Re: [RFC PATCH 0/4] block layer: split block APIs in graph and I/O

[Stefan Hajnoczi]

On Wed, Sep 08, 2021 at 09:10:17AM -0400, Emanuele Giuseppe Esposito wrote:
> Currently, block layer APIs like block-backend.h contain a mix of
> functions that are either running in the main loop and under the
> BQL, or are thread-safe functions and run in iothreads performing I/O.
> The functions running under BQL also take care of modifying the
> block graph, by using drain and/or aio_context_acquire/release.
> This makes it very confusing to understand where each function
> runs, and what assumptions it provided with regards to thread
> safety.
> 
> We call the functions running under BQL "graph API", and 
> distinguish them from the thread-safe "I/O API".

Maybe "BQL" is clearer than "graph" because not all functions classified
as "graph" need to traverse/modify the graph.

Stefan

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