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Date: Sun, 11 Mar 2012 19:22:35 +0400
From: Michael Tokarev <mjt@tls.msk.ru>
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Subject: Re: [Qemu-devel] [PATCHv2 5/7] Export qemu_sendv_recvv() and use it
 in qemu_sendv() and qemu_recvv()
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org

On 11.03.2012 19:00, Paolo Bonzini wrote:
> Il 11/03/2012 02:49, Michael Tokarev ha scritto:
>> Rename do_sendv_recvv() to qemu_sendv_recvv(),
>> change its last arg (do_send) from int to bool,
>> export it in qemu-common.h, and made the two
>> callers of it (qemu_sendv() and qemu_recvv())
>> to be trivial #defines just adding 5th arg.
> 
> GCC is smart and knows how to do tail calls in many cases.  Thus, I
> don't see very much the point of this patch.

The point is to allow qemu_sendv_recvv() to be used
directly, see the next patch
 [PATCHv2 6/7] cleanup qemu_co_sendv(), qemu_co_recvv() and friends
for an example, and see my previous attempt to address
all this with bdrv_* methods where reads and writes
are implemented in common functions and are split
back on layer boundary, just to go to a common
routine on the next layer.  Or worse yet, repeating
exactly the same code like in this 6/7 patch for
qemu_co_recvv() and qemu_co_sendv().

It is not about tail calls at all.

Thanks,

/mjt