark these as coroutine_fn
>   */
> -int qemu_co_recvv(int sockfd, struct iovec *iov,
> -                  int len, int iov_offset);
> -
> +ssize_t qemu_co_sendv_recvv(int sockfd, struct iovec *iov,
> +                            size_t offset, size_t bytes, bool do_sendv);
> +#define qemu_co_recvv(sockfd, iov, offset, bytes) \
> +  qemu_co_sendv_recvv(sockfd, iov, offset, bytes, false)
> +#define qemu_co_sendv(sockfd, iov, offset, bytes) \
> +  qemu_co_sendv_recvv(sockfd, iov, offset, bytes, true)
>  
>  /**
> - * Sends a buffer down a socket, yielding when the socket is full.
> + * The same as above, but with just a single buffer
>   */
> -int qemu_co_send(int sockfd, void *buf, int len);
> -
> -/**
> - * Receives data into a buffer from a socket, yielding when there
> - * is no data in the socket.
> - */
> -int qemu_co_recv(int sockfd, void *buf, int len);
> -
> +ssize_t qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_sendv);
> +#define qemu_co_recv(sockfd, buf, bytes) \
> +  qemu_co_send_recv(sockfd, buf, bytes, false)
> +#define qemu_co_send(sockfd, buf, bytes) \
> +  qemu_co_send_recv(sockfd, buf, bytes, true)
>  
>  typedef struct QEMUIOVector {
>      struct iovec *iov;
> diff --git a/qemu-coroutine-io.c b/qemu-coroutine-io.c
> index df8ff21..7c978ea 100644
> --- a/qemu-coroutine-io.c
> +++ b/qemu-coroutine-io.c
> @@ -26,71 +26,39 @@
>  #include "qemu_socket.h"
>  #include "qemu-coroutine.h"
>  
> -int coroutine_fn qemu_co_recvv(int sockfd, struct iovec *iov,
> -                               int len, int iov_offset)
> +ssize_t coroutine_fn
> +qemu_co_sendv_recvv(int sockfd, struct iovec *iov,
> +                    size_t offset, size_t bytes, bool do_sendv)
>  {
> -    int total = 0;
> -    int ret;
> -    while (len) {
> -        ret = qemu_recvv(sockfd, iov, iov_offset + total, len);
> -        if (ret < 0) {
> +    size_t done = 0;
> +    ssize_t ret;
> +    while (done < bytes) {
> +        ret = qemu_sendv_recvv(sockfd, iov,
> +                               offset + done, bytes - done, do_sendv);
> +        if (ret > 0) {
> +            done += ret;
> +        } else if (ret < 0) {
>              if (errno == EAGAIN) {
>                  qemu_coroutine_yield();
> -                continue;
> -            }
> -            if (total == 0) {
> -                total = -1;
> -            }
> -            break;
> -        }
> -        if (ret == 0) {
> -            break;
> -        }
> -        total += ret, len -= ret;
> -    }
> -
> -    return total;
> -}
> -
> -int coroutine_fn qemu_co_sendv(int sockfd, struct iovec *iov,
> -                               int len, int iov_offset)
> -{
> -    int total = 0;
> -    int ret;
> -    while (len) {
> -        ret = qemu_sendv(sockfd, iov, iov_offset + total, len);
> -        if (ret < 0) {
> -            if (errno == EAGAIN) {
> -                qemu_coroutine_yield();
> -                continue;
> -            }
> -            if (total == 0) {
> -                total = -1;
> +            } else if (done == 0) {
> +                return -1;
> +            } else {
> +                break;
>              }
> +        } else if (ret == 0 && !do_sendv) {
> +            /* write (send) should never return 0.
> +             * read (recv) returns 0 for end-of-file (-data).
> +             * In both cases there's little point retrying,
> +             * but we do for write anyway, just in case */
>              break;
>          }
> -        total += ret, len -= ret;
>      }
> -
> -    return total;
> +    return done;
>  }
>  
> -int coroutine_fn qemu_co_recv(int sockfd, void *buf, int len)
> +ssize_t coroutine_fn
> +qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_sendv)
>  {
> -    struct iovec iov;
> -
> -    iov.iov_base = buf;
> -    iov.iov_len = len;
> -
> -    return qemu_co_recvv(sockfd, &iov, len, 0);
> -}
> -
> -int coroutine_fn qemu_co_send(int sockfd, void *buf, int len)
> -{
> -    struct iovec iov;
> -
> -    iov.iov_base = buf;
> -    iov.iov_len = len;
> -
> -    return qemu_co_sendv(sockfd, &iov, len, 0);
> +    struct iovec iov = { .iov_base = buf, .iov_len = bytes };
> +    return qemu_co_sendv_recvv(sockfd, &iov, 0, bytes, do_sendv);
>  }

Looks good.

Paolo