Re: [PATCH/RFT] libata "DMA timeout" fix

[Justin Cormack]

Thanks, testing James's fix on one machine at the moment. Will have
another six or so machines as a libata test farm tomorrow.

Justin


On Sat, 2004-02-28 at 21:23, Jeff Garzik wrote:
> James Bottomley wrote:
> > On Sat, 2004-02-28 at 13:10, Jeff Garzik wrote:
> > 
> >>===== drivers/scsi/libata-core.c 1.19 vs edited =====
> >>--- 1.19/drivers/scsi/libata-core.c	Wed Feb 25 22:41:13 2004
> >>+++ edited/drivers/scsi/libata-core.c	Sat Feb 28 14:03:18 2004
> >>@@ -2130,6 +2130,14 @@
> >> 				cmd->result = SAM_STAT_CHECK_CONDITION;
> >> 			else
> >> 				ata_to_sense_error(qc);
> >>+
> >>+			/* hack alert! we need this to get past the
> >>+			 * first check in scsi_done().  libata is the
> >>+			 * -only- user of ->eh_strategy_handler() in
> >>+			 * any kernel tree, which exposes some incorrect
> >>+			 * assumptions in the SCSI layer.
> >>+			 */
> >>+			scsi_add_timer(cmd, 2000 * HZ, NULL);
> >> 		} else {
> >> 			cmd->result = SAM_STAT_GOOD;
> >> 		}
> > 
> > 
> > You can't do this.  Supposing there command's delayed, the timer fires
> > and then the command returns with a sense error?  The done will go
> > through automatically completing the command, but your strategy handler
> > will still think it has a failed command to handle.
> 
> hmmm, yeah that will be a problem iff we are not already in the strategy 
> handler.
> 
> 
> > The correct fix is this, I think (uncompiled, but you get the idea):
> 
> Yeah, that's much better.  That function is not exported though ;-)
> 
> 	Jeff
> 
> 
> 
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