lockdep: Add recursive read locks into dependency graph

Since we have all the fundamental to handle recursive read locks, we now add them into the dependency graph.

Boqun Feng committed 6 years ago

Commit 621c9da1 parent f08e3881 file · +2 −17Browse files

Showing the changes to kernel (1 of 1 file). Show all

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@@ -2808,16 +2808,6 @@ check_prev_add(struct task_struct curr, struct held_lock prev, · 2807 unmodified lines
2808	2808	if (!check_irq_usage(curr, prev, next))
2809	2809	return 0;
2810	2810
2811		− /*
2812		− * For recursive read-locks we do all the dependency checks,
2813		− * but we dont store read-triggered dependencies (only
2814		− * write-triggered dependencies). This ensures that only the
2815		− * write-side dependencies matter, and that if for example a
2816		− * write-lock never takes any other locks, then the reads are
2817		− * equivalent to a NOP.
2818		− */
2819		− if (next->read == 2 \|\| prev->read == 2)
2820		− return 1;
2821	2811	/*
2822	2812	* Is the <prev> -> <next> dependency already present?
2823	2813	*
@@ -2935,13 +2925,8 @@ check_prevs_add(struct task_struct curr, struct held_lock next) · 111 unmodified lines
2935	2925	u16 distance = curr->lockdep_depth - depth + 1;
2936	2926	hlock = curr->held_locks + depth - 1;
2937	2927
2938		− /*
2939		− * Only non-recursive-read entries get new dependencies
2940		− * added:
2941		− */
2942		− if (hlock->read != 2 && hlock->check) {
2943		− int ret = check_prev_add(curr, hlock, next, distance,
2944		− &trace);
	2928	+ if (hlock->check) {
	2929	+ int ret = check_prev_add(curr, hlock, next, distance, &trace);
2945	2930	if (!ret)
2946	2931	return 0;
2947	2932

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