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Commit 38aa2714 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

lockdep: add comments to mark_lock_irq() 



re-add some of the comments that got lost in the refactoring.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent cf2ad4d1

kernel/lockdep.c

+30 −7
Original line number Diff line number Diff line
@@ -2054,6 +2054,9 @@ static int exclusive_bit(int new_bit) 
	int state = new_bit & ~3;

	int dir = new_bit & 2;



	/*

	 * keep state, bit flip the direction and strip read.

	 */

	return state | (dir ^ 2);

}
@@ -2070,22 +2073,42 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit) 
	int read = new_bit & 1;

	int dir = new_bit & 2;



	/*

	 * mark USED_IN has to look forwards -- to ensure no dependency

	 * has ENABLED state, which would allow recursion deadlocks.

	 *

	 * mark ENABLED has to look backwards -- to ensure no dependee

	 * has USED_IN state, which, again, would allow  recursion deadlocks.

	 */

	check_usage_f usage = dir ?

		check_usage_backwards : check_usage_forwards;



	/*

	 * Validate that this particular lock does not have conflicting

	 * usage states.

	 */

	if (!valid_state(curr, this, new_bit, excl_bit))

		return 0;



	if (!read && !valid_state(curr, this, new_bit, excl_bit + 1))

	/*

	 * Validate that the lock dependencies don't have conflicting usage

	 * states.

	 */

	if ((!read || !dir || STRICT_READ_CHECKS) &&

			!usage(curr, this, excl_bit, name))

		return 0;



	if ((!read || (!dir || STRICT_READ_CHECKS)) &&

			!usage(curr, this, excl_bit, name))

	/*

	 * Check for read in write conflicts

	 */

	if (!read) {

		if (!valid_state(curr, this, new_bit, excl_bit + 1))

			return 0;



	if ((!read && STRICT_READ_CHECKS) &&

		if (STRICT_READ_CHECKS &&

				!usage(curr, this, excl_bit + 1, rname))

			return 0;

	}



	if (state_verbose(new_bit, hlock_class(this)))

		return 2;