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Date: Fri, 23 Jul 2010 12:50:12 +0200
From: Kevin Wolf <kwolf@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] block: default to 0 minimal / optiomal I/O
	size
References: <20100723073504.GA28166@lst.de>
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To: Christoph Hellwig <hch@lst.de>
Cc: qemu-devel@nongnu.org

Am 23.07.2010 09:35, schrieb Christoph Hellwig:
> Currently we set them to 512 bytes unless manually specified.  Unforuntaly
> some brain-dead partitioning tools create unaligned partitions if they
> get low enough optiomal I/O size values, so don't report any at all
> unless explicitly set.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Index: qemu/block_int.h
> ===================================================================
> --- qemu.orig/block_int.h	2010-07-23 09:26:07.660494681 +0200
> +++ qemu/block_int.h	2010-07-23 09:26:20.323494685 +0200
> @@ -243,7 +243,7 @@ static inline unsigned int get_physical_
>                         _conf.logical_block_size, 512),                  \
>      DEFINE_PROP_UINT16("physical_block_size", _state,                   \
>                         _conf.physical_block_size, 512),                 \
> -    DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 512),  \
> -    DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 512)
> +    DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0),  \
> +    DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0)
>  
>  #endif /* BLOCK_INT_H */

This isn't reverting to the state before we reported anything, but it
reports values of 0 now. Is this defined for both virtio-blk and SCSI to
mean the same as no report at all? Or should we rather not advertise
VIRTIO_BLK_F_TOPOLOGY (and the SCSI equivalent) in this case?

Kevin