Re: Linux 2.6.20-rc1

[Jens Axboe <jens.axboe@oracle.com>]

On Thu, Dec 14 2006, Alistair John Strachan wrote:
> On Thursday 14 December 2006 21:50, Jeff Garzik wrote:
> > Alistair John Strachan wrote:
> > > Before I proceed with the horrors of an -rc1 bisection, could somebody
> > > send me the ADMA patches so I can eliminate those first?
> >
> > Run
> >
> > 	git-whatchanged drivers/ata/sata_nv.c
> >
> > and that will give you a list of recent changes.  To obtain the "diff
> > -u" patch for a single commit, run
> >
> > 	git-diff-tree -p $SHA_HASH > /tmp/patch
> 
> I used a variation on this:
> 
> 	git-whatchanged -p v2.6.19.. drivers/ata/sata_nv.c >sata_nv
> 
> Reverted it (against v2.6.20-rc1), compiled that kernel, no dice.
> 
> [root] 22:32 [~] hddtemp /dev/sda
> /dev/sda: ATA WDC WD2500KS-00M: S.M.A.R.T. not available
> 
> I'll start the bisection.

Just noticed that most of the mails I wrote on this thread were
apparently without linux-kernel cc'ed (dunno who removed the cc). So
I'll write a small summary - the problem is that hddtemp includes some
fragile code to check the sense info, and this commit:

http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=f38621b3109068adc8430bc2d170ccea59df4261

broke it. hddtemp expects 14, but it now sees 12. IMHO hddtemp is buggy
and should be fixed, the best option is simply to kill the sense checks
as I think they have little (if any) value. Patch below for that.

So the problem was never the SG_IO changes, the fact that somebody
noticed the same thing in bugzilla for a 2.6.19-rc6-mm kernel backs that
up.

--- hddtemp-0.3-beta15/src/satacmds.c~	2006-12-19 12:01:10.000000000 +0100
+++ hddtemp-0.3-beta15/src/satacmds.c	2006-12-19 12:01:27.000000000 +0100
@@ -54,7 +54,6 @@
   unsigned char cdb[16];
   unsigned char sense[32];
   int dxfer_direction;
-  int ret;
   
   memset(cdb, 0, sizeof(cdb));
   cdb[0] = ATA_16;
@@ -78,13 +77,7 @@
     cdb[6] = cmd[1];
   cdb[14] = cmd[0];
 
-  ret = scsi_SG_IO(device, cdb, sizeof(cdb), buffer, cmd[3] * 512, sense, sizeof(sense), dxfer_direction);
- 
-  /* Verify SATA magics */
-  if (sense[0] != 0x72 || sense[7] != 0x0e || sense[9] != 0x0e || sense[10] != 0x00)
-    return 1;		  
-  else 
-    return ret;
+  return scsi_SG_IO(device, cdb, sizeof(cdb), buffer, cmd[3] * 512, sense, sizeof(sense), dxfer_direction);
 }
 
 void sata_fixstring(unsigned char *s, int bytecount)

-- 
Jens Axboe