Bug#411499: kernel: panic with scsi scanner and aha1542

[Moritz Muehlenhoff <jmm@inutil.org>]

On Sat, Jun 06, 2009 at 07:33:22PM +0100, Ben Hutchings wrote:
> The panic is due to the driver receiving a request to transfer 5 bytes
> when it requires and checks for even lengths.  It was almost certainly
> introduced by this change between 2.6.15 and .16:
> 
> commit eca7be5e1899626db01ae42b0123458d6fb34930
> Author: Brian King <brking@us.ibm.com>
> Date:   Tue Feb 14 12:42:24 2006 -0600
> 
>     [SCSI] sg: Remove aha1542 hack
>     
>     Remove a hack in the sg driver that alters the total buffer
>     length for SG_IO commands to ensure buffers are not odd byte
>     lengths. This breaks on the ipr driver since it requires the
>     request_bufflen to equal the length specified in the cdb.
>     The block layer SG_IO code does not appear to have this hack.
>     
>     Signed-off-by: Douglas Gilbert <dougg@torque.net>
>     Signed-off-by: Brian King <brking@us.ibm.com>
>     Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
> 
> A later change between 2.6.23 and .24 removed the check for even lengths
> from aha1542:
> 
> commit fc3fdfcc8bb0e069a2d172e745664fa2c1f1b0ca
> Author: Boaz Harrosh <bharrosh@panasas.com>
> Date:   Sun Sep 9 21:02:45 2007 +0300
> 
>     [SCSI] aha1542: convert to accessors and !use_sg cleanup
>     
>      - convert to accessors and !use_sg cleanup
>     
>     Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
>     Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
> 
> but it's not clear that the driver will work correctly with odd lengths.

JJL, sz-pr,
does the scanner work properly in current kernels?

Cheers,
        Moritz