Subject: Re: sun3: si_dma_alloc: excessive xlen=0x10000
To: None <thorpej@wasabisystems.com>
From: Izumi Tsutsui <tsutsui@ceres.dti.ne.jp>
List: current-users
Date: 06/15/2003 02:46:11
In article <D6EF96FC-9E8C-11D7-88A6-000A957650EC@wasabisystems.com>
thorpej@wasabisystems.com wrote:

> On Saturday, June 14, 2003, at 10:21  AM, Izumi Tsutsui wrote:
> 
> > There is the following comments in si.c:
> >>> 	 * Never attempt single transfers of more than 63k, because
> >>> 	 * our count register may be only 16 bits (an OBIO adapter).
> >>> 	 * This should never happen since already bounded by minphys().
> >
> > si_minphys() in sys/arch/sun3/dev/si.c limits b_count < MAX_DMA_LEN,
> > but why xlen is larger than MAX_DMA_LEN in si_dma_alloc()?
> 
> The issue here is that the file system code does not use minphys() to 
> clamp the transfers.

Hmm, then I'm afraid there are many MI/MD SCSI drivers which
assume each transfer size is clamped by their own minphys functions..
---
Izumi Tsutsui
tsutsui@ceres.dti.ne.jp