linux-kernel - Re: iommu_iova leak [inside 3w-9xxx]

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Date:	Sun, 18 Sep 2011 18:56:20 +0400
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	Chris Boot <bootc@...tc.net>
Cc:	"Woodhouse, David" <david.woodhouse@...el.com>,
	adam radford <aradford@...il.com>,
	lkml <linux-kernel@...r.kernel.org>,
	Adam Radford <linuxraid@....com>,
	"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>
Subject: Re: iommu_iova leak [inside 3w-9xxx]

On Sun, 2011-09-18 at 18:25 +0400, James Bottomley wrote:
> On Sun, 2011-09-18 at 15:05 +0100, Chris Boot wrote: 
> > > Hardly ... all it's saying is that twa_exit doesn't wait for pending I/O
> > > to complete, so when you remove the module it tears down in the middle
> > > of an I/O.  A bug, yes, but it's not indicative of any sort of leak in
> > > the maps/unmaps.
> > 
> > 
> > James,
> > 
> > I don't think that's the case - I had unmounted all filesystems, deactivated all volume groups, and performed a sync before waiting a few seconds and running rmmod. Next time I'll also 'echo 1 > /sys/block/sdX/device/delete' if that's helpful.
> 
> Actually, I take all that back: the driver has a bug in QUEUE_FULL
> handling: twa_scsi_queue() calls twa_scsiop_execute_scsi(), which maps
> the dma buffer, but if the card responds QUEUE_FULL it just returns
> SCSI_MLQUEUE_HOST_BUSY without ever unmapping.  That leg in the code
> frees the request but also doesn't unmap it.  In fact any error return
> from twa_scsiop_execute_scsi() seems to have the same problem (but
> QUEUE_FULL is the only silent one).
> 
> I trust Adam will fix this.

Actually, while Adam's mulling this, try the following.  It should at
least confirm we're on the right track.

James

---

diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index b7bd5b0..3868ab2 100644
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -1800,10 +1800,12 @@ static int twa_scsi_queue_lck(struct scsi_cmnd *SCpnt, void (*done)(struct scsi_
 	switch (retval) {
 	case SCSI_MLQUEUE_HOST_BUSY:
 		twa_free_request_id(tw_dev, request_id);
+		twa_unmap_scsi_data(tw_dev, request_id);
 		break;
 	case 1:
 		tw_dev->state[request_id] = TW_S_COMPLETED;
 		twa_free_request_id(tw_dev, request_id);
+		twa_unmap_scsi_data(tw_dev, request_id);
 		SCpnt->result = (DID_ERROR << 16);
 		done(SCpnt);
 		retval = 0;


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