click: Compatibility changes for kernel lock debugging

[kph]

Lock correctness debugging requires that various kernel data structures
be statically allocated, instead of being allocated in dynamic
memory. One such structre is the VFS file_system_type.

Previously, proclikefs imbedded this structure inside its
proclikefs_file_system structure, which was allocated dynamically.
Instead, each client of proclikefs (actually just clickfs) now
statically allocates a file_system_type structure, and registers
this with proclikefs.

The include file semaphore.h contains a C99-style structure
initializer which is not legal in C++. This file only gets
included when spin lock debugging is enabled. Since Click does
not use sema_init(), the simple fix is to skip its compilation
by surrounding it in #ifndef __cplusplus.

The include file semaphore.h is also mangled by the fixincludes.pl
changes which are intended to only modify ktime.h. Limit the scope
of ktime-related changes to only ktime.h

[kohler]

Kevin!!!! Awesome. Some comments:

(1) Can this be split into two commits?
(2) The fixincludes.pl is I think ready to apply immediately.
(3) The proclikefs one is not. I think you're missing the point of proclikefs. The purpose of proclikefs is to allow the Click module to be unloaded and possibly reloaded later, even if the /click file system continues to exist because some userlevel program has a /click/WHATEVER file open. For that reason, most memory having to do with the ifle system MUST be owned by proclikefs, NOT by its user. So statically-allocated file_system_type in the click module is a no go I think: it gives the file system the wrong owner. (Do I misunderstand?) I think a cleaner, better change would simply be to allocate a small static array of struct file_system_types in proclikefs.c. And refuse a proclikefs_register_filesystem request if that array was all allocated. Doe sthis make sense?

[kph]

OK, I fixed the fixincludes.pl and made that the only thing in my pull request. I'll work on a corrected proclikefs patch tomorrow.

Thanks,
Kevin

[kohler]

Excellent. I pulled the fixincludes part.

On 5/11/11 9:09 PM, kph wrote:

OK, I fixed the fixincludes.pl and made that the only thing in my pull request. I'll work on a corrected proclikefs patch tomorrow.

Thanks,
Kevin