build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

[Sudip Mukherjee (Codethink)]

Hi All,

Not sure if it has been reported, builds of alpha, csky, xtensa, riscv, s390 allmodsconfig
have failed to build next-20220718 with the error:


drivers/pci/controller/dwc/pci-imx6.c:973:13: error: 'imx6_pcie_host_exit' defined but not used [-Werror=unused-function]
  973 | static void imx6_pcie_host_exit(struct dw_pcie_rp *pp)
      |             ^~~~~~~~~~~~~~~~~~~
drivers/pci/controller/dwc/pci-imx6.c:904:13: error: 'imx6_pcie_stop_link' defined but not used [-Werror=unused-function]
  904 | static void imx6_pcie_stop_link(struct dw_pcie *pci)
      |             ^~~~~~~~~~~~~~~~~~~


--
Regards
Sudip

Re: build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

[Arnd Bergmann]

On Mon, Jul 18, 2022 at 1:58 PM Sudip Mukherjee (Codethink)
<sudipm.mukherjee@gmail.com> wrote:
>
> Hi All,
>
> Not sure if it has been reported, builds of alpha, csky, xtensa, riscv, s390 allmodsconfig
> have failed to build next-20220718 with the error:
>
>
> drivers/pci/controller/dwc/pci-imx6.c:973:13: error: 'imx6_pcie_host_exit' defined but not used [-Werror=unused-function]
>   973 | static void imx6_pcie_host_exit(struct dw_pcie_rp *pp)
>       |             ^~~~~~~~~~~~~~~~~~~
> drivers/pci/controller/dwc/pci-imx6.c:904:13: error: 'imx6_pcie_stop_link' defined but not used [-Werror=unused-function]
>   904 | static void imx6_pcie_stop_link(struct dw_pcie *pci)
>       |             ^~~~~~~~~~~~~~~~~~~
>

These are called from inside an "#ifdef CONFIG_PM_SLEEP" section. The best
fix is to remove the #ifdef and replace SET_NOIRQ_SYSTEM_SLEEP_PM_OPS()
with the new simpler NOIRQ_SYSTEM_SLEEP_PM_OPS().

          Arnd

Re: build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

[Bjorn Helgaas]

On Mon, Jul 18, 2022 at 02:42:16PM +0200, Arnd Bergmann wrote:
> On Mon, Jul 18, 2022 at 1:58 PM Sudip Mukherjee (Codethink)
> <sudipm.mukherjee@gmail.com> wrote:
> >
> > Hi All,
> >
> > Not sure if it has been reported, builds of alpha, csky, xtensa, riscv, s390 allmodsconfig
> > have failed to build next-20220718 with the error:
> >
> >
> > drivers/pci/controller/dwc/pci-imx6.c:973:13: error: 'imx6_pcie_host_exit' defined but not used [-Werror=unused-function]
> >   973 | static void imx6_pcie_host_exit(struct dw_pcie_rp *pp)
> >       |             ^~~~~~~~~~~~~~~~~~~
> > drivers/pci/controller/dwc/pci-imx6.c:904:13: error: 'imx6_pcie_stop_link' defined but not used [-Werror=unused-function]
> >   904 | static void imx6_pcie_stop_link(struct dw_pcie *pci)
> >       |             ^~~~~~~~~~~~~~~~~~~
> >
> 
> These are called from inside an "#ifdef CONFIG_PM_SLEEP" section. The best
> fix is to remove the #ifdef and replace SET_NOIRQ_SYSTEM_SLEEP_PM_OPS()
> with the new simpler NOIRQ_SYSTEM_SLEEP_PM_OPS().

Might be simpler, but wow, it's hard to keep up with all the
permutations of sleep ops ;)

Unfortunately 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros,
deprecate old ones"), which added NOIRQ_SYSTEM_SLEEP_PM_OPS, didn't
add any hints near SET_NOIRQ_SYSTEM_SLEEP_PM_OPS.

We have several PCI controller drivers that use the "#ifdef
CONFIG_PM_SLEEP" and SET_NOIRQ_SYSTEM_SLEEP_PM_OPS pattern or the
"__maybe_unused" + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS pattern.  I guess we
need to look at all of them and figure out the best practice.

Bjorn

Re: build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

[Arnd Bergmann]

On Mon, Jul 18, 2022 at 6:14 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> On Mon, Jul 18, 2022 at 02:42:16PM +0200, Arnd Bergmann wrote:
>
> Might be simpler, but wow, it's hard to keep up with all the
> permutations of sleep ops ;)
>
> Unfortunately 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros,
> deprecate old ones"), which added NOIRQ_SYSTEM_SLEEP_PM_OPS, didn't
> add any hints near SET_NOIRQ_SYSTEM_SLEEP_PM_OPS.
>
> We have several PCI controller drivers that use the "#ifdef
> CONFIG_PM_SLEEP" and SET_NOIRQ_SYSTEM_SLEEP_PM_OPS pattern or the
> "__maybe_unused" + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS pattern.  I guess we
> need to look at all of them and figure out the best practice.

Yes, this is a larger effort. It's been under discussion for many years until we
could agree on a nicer way to handle this and avoid both the #ifdef  and the
__maybe_unused annotations. There are hundreds of drivers using the older
patterns, and I think there is an effort to address them one subsystem
at a time,
whenever someone finds the time.

       Arnd

Re: build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

[Bjorn Helgaas]

On Mon, Jul 18, 2022 at 12:58:05PM +0100, Sudip Mukherjee (Codethink) wrote:
> Hi All,
> 
> Not sure if it has been reported, builds of alpha, csky, xtensa, riscv, s390 allmodsconfig
> have failed to build next-20220718 with the error:
> 
> 
> drivers/pci/controller/dwc/pci-imx6.c:973:13: error: 'imx6_pcie_host_exit' defined but not used [-Werror=unused-function]
>   973 | static void imx6_pcie_host_exit(struct dw_pcie_rp *pp)
>       |             ^~~~~~~~~~~~~~~~~~~
> drivers/pci/controller/dwc/pci-imx6.c:904:13: error: 'imx6_pcie_stop_link' defined but not used [-Werror=unused-function]
>   904 | static void imx6_pcie_stop_link(struct dw_pcie *pci)
>       |             ^~~~~~~~~~~~~~~~~~~

Thanks for the report!  I propose the following patch, which I have
tentatively applied to my pci/ctrl/imx6 branch:


commit 0e4daeaa52ca ("PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()")
Author: Bjorn Helgaas <bhelgaas@google.com>
Date:   Tue Jul 19 15:50:18 2022 -0500

    PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()
    
    Replace SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() with NOIRQ_SYSTEM_SLEEP_PM_OPS(),
    which has the advantage that the compiler always sees the PM callbacks as
    referenced, so they don't need to be wrapped with "#ifdef CONFIG_PM_SLEEP"
    or tagged with "__maybe_unused" to avoid "defined but not used" warnings.
    
    See 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros, deprecate old ones").
    
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 5ea01ed4674d..6f1dfbfc4304 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -884,7 +884,6 @@ static const struct dw_pcie_ops dw_pcie_ops = {
 	.start_link = imx6_pcie_start_link,
 };
 
-#ifdef CONFIG_PM_SLEEP
 static void imx6_pcie_ltssm_disable(struct device *dev)
 {
 	struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
@@ -1008,11 +1007,10 @@ static int imx6_pcie_resume_noirq(struct device *dev)
 
 	return 0;
 }
-#endif
 
 static const struct dev_pm_ops imx6_pcie_pm_ops = {
-	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend_noirq,
-				      imx6_pcie_resume_noirq)
+	NOIRQ_SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend_noirq,
+				  imx6_pcie_resume_noirq)
 };
 
 static int imx6_pcie_probe(struct platform_device *pdev)

Re: build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

[Arnd Bergmann]

On Tue, Jul 19, 2022 at 11:04 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> commit 0e4daeaa52ca ("PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()")
> Author: Bjorn Helgaas <bhelgaas@google.com>
> Date:   Tue Jul 19 15:50:18 2022 -0500
>
>     PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()
>
>     Replace SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() with NOIRQ_SYSTEM_SLEEP_PM_OPS(),
>     which has the advantage that the compiler always sees the PM callbacks as
>     referenced, so they don't need to be wrapped with "#ifdef CONFIG_PM_SLEEP"
>     or tagged with "__maybe_unused" to avoid "defined but not used" warnings.
>
>     See 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros, deprecate old ones").
>
>     Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Re: build failure of next-20220718 due to 'imx6_pcie_host_exit' defined but not used

[Bjorn Helgaas]

On Tue, Jul 19, 2022 at 11:16:40PM +0200, Arnd Bergmann wrote:
> On Tue, Jul 19, 2022 at 11:04 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> >
> > commit 0e4daeaa52ca ("PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()")
> > Author: Bjorn Helgaas <bhelgaas@google.com>
> > Date:   Tue Jul 19 15:50:18 2022 -0500
> >
> >     PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()
> >
> >     Replace SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() with NOIRQ_SYSTEM_SLEEP_PM_OPS(),
> >     which has the advantage that the compiler always sees the PM callbacks as
> >     referenced, so they don't need to be wrapped with "#ifdef CONFIG_PM_SLEEP"
> >     or tagged with "__maybe_unused" to avoid "defined but not used" warnings.
> >
> >     See 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros, deprecate old ones").
> >
> >     Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> 
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Thanks!  And sorry about being crabby earlier.  If this allows us to
get rid of those #ifdefs and __maybe_unused, it's a great improvement!

Bjorn