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

[Alok Kataria <akataria@vmware.com>]

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!
>