Re: Problem with usb-storage using HP 8200 external CD-ROM burner

[Brent Baccala <baccala@freesoft.org>]

Matthew Dharm wrote:
> 
> Brent --
> 
> As the module maintainer, I'm very intereted in your analysis.....
> 
> Of course, I'm interested in knowing how the command_abort function can be
> made safe -- I think there are already patches in the 2.4.8 kernel which
> should fix the cause of this function getting called.
> 
> Any ideas on how to fix this issue?

Well, what comes to mind immediately is two things.

First, does scsiglue.c's abort_command really need to handshake with the
code in usb.c?  If not, just get rid of the down and its matching up.

Second, this code (in scsi_error.c):

      774         spin_lock_irqsave(&io_request_lock, flags);
      775         rtn = SCpnt->host->hostt->eh_abort_handler(SCpnt);
      776         spin_unlock_irqrestore(&io_request_lock, flags);

seems like a real shotgun approach.  Get rid of the spinlock stuff, and
make sure that the abort handlers lock io_request_lock themselves if
they need it.  Of course, this would require changes to all the scsi
drivers.

I don't work with the kernel that much, so really I'm hoping somebody
else can suggest the fix - that's why I posted it in the first place. 
I'll cc this to the mailing lists, in the hope that somebody will have
an idea.

-- 
                                        -bwb

                                        Brent Baccala
                                        baccala@freesoft.org

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