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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Robin Murphy <robin.murphy@arm.com>,
	Christian Benvenuti <benve@cisco.com>,
	Nelson Escobar <neescoba@cisco.com>
Cc: linux-rdma@vger.kernel.org, iommu@lists.linux-foundation.org,
	umalhi@cisco.com, Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [bug report] IB/usnic: Add Cisco VIC low-level hardware driver
Date: Mon, 5 Jul 2021 12:21:38 -0300	[thread overview]
Message-ID: <20210705152138.GH4604@ziepe.ca> (raw)
In-Reply-To: <0b8a876b-f71d-24a2-1826-07aa54248f40@arm.com>

On Mon, Jul 05, 2021 at 02:47:36PM +0100, Robin Murphy wrote:
> On 2021-07-05 11:23, Dan Carpenter wrote:
> > [ Ancient code, but the bug seems real enough still.  -dan ]
> > 
> > Hello Upinder Malhi,
> > 
> > The patch e3cf00d0a87f: "IB/usnic: Add Cisco VIC low-level hardware
> > driver" from Sep 10, 2013, leads to the following static checker
> > warning:
> > 
> > 	drivers/iommu/iommu.c:2482 iommu_map()
> > 	warn: sleeping in atomic context
> > 
> > drivers/infiniband/hw/usnic/usnic_uiom.c
> >     244  static int usnic_uiom_map_sorted_intervals(struct list_head *intervals,
> >     245                                                  struct usnic_uiom_reg *uiomr)
> > 
> > This function is always called from usnic_uiom_reg_get() which is holding
> > spin_lock(&pd->lock); so it can't sleep.
> 
> FWIW back in those days it wasn't really well defined whether iommu_map()
> was callable from non-sleeping contexts (the arch/arm DMA API code relied on
> it, for instance). It was only formalised 2 years ago by 781ca2de89ba
> ("iommu: Add gfp parameter to iommu_ops::map") which introduced the
> might_sleep() check that's firing there. I guess these calls want to be
> updated to iommu_map_atomic() now.

Does this mean this driver doesn't work at all upstream? I would be
quite interested to delete it.

Jason
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WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Robin Murphy <robin.murphy@arm.com>,
	Christian Benvenuti <benve@cisco.com>,
	Nelson Escobar <neescoba@cisco.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
	umalhi@cisco.com, linux-rdma@vger.kernel.org,
	iommu@lists.linux-foundation.org
Subject: Re: [bug report] IB/usnic: Add Cisco VIC low-level hardware driver
Date: Mon, 5 Jul 2021 12:21:38 -0300	[thread overview]
Message-ID: <20210705152138.GH4604@ziepe.ca> (raw)
In-Reply-To: <0b8a876b-f71d-24a2-1826-07aa54248f40@arm.com>

On Mon, Jul 05, 2021 at 02:47:36PM +0100, Robin Murphy wrote:
> On 2021-07-05 11:23, Dan Carpenter wrote:
> > [ Ancient code, but the bug seems real enough still.  -dan ]
> > 
> > Hello Upinder Malhi,
> > 
> > The patch e3cf00d0a87f: "IB/usnic: Add Cisco VIC low-level hardware
> > driver" from Sep 10, 2013, leads to the following static checker
> > warning:
> > 
> > 	drivers/iommu/iommu.c:2482 iommu_map()
> > 	warn: sleeping in atomic context
> > 
> > drivers/infiniband/hw/usnic/usnic_uiom.c
> >     244  static int usnic_uiom_map_sorted_intervals(struct list_head *intervals,
> >     245                                                  struct usnic_uiom_reg *uiomr)
> > 
> > This function is always called from usnic_uiom_reg_get() which is holding
> > spin_lock(&pd->lock); so it can't sleep.
> 
> FWIW back in those days it wasn't really well defined whether iommu_map()
> was callable from non-sleeping contexts (the arch/arm DMA API code relied on
> it, for instance). It was only formalised 2 years ago by 781ca2de89ba
> ("iommu: Add gfp parameter to iommu_ops::map") which introduced the
> might_sleep() check that's firing there. I guess these calls want to be
> updated to iommu_map_atomic() now.

Does this mean this driver doesn't work at all upstream? I would be
quite interested to delete it.

Jason

  reply	other threads:[~2021-07-05 15:21 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05 10:23 [bug report] IB/usnic: Add Cisco VIC low-level hardware driver Dan Carpenter
2021-07-05 10:23 ` Dan Carpenter
2021-07-05 13:47 ` Robin Murphy
2021-07-05 13:47   ` Robin Murphy
2021-07-05 15:21   ` Jason Gunthorpe [this message]
2021-07-05 15:21     ` Jason Gunthorpe
2021-07-05 15:39     ` Robin Murphy
2021-07-05 15:39       ` Robin Murphy
2021-07-05 15:45     ` Dan Carpenter
2021-07-05 15:45       ` Dan Carpenter
  -- strict thread matches above, loose matches on Subject: below --
2021-08-04  9:08 Dan Carpenter
2017-10-12 12:57 Dan Carpenter

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