Re: [PATCH V4 net-bugfixs] net/ethernet: Update ret when ptp_clock is ERROR

On 12/11/2020 10:25, Arnd Bergmann wrote:

On Thu, Nov 12, 2020 at 2:48 AM 王擎 [off-list ref] wrote:

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On Wed, Nov 11, 2020 at 03:24:33PM +0200, Grygorii Strashko wrote:

I don't think v1 builds cleanly folks (not 100% sure, cpts is not
compiled on x86):

               ret = cpts->ptp_clock ? cpts->ptp_clock : (-ENODEV);

ptp_clock is a pointer, ret is an integer, right?

yeah, I will modify like: ret = cpts->ptp_clock ? PTR_ERR(cpts->ptp_clock) : -ENODEV;

This is not really getting any better. If Richard is worried about
Kconfig getting changed here, I would suggest handling the
case of PTP being disabled by returning an error early on in the
function, like

struct am65_cpts *am65_cpts_create(struct device *dev, void __iomem *regs,
                                    struct device_node *node)
{
         struct am65_cpts *cpts;
         int ret, i;

         if (!IS_ENABLED(CONFIG_PTP_1588_CLOCK))
                  return -ENODEV;

Then you can replace the broken IS_ERR_OR_NULL() path with
a simpler IS_ERR() case and keep the rest of the function readable.

There is proper blocker in am65-cpts.h #if IS_ENABLED(CONFIG_TI_K3_AM65_CPTS)
and in Makefile and proper dependency in Kconfig.

config TI_K3_AM65_CPTS
	tristate "TI K3 AM65x CPTS"
	depends on ARCH_K3 && OF
	depends on PTP_1588_CLOCK

But, as Richard mentioned [1], ptp_clock_register() may return NULL even if PTP_1588_CLOCK=y
(which I can't confirm neither deny - from the fast look at ptp_clock_register()
  code it seems should not return NULL)

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Grygorii, would you mind sending a correct patch in so Wang Qing can
see how it's done? I've been asking for a fixes tag multiple times
already :(

I still don't quite understand what a fixes tag means，
can you tell me how to do this, thanks.

This identifies which patch introduced the problem you are fixing
originally. If you add an alias in your ~/.gitconfig such as

[alias]
         fixes = show --format='Fixes: %h (\"%s\")' -s

then running

$ git fixes f6bd59526c
produces this line:

Fixes: f6bd59526ca5 ("net: ethernet: ti: introduce am654 common
platform time sync driver")

correct

which you can add to the changelog, just above the Signed-off-by
lines.

[1] https://lore.kernel.org/patchwork/patch/1334067/#1529232
-- 
Best regards,
grygorii