2001-12-13 20:42:44

by David Miller

[permalink] [raw]
Subject: that stupid aic7xxx AHC_NSEGS bug


We simply forget to initialize scb->sg_count in the non use_sg
case, so if the previous usage of that scb has sg_count==AHC_NSEGS
then we'd hit that panic erroneously. Here is the fix below.

"It can't possibly be my driver, something broke in some Linux
subsystem which is making my driver break", sheesh get over it
Justin...

--- drivers/scsi/aic7xxx/aic7xxx_linux.c.~1~ Fri Dec 7 22:54:31 2001
+++ drivers/scsi/aic7xxx/aic7xxx_linux.c Thu Dec 13 12:38:30 2001
@@ -1699,6 +1699,7 @@
cmd->request_buffer,
cmd->request_bufflen,
scsi_to_pci_dma_dir(cmd->sc_data_direction));
+ scb->sg_count = 0;
scb->sg_count = ahc_linux_map_seg(ahc, scb,
sg, addr,
cmd->request_bufflen);


2001-12-13 20:58:04

by Justin T. Gibbs

[permalink] [raw]
Subject: Re: that stupid aic7xxx AHC_NSEGS bug

>
>We simply forget to initialize scb->sg_count in the non use_sg
>case, so if the previous usage of that scb has sg_count==AHC_NSEGS
>then we'd hit that panic erroneously. Here is the fix below.

Which just goes to show you have useful Steve Lord's report was.
Even someone unfamiliar with the driver could figure this out once
someone bothered to provide decend debuggin info.

>"It can't possibly be my driver, something broke in some Linux
>subsystem which is making my driver break", sheesh get over it
>Justin...

That's a bit unfair David, and its also not an acurate quote. I
did say to Nick Pasich, "I guarantee you though, it is not the aic7xxx
driver's fault" on 11/26, but ever since it became apparent that
I was wrong (11/29 perhaps?), I've been working with Nick to try
and reproduce the problem. We all make mistakes David, even you.
Get over it. 8-)

--
Justin

2001-12-13 21:10:44

by David Miller

[permalink] [raw]
Subject: Re: that stupid aic7xxx AHC_NSEGS bug

From: "Justin T. Gibbs" <[email protected]>
Date: Thu, 13 Dec 2001 13:57:43 -0700

We all make mistakes David, even you.

Some of us are just a little bit more of a pain in the ass about it,
and this was my point.

2001-12-13 21:13:24

by Justin T. Gibbs

[permalink] [raw]
Subject: Re: that stupid aic7xxx AHC_NSEGS bug

> From: "Justin T. Gibbs" <[email protected]>
> Date: Thu, 13 Dec 2001 13:57:43 -0700
>
> We all make mistakes David, even you.
>
>Some of us are just a little bit more of a pain in the ass about it,
>and this was my point.

Well, you made it brilliantly. Bravo!

--
Justin