x86/platform/intel-mid: Revert "Make 'bt_sfi_data' const"

The annoying static analyzer follow up patches sometimes make a pain rather than fixing issues.

The one done by commit 276c87054751

("x86/platform/intel-mid: Make 'bt_sfi_data' const")

convert the struct to be const while it is used as a temporary container for important data that is used to fill 'parent' and 'name' fields in struct platform_device_info.

That's why revert the commit which had been apparently done w/o reading the code.

Note, compiler doesn't notice this due to explicit cast, which would be addressed separately.

---
v2: low the tone of accusation that this made a regression

 arch/x86/platform/intel-mid/device_libs/platform_bt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index dc036e511f48..5a0483e7bf66 100644
@@ -60,7 +60,7 @@ static int __init tng_bt_sfi_setup(struct bt_sfi_data *ddata)
 	return 0;
 }
 
-static const struct bt_sfi_data tng_bt_sfi_data __initdata = {
+static struct bt_sfi_data tng_bt_sfi_data __initdata = {
 	.setup	= tng_bt_sfi_setup,
 };
 

2.15.1

BTW., don't worry about that aspect too much: after a long debugging session it's pretty natural to be upset at whoever introduced a regression.

( In fact a number of times I too got upset at the moron who wrote a particular
piece of buggy code, only for 'git annotate' to remind me that the moron was me. )

I personally just ignore the emotional attributes, and I usually edit changelogs accordingly as well so the temporary state of mind of finding a regression doesn't trickle upstream.

Plus in this particular case if we can help type propagation for driver data to become a bit cleaner then the kernel project has gained a bit through all this pain.

Thanks,

Ingo

It appears that regression has been introduced by a new dependency to the hci_bcm.c.

In any case, can we apply this one to 4.15 cycle to make others prevent do an actual regressions further:

commit 03838ae1e8f692dd2bdbd49820ed668d4b7bfbc2

Author: Andi Kleen <[email protected]>
Date:   Fri Jan 5 13:26:44 2018 +1100

arch/x86/platform/intel-mid/device_libs/platform_bt.c: fix const
confusion

I has been thinking if 0day can complain about these:
1) castings in new code
2) applying const to older *working* code

Fengguang, what do you think?

Andy Shevchenko <[email protected]>
Intel Finland Oy

As suggested previously, I think it would be better if code that retrieves const structures from nonconst fields would store the result in a const variable. Then the compiler would pick up the verification from there. A Coccinelle script can detect cases where this property does not hold, at least within a single file. This would have protected the given code and still allowed constant structures to be made const.

julia

Thank you!

Andy Shevchenko <[email protected]>
Intel Finland Oy