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Date: Thu, 30 Apr 2015 12:32:25 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [RFC PATCH 6/8] tap: Drop tap_can_send
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To: Jason Wang <jasowang@redhat.com>, Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org, Vincenzo Maffione <v.maffione@gmail.com>, Stefan Hajnoczi <stefanha@redhat.com>, Giuseppe Lettieri <g.lettieri@iet.unipi.it>, Luigi Rizzo <rizzo@iet.unipi.it>



On 30/04/2015 10:59, Jason Wang wrote:
>>
>>  
>> +        /* If !can_send, we will want to disable the read poll, but
>> we still
>> +         * need the send completion callback to enable it again,
>> which is a
>> +         * sign of peer becoming ready.  So call the send function
>> +         * regardlessly of can_send.
>> +         */
> 
> It was probably not safe to depend on sent_cb to re-enable the polling.
> Since the packet could be purged in some conditions (e.g
> net_vm_change_state_handler()). So tap_send_completed won't be called in
> this case.

Doesn't qemu_net_queue_purge also call the sent_cb?

Paolo