Re: [Qemu-devel] [PATCH v2 1/6] block: Fragment reads to max transfer length

[Eric Blake <eblake@redhat.com>]

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On 07/08/2016 04:35 PM, Eric Blake wrote:
> Drivers should be able to rely on the block layer honoring the
> max transfer length, rather than needing to return -EINVAL
> (iscsi) or manually fragment things (nbd).  This patch adds
> the fragmentation in the block layer, after requests have been
> aligned (fragmenting before alignment would lead to multiple
> unaligned requests, rather than just the head and tail).
> 
> The return value was previously nebulous on success (sometimes
> zero, sometimes the length read); since we never have a short
> read, and since fragmenting may store yet another positive
> value in 'ret', change the function to always return the
> incoming 'bytes' value on success.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> 
> ---
> v2: Fix uninitialized use of 'ret' for an all-zero read beyond eof

Uggh. Something I did here and not in v1 is now causing 'make
check-qtest' failures. Please don't merge until I've posted v3.


-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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