Am Montag, 14. November 2016, 15:19:28 CET schrieb Bjorn Helgaas:
> [+cc Shawn, Heiko, Michal, Soren, Bharat, Rob H, Frank, devicetree@vger]
>
> On Sat, Nov 12, 2016 at 12:39:01PM +0530, Kishon Vijay Abraham I wrote:
> > Hi,
> >
> > On Saturday 12 November 2016 03:08 AM, Bjorn Helgaas wrote:
> > > On Mon, Oct 17, 2016 at 02:54:37PM +0000, Wei Yongjun wrote:
> > >> From: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
> > >>
> > >> This node pointer is returned by of_get_next_child() with refcount
> > >> incremented in this function. of_node_put() on it before exitting
> > >> this function on error.
> > >>
> > >> This is detected by Coccinelle semantic patch.
> > >>
> > >> Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
> > >
> > > Kishon, this looks correct to me, so I applied it to pci/host-dra7xx for
> > > v4.10. Let me know if you have any issue with it.
> > >
> > >> ---
> > >>
> > >> drivers/pci/host/pci-dra7xx.c | 1 +
> > >> 1 file changed, 1 insertion(+)
> > >>
> > >> diff --git a/drivers/pci/host/pci-dra7xx.c
> > >> b/drivers/pci/host/pci-dra7xx.c
> > >> index 9595fad..79297e9 100644
> > >> --- a/drivers/pci/host/pci-dra7xx.c
> > >> +++ b/drivers/pci/host/pci-dra7xx.c
> > >> @@ -177,6 +177,7 @@ static int dra7xx_pcie_init_irq_domain(struct
> > >> pcie_port *pp)> >>
> > >> &intx_domain_ops, pp);
> > >>
> > >> if (!pp->irq_domain) {
> > >>
> > >> dev_err(dev, "Failed to get a INTx IRQ domain\n");
> > >>
> > >> + of_node_put(pcie_intc_node);
> >
> > I think of_node_put should be used for both the error case and non-error
> > case.
> Hmm, OK. I don't know what the rules are. Certainly if we made these
> drivers modular, I don't think we'd want to leak these references
> every time we unload/reload the module. Should we do the put
> immediately here, or in the module remove path, or ...?
>
> Adding other driver and DT folks for comment.
I think the function above (dra7xx_pcie_init_irq_domain) can do the
of_node_put at its end in all cases as suggested by Kishon.
of_get_next_child() will increment the refcount
irq_domain_add_linear()
__irq_domain_add() also increments the refcount
irq_domain_remove() will decrement the refcount
So it should be safe to decrement the refcount in
dra7xx_pcie_init_irq_domain() in all cases as the irq-domain internals will
always keep it above 1 as long as the node is used.
Heiko
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