On Wed, Jul 23, 2014 at 11:19 AM, <scame...@beardog.cce.hp.com> wrote: > On Wed, Jul 23, 2014 at 08:11:33AM -0700, Randy Dunlap wrote: >> On 07/23/2014 07:41 AM, scame...@beardog.cce.hp.com wrote: >> > On Wed, Jul 23, 2014 at 02:15:29PM +0000, Benesh, Scott wrote: >> >> From: Nick Krause [mailto:xerofo...@gmail.com] >> >> Sent: Saturday, July 19, 2014 11:51 PM >> >> To: mike.mil...@hp.com >> >> Cc: ISS StorageDev; linux-kernel@vger.kernel.org >> >> Subject: cciss_scsi.c: Fix me >> >> >> >> Hey Mike, >> >> I seem to be hitting a fix me message in this file in >> >> function,cciss_scsi_queue_command_lck. >> >> I am wondering what you want to do when C is Null? >> >> Cheers Nick >> > >> > Hi Nick, >> > >> > Mike's moved on from HP to Canonical now. >> > >> > It looks like you're running out of commands for tape drives, >> > which shouldn't ever happen, since we set >> > >> > sh->can_queue = cciss_tape_cmds; >> > >> > and we allocate that many commands + 2.... >> > >> > scsi_cmd_stack_setup(ctlr_info_t *h, struct cciss_scsi_adapter_data_t *sa) >> > { >> > int i; >> > struct cciss_scsi_cmd_stack_t *stk; >> > size_t size; >> > >> > stk = &sa->cmd_stack; >> > stk->nelems = cciss_tape_cmds + 2; >> > >> > You're apparently hitting this: >> > >> > spin_lock_irqsave(&h->lock, flags); >> > c = scsi_cmd_alloc(h); >> > spin_unlock_irqrestore(&h->lock, flags); >> > if (c == NULL) { /* trouble... */ >> > dev_warn(&h->pdev->dev, "scsi_cmd_alloc returned NULL!\n"); >> > /* FIXME: next 3 lines are -> BAD! <- */ >> > cmd->result = DID_NO_CONNECT << 16; >> > done(cmd); >> > return 0; >> > } >> > >> > which means that scsi_cmd_alloc returned NULL, which only happens >> > if the thing has run out of commands. >> > >> > It's not obvious to me how it can be that it runs out of commands. >> > Maybe we're losing them somehow, but this has not previously been >> > a problem that I'm aware of. >> > >> > Are you able to reproduce the problem? >> > >> > What's going on on the system when it happens? >> > >> > putting in a dump_stack(); near that FIXME might give a clue. >> > >> > Which kernel are you running? >> > >> > -- steve >> >> Hi Steve, >> >> You apparently have not been following the Nick saga. >> >> Nick is using cscope to search for FIXMEs in the kernel source tree and >> then trying to generate patches to remove or 'fix' them. >> >> He is not hitting a kernel oops or panic or bug. > > Ah, ok, thanks. That explains it, because I was pretty sure that > code is a "this will never happen" case. > > -- steve >
Fine I give up you guys don't want me to touch these fix mes and leave them alone. Cheers Nick -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
