linuxkpi: Add a few wait_bit functions

[manu]

Summary

The linux function does a lot more than that as multiple waitqueue could be fetch
from a static table based on the hash of the argument but since in DRM it's only used
in one place just add a single variable.
We will probably need to change that in the futur but it's ok with DRM even with current
linux.

Sponsored-by: The FreeBSD Foundation

[• hselasky]

sys/compat/linuxkpi/common/src/linux_compat.c

2495

Declare both of these in waitbit.h and include this header file instead of duplicating the extern declarations.

[• hselasky]

sys/compat/linuxkpi/common/src/linux_schedule.c

365

What about moving these simple declarations to waitbit.h as static inline functions?

[manu]

Address hselasky@'s comments.

[• hselasky]

sys/compat/linuxkpi/common/src/linux_compat.c

89

#include <linux/waitbit.h>

Here ??

[manu]

sys/compat/linuxkpi/common/src/linux_compat.c

89

Why ? it's not needed

[• hselasky]

sys/compat/linuxkpi/common/src/linux_compat.c

89

Are you sure you have the prototype for those wait queues declared?

[manu]

sys/compat/linuxkpi/common/src/linux_compat.c

89

Yes

[• hselasky]

Which header file does linux_compat.c include that includes wait_bit.h , I cannot see it?

[manu]

In D26054#578431, @hselasky wrote:

Which header file does linux_compat.c include that includes wait_bit.h , I cannot see it?

Why do you want it to include wait_bit.h ? It doesn't uses any function from there.

[• hselasky]

Hi, In wait_bit.h you have the prototypes:

extern wait_queue_head_t linux_bit_waitq;
extern wait_queue_head_t linux_var_waitq;

For:

wait_queue_head_t linux_bit_waitq;
wait_queue_head_t linux_var_waitq;

Even though the module compiles, I think it is most correct to have the extern's included before the declarations!

sys/compat/linuxkpi/common/src/linux_schedule.c

43

You can remove this include I guess.

[manu]

sys/compat/linuxkpi/common/src/linux_schedule.c

43

True, this one is a leftover.

[manu]

Include wait_bit.h in compat.c, remove wait_bit.h from schedule.c

[• hselasky]

Don't forget the put the word LinuxKPI in the commit message and MFC after.