Re: [Xen-devel] [PATCH] cxenstored: correct calculation of data/space in the ring

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 16/11/15 18:01, Ian Jackson wrote:
> Wei Liu writes ("[PATCH] cxenstored: correct calculation of data/space in the 
> ring"):
>> The cxenstored implementation can't handle cross ring boundary read and
>> write. It gets aways with buggy behaviour because upper layer won't
>> sleep when short-write or short-read occurs.
> I don't understand why you think this is a bug.

It is exactly the same bug as I fixed in c/s 8a2c11f8

The short reads/writes themselves aren't inherently a problem.  They are
genuine signals that the server should wait for the client to
produce/consume more data.

However, the low level functions erroneously return a short read/write
when hitting the ring boundary when there is actually more space/data. 
This causes a protocol stall as the server incorrectly believes that the
client has the next action to perform.

~Andrew

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