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@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200206152408.24165-3-longman@redhat.com

diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 231684cfc5aecb1877d775b9725b1cf3d961d45a..c2224381c149d75483784e832162a155e3e535f9 100644 (file)
--- 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);