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Date: Mon, 25 Mar 2013 14:07:27 +0100
From: Hans de Goede <hdegoede@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/8] qemu-char: Add fe_open tracking
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Amit Shah <amit.shah@redhat.com>, qemu-devel@nongnu.org

Hi,

On 03/25/2013 01:45 PM, Anthony Liguori wrote:
> Hans de Goede <hdegoede@redhat.com> writes:
>
>> Add tracking of the fe_open state to struct CharDriverState.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>   include/char/char.h | 1 +
>>   qemu-char.c         | 2 ++
>>   2 files changed, 3 insertions(+)
>>
>> diff --git a/include/char/char.h b/include/char/char.h
>> index dd8f39a..3174575 100644
>> --- a/include/char/char.h
>> +++ b/include/char/char.h
>> @@ -75,6 +75,7 @@ struct CharDriverState {
>>       char *label;
>>       char *filename;
>>       int be_open;
>> +    int fe_open;
>>       int avail_connections;
>>       QemuOpts *opts;
>>       QTAILQ_ENTRY(CharDriverState) next;
>> diff --git a/qemu-char.c b/qemu-char.c
>> index 55795d7..554d72f 100644
>> --- a/qemu-char.c
>> +++ b/qemu-char.c
>> @@ -3385,6 +3385,7 @@ void qemu_chr_fe_set_echo(struct CharDriverState *chr, bool echo)
>>
>>   void qemu_chr_fe_open(struct CharDriverState *chr)
>>   {
>> +    chr->fe_open = 1;
>>       if (chr->chr_guest_open) {
>>           chr->chr_guest_open(chr);
>>       }
>> @@ -3392,6 +3393,7 @@ void qemu_chr_fe_open(struct CharDriverState *chr)
>>
>>   void qemu_chr_fe_close(struct CharDriverState *chr)
>>   {
>> +    chr->fe_open = 0;
>
> Even though this gets rewritten later on, you should avoid calling the
> callback when open is called when fe_open=1.  Something like
>
> if (!chr->fe_open) {
>      return;
> }
>
> Then later when this becomes set_fe_open() the backend doesn't need to
> deal with double open/close.

Ok, will fix in the next iteration of this patchset.

Regards,

Hans