Re: lock_kernel twice possible ?

[Mitchell Blank Jr <mitch@sfgoth.com>]

li nux wrote:
> Sorry, couldn't get what you want to say.
> Can you please elaborate.

A "recursive lock" is one that can be taken multiple times by the same
owner.  So:

	lock_kernel();
	lock_kernel();
	unlock_kernel();
	unlock_kernel();

is perfectly ok.  The lock_kernel() code detects that the calling thread
already owns the lock and just increments current->lock_depth.

Under linux locks are non-recursive EXCEPT for lock_kernel() (aka the BLK
or "big kernel lock")

See lib/kernel_lock.c for more details.

-Mitch
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