On Wed, Mar 15, 2017 at 12:12:48PM +0100, Bjørn Mork wrote:
> Alexander Kapshuk <alexander.kapshuk@xxxxxxxxx> writes:
>
> >>> On Wed, Mar 15, 2017 at 10:31 AM, Tobin C. Harding <me@xxxxxxxx> wrote:
> >>> > why does calling pr_debug() with more than one argument cause a sparse
> >>> > warning?
> >>> >
> >>> > drivers/mmc/core/sdio_io.c:70:9: error: unknown field name in initializer
> >>> >
> >>> > sdio_io.c:70:
> >>> > pr_debug("SDIO: Enabling device %s...\n", sdio_func_id(func));
> ..
> > 'sdio_func_id()' is a macro defined here:
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/include/linux/mmc/sdio_func.h?id=refs/tags/v4.11-rc2
> > #define sdio_func_id(f) (dev_name(&(f)->dev))
>
>
> So the "func" in that debug call contains a 'struct device'. Any
> reason why the pr_debug() shouldn't be converted to something like
>
> dev_dbg(&func->dev, "SDIO: Enabling device...\n");
Good point Bjørn, thanks. And thank you Alexander for your input. I
fear I may have sent you both on a wild goose chase with the example
that I chose. pr_debug() causes a sparse warning in many instances
when the format string includes format specifiers.
/* this is fine */
pr_debug("some info string");
/* this often causes Sparse warning */
pr_debug("string with specifier: %d", foo);
A simple example can be seen by adding this function
void foo(const char *baz)
{
pr_debug("cause Sparse warning - %s\n", baz);
}
To a random driver, and running `make C=2 M=drivers/staging/ks7010`
drivers/staging/ks7010/ks_hostif.c:2702:9: error: unknown field name in initializer
For more examples from the kernel tree, running:
$ make -j9 C=2 M=drivers/staging 2>sparse.out
gives many such cases, for example:
drivers/staging/fbtft/fbtft-core.c:472:17: error: unknown field name in initialize
drivers/staging/media/bcm2048/radio-bcm2048.c:2596:17: error: unknown field name in initializer
drivers/staging/dgnc/dgnc_tty.c:1274:17: error: unknown field name in initializer
Also dev_debug causes the same sparse warning at times, for example:
drivers/staging/comedi/comedi_fops.c:352:17: error: unknown field name in initialize
if (s->busy) {
dev_dbg(dev->class_dev,
"subdevice is busy, cannot resize buffer\n");
return -EBUSY;
}
And 2 more example instances of dev_debug:
drivers/staging/comedi/drivers/das16.c:578:25: error: unknown field name in initialize
drivers/staging/dgnc/dgnc_tty.c:1274:17: error: unknown field name in initializer
thanks,
Tobin.
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