Re: crypto: hisilicon - Fix warning on printing %p with dma_addr_t

On 2019/8/16 15:08, Ondrej Mosnáček wrote:

pi 16. 8. 2019 o 9:02 Ondrej Mosnáček [off-list ref] napísal(a):

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Hi Herbert,

pi 16. 8. 2019 o 1:52 Herbert Xu [off-list ref] napísal(a):

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On Thu, Aug 15, 2019 at 10:17:37PM +0800, Zhou Wang wrote:

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-   dev_dbg(&qm->pdev->dev, "QM mailbox request to q%u: %u-%pad\n", queue,
-           cmd, dma_addr);
+   dev_dbg(&qm->pdev->dev, "QM mailbox request to q%u: %u-%#lxad\n",
+           queue, cmd, (unsigned long)dma_addr);

Thanks. However, to be honest I can't get why we fix it like this.
Can you give me a clue?

dma_addr_t is not a pointer.  It's an integer type and therefore
you need to print it out as such.

According to Documentation/core-api/printk-formats.rst, %pad is the
format specifier intended specifically for dma_addr_t [1], so perhaps
the kbuild robot warning was in fact bogus?

[1] https://www.kernel.org/doc/html/latest/core-api/printk-formats.html#dma-address-types-dma-addr-t

Oh, wait, in that section it actually says "Passed by reference.", so
Zhou is most likely right that the proper fix is to pass a pointer to
the variable containing the address (I assume this is to make the
generic GCC's format checking pass even if dma_addr_t is not actually
a pointer).

Yes, I think you are right, I also mentioned this in v3.

Thanks,
Zhou

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Actually my patch is buggy too, on some architectures it can be
a long long so we need to cast is such.

Cheers,
--
Email: Herbert Xu [off-list ref]
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt