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Date: Mon, 25 Apr 2011 15:27:20 +0530
From: Amit Shah <amit.shah@redhat.com>
Message-ID: <20110425095720.GA8308@amit-x200.redhat.com>
References: <20110422125943.2F24E6FC039@msa105.auone-net.jp>
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Subject: Re: [Qemu-devel] [PATCH] char: Allow devices to use a single
 multiplexed chardev.
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To: Kusanagi Kouichi <slash@ac.auone-net.jp>
Cc: qemu-devel@nongnu.org

On (Fri) 22 Apr 2011 [21:59:42], Kusanagi Kouichi wrote:
> This fixes regression caused by commit
> 2d6c1ef40f3678ab47a4d14fb5dadaa486bfcda6
> ("char: Prevent multiple devices opening same chardev").

What's the regression?  How do I test it?

> Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp>
> ---
>  hw/qdev-properties.c |    4 ++--
>  qemu-char.c          |    5 ++++-
>  qemu-char.h          |    2 +-
>  3 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
> index 1088a26..0eed712 100644
> --- a/hw/qdev-properties.c
> +++ b/hw/qdev-properties.c
> @@ -354,10 +354,10 @@ static int parse_chr(DeviceState *dev, Property *prop, const char *str)
>      if (*ptr == NULL) {
>          return -ENOENT;
>      }
> -    if ((*ptr)->assigned) {
> +    if ((*ptr)->avail < 1) {
>          return -EEXIST;
>      }
> -    (*ptr)->assigned = 1;
> +    --(*ptr)->avail;
>      return 0;
>  }
>  
> diff --git a/qemu-char.c b/qemu-char.c
> index 03858d4..f08f2b8 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -199,7 +199,7 @@ void qemu_chr_add_handlers(CharDriverState *s,
>  {
>      if (!opaque) {
>          /* chr driver being released. */
> -        s->assigned = 0;
> +        ++s->avail;
>      }

Will just checking for handlers (fd_can_read, fd_read, fd_write not
NULL) here help instead of this patch?

>      s->chr_can_read = fd_can_read;
>      s->chr_read = fd_read;
> @@ -2544,7 +2544,10 @@ CharDriverState *qemu_chr_open_opts(QemuOpts *opts,
>          snprintf(base->label, len, "%s-base", qemu_opts_id(opts));
>          chr = qemu_chr_open_mux(base);
>          chr->filename = base->filename;
> +        chr->avail = MAX_MUX;
>          QTAILQ_INSERT_TAIL(&chardevs, chr, next);
> +    } else {
> +        chr->avail = 1;
>      }
>      chr->label = qemu_strdup(qemu_opts_id(opts));
>      return chr;
> diff --git a/qemu-char.h b/qemu-char.h
> index fb96eef..ebf3641 100644
> --- a/qemu-char.h
> +++ b/qemu-char.h
> @@ -70,7 +70,7 @@ struct CharDriverState {
>      char *label;
>      char *filename;
>      int opened;
> -    int assigned; /* chardev assigned to a device */
> +    int avail;
>      QTAILQ_ENTRY(CharDriverState) next;
>  };
>  
> -- 
> 1.7.4.4
> 
> 

		Amit