[tip: locking/core] locking/lockdep: Display irq_context names in /proc/lockdep_chains

[tip-bot2 for Waiman Long]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     b9875e9882295749a14b31e16dd504ae904cf070
Gitweb:        https://git.kernel.org/tip/b9875e9882295749a14b31e16dd504ae904cf070
Author:        Waiman Long <longman@xxxxxxxxxx>
AuthorDate:    Thu, 06 Feb 2020 10:24:04 -05:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 11 Feb 2020 13:10:48 +01:00

locking/lockdep: Display irq_context names in /proc/lockdep_chains

Currently, the irq_context field of a lock chains displayed in
/proc/lockdep_chains is just a number. It is likely that many people
may not know what a non-zero number means. To make the information more
useful, print the actual irq names ("softirq" and "hardirq") instead.

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200206152408.24165-3-longman@xxxxxxxxxx
---
 kernel/locking/lockdep_proc.c |  9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 231684c..c222438 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -128,6 +128,13 @@ static int lc_show(struct seq_file *m, void *v)
 	struct lock_chain *chain = v;
 	struct lock_class *class;
 	int i;
+	static const char * const irq_strs[] = {
+		[0]			     = "0",
+		[LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq",
+		[LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq",
+		[LOCK_CHAIN_SOFTIRQ_CONTEXT|
+		 LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq",
+	};
 
 	if (v == SEQ_START_TOKEN) {
 		if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
@@ -136,7 +143,7 @@ static int lc_show(struct seq_file *m, void *v)
 		return 0;
 	}
 
-	seq_printf(m, "irq_context: %d\n", chain->irq_context);
+	seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]);
 
 	for (i = 0; i < chain->depth; i++) {
 		class = lock_chain_get_class(chain, i);