Merge branch 'perf/core' into perf/urgent

Merge reason: Switch from pre-merge topical split to the post-merge urgent track

Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 14 insertions, 3 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 25c3ed594c54..4dc24cc13f5c 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -520,6 +520,14 @@ config LOCK_STAT
 
          For more details, see Documentation/lockstat.txt
 
+         This also enables lock events required by "perf lock",
+         subcommand of perf.
+         If you want to use "perf lock", you also need to turn on
+         CONFIG_EVENT_TRACING.
+
+         CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
+         (CONFIG_LOCKDEP defines "acquire" and "release" events.)
+
 config DEBUG_LOCKDEP
         bool "Lock dependency engine debugging"
         depends on DEBUG_KERNEL && LOCKDEP
diff --git a/lib/idr.c b/lib/idr.c
index ba7d37cf7847..0dc782216d4b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -140,7 +140,8 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
         id = *starting_id;
  restart:
         p = idp->top;
-        l = p->layer;
+        l = idp->layers;
+        pa[l--] = NULL;
         while (1) {
                 /*
                  * We run around this while until we reach the leaf node...
@@ -154,11 +155,13 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
                         oid = id;
                         id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
 
-                        /* did id go over the limit? */
-                        if (id >= (1 << (idp->layers * IDR_BITS))) {
+                        /* if already at the top layer, we need to grow */
+                        if (id >= 1 << (idp->layers * IDR_BITS)) {
                                 *starting_id = id;
                                 return IDR_NEED_TO_GROW;
                         }
+                        p = pa[l];
+                        BUG_ON(!p);
 
                         /* If we need to go up one layer, continue the
                          * loop; otherwise, restart from the top.