Re: [Qemu-devel] [PATCH] iov: don't touch iov in iov_send_recv()

[Wen Congyang]

Ping again.

This patch is bugfix. The old discussion is here:
http://lists.nongnu.org/archive/html/qemu-devel/2015-02/msg00245.html

On 05/21/2015 09:50 AM, Wen Congyang wrote:
> Signed-off-by: Wen Congyang <address@hidden>
> ---
>  include/qemu/iov.h |  2 +-
>  util/iov.c         | 14 +++++++++++++-
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/include/qemu/iov.h b/include/qemu/iov.h
> index 68d25f2..569b2c2 100644
> --- a/include/qemu/iov.h
> +++ b/include/qemu/iov.h
> @@ -75,7 +75,7 @@ size_t iov_memset(const struct iovec *iov, const unsigned 
> int iov_cnt,
>   * For iov_send_recv() _whole_ area being sent or received
>   * should be within the iovec, not only beginning of it.
>   */
> -ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
> +ssize_t iov_send_recv(int sockfd, const struct iovec *iov, unsigned iov_cnt,
>                        size_t offset, size_t bytes, bool do_send);
>  #define iov_recv(sockfd, iov, iov_cnt, offset, bytes) \
>    iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, false)
> diff --git a/util/iov.c b/util/iov.c
> index 2fb18e6..a0d5934 100644
> --- a/util/iov.c
> +++ b/util/iov.c
> @@ -133,7 +133,7 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned 
> iov_cnt, bool do_send)
>  #endif
>  }
>  
> -ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
> +ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt,
>                        size_t offset, size_t bytes,
>                        bool do_send)
>  {
> @@ -141,6 +141,16 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, 
> unsigned iov_cnt,
>      ssize_t ret;
>      size_t orig_len, tail;
>      unsigned niov;
> +    struct iovec *local_iov, *iov;
> +
> +    if (bytes <= 0) {
> +        return 0;
> +    }
> +
> +    local_iov = g_new0(struct iovec, iov_cnt);
> +    iov_copy(local_iov, iov_cnt, _iov, iov_cnt, offset, bytes);
> +    offset = 0;
> +    iov = local_iov;
>  
>      while (bytes > 0) {
>          /* Find the start position, skipping `offset' bytes:
> @@ -187,6 +197,7 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, 
> unsigned iov_cnt,
>  
>          if (ret < 0) {
>              assert(errno != EINTR);
> +            g_free(local_iov);
>              if (errno == EAGAIN && total > 0) {
>                  return total;
>              }
> @@ -205,6 +216,7 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, 
> unsigned iov_cnt,
>          bytes -= ret;
>      }
>  
> +    g_free(local_iov);
>      return total;
>  }
>  
>