From: Gautham R Shenoy Do various simplifications: 1) In kernel/lockdep.c::validate_chain(): ret = check_deadlock(curr, hlock, lock, hlock->read); ret == 2 only if hlock->read == 2. Hence: if (ret == 2) hlock->read = 2; is redundant and can be removed. 2) In kernel/lockdep.c::check_prevs_add(curr, next): if (hlock->read != 2) check_prev_add(curr, hlock, next, distance); Thus, check_prev_add is called only when hlock->read != 2. >From the conclusions of 2): kernel/lockdep.c::check_prev_add(curr, prev, next, distance) gets called iff prev->read != 2. Hence, in kernel/lockdep.c::check_prev_add(curr, prev, next, distance): if (prev->read == 2) return 1; is redunant and can be removed. Signed-off-by: Gautham R Shenoy Signed-off-by: Peter Zijlstra --- kernel/lockdep.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) Index: tip/kernel/lockdep.c =================================================================== --- tip.orig/kernel/lockdep.c +++ tip/kernel/lockdep.c @@ -1676,7 +1676,7 @@ check_prev_add(struct task_struct *curr, * write-lock never takes any other locks, then the reads are * equivalent to a NOP. */ - if (next->read == 2 || prev->read == 2) + if (next->read == 2) return 1; /* * Is the -> dependency already present? @@ -1940,13 +1940,6 @@ static int validate_chain(struct task_st if (!ret) return 0; /* - * Mark recursive read, as we jump over it when - * building dependencies (just like we jump over - * trylock entries): - */ - if (ret == 2) - hlock->read = 2; - /* * Add dependency only if this lock is not the head * of the chain, and if it's not a secondary read-lock: */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/