RE: [PATCH] SCSI driver for VMware's virtual HBA - V3.

From: Alok Kataria
Date: Tue Sep 08 2009 - 21:07:56 EST


Hi Chetan,

> Alok,
>
> (This is just a optimization.You don't need it in order to get your
> code merged upstream.You can always patch it later on)In fact hw_lock
> should be split into two locks -
>
> req_path_lock(aka tx_lock) and
> cmpl_path_lock(aka rx_lock).
>
> You can then have a full-duplex channel.
>
> Revised-code -
> ::pvscsi_acquire_context->spin_lock_irqsave(tx_lock)
> ::pvscsi_isr->spin_lock_irqsave(rx_lock)
> ::some_future_napi_style_pvrx_poll_func->spin_lock_irqsave(rx_lock)
>
> ::for aborts synchronize on the rx_lock so that you know what's
> completed and what's not.
>

I agree about the optimization. Though IMO this will be more attractive
once we have a device which supports multiple queue pairs.
Anyways, let me keep this on my plate, I will check how much of an
benefit this gets us and will decide if this should be done, but as you
suggested this is for later.

Thanks for taking a look.

--Alok

> This is the kind of common code that should be provided by the bottom
> edge of the scsi-layer so that all the scsi-LLDD's can split their
> tx/rx paths!
>



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