[dpdk-dev] [PATCH v6] eal:add tailq walk routine

[Keith Wiles <keith.wiles@intel.com>]

Add the tailq walk routine for debugging and other uses.
This routine will hold the read lock while walking the list.

Signed-off-by: Keith Wiles <keith.wiles@intel.com>
---
V6
  Remove warning
V5
  Fixup checkpatch warnings.
V4
  Change function to have a return value.
  to be used to stop walking or continue walking.
V3
  Fix checkpatch warnings adding a commit message.
  Must be using a different checkpatch then on my Ubuntu 18.04 system 
V2
  Fix checkpatch warnings.

 lib/librte_eal/common/eal_common_tailqs.c | 20 ++++++++++++++++++++
 lib/librte_eal/common/include/rte_tailq.h | 16 ++++++++++++++++
 lib/librte_eal/rte_eal_version.map        |  1 +
 3 files changed, 37 insertions(+)

diff --git a/lib/librte_eal/common/eal_common_tailqs.c b/lib/librte_eal/common/eal_common_tailqs.c
index babd3b30a..99e898019 100644
--- a/lib/librte_eal/common/eal_common_tailqs.c
+++ b/lib/librte_eal/common/eal_common_tailqs.c
@@ -69,6 +69,26 @@ rte_dump_tailq(FILE *f)
 	rte_rwlock_read_unlock(&mcfg->qlock);
 }
 
+void
+rte_tailq_walk(int (*iter)(const struct rte_tailq_head *, void *), void *arg)
+{
+	struct rte_mem_config *mcfg;
+	unsigned int i = 0;
+
+	if (!iter)
+		return;
+	mcfg = rte_eal_get_configuration()->mem_config;
+
+	rte_rwlock_read_lock(&mcfg->qlock);
+	for (i = 0; i < RTE_MAX_TAILQ; i++) {
+		const struct rte_tailq_head *tailq = &mcfg->tailq_head[i];
+
+		if (iter(tailq, arg) < 0)
+			break;
+	}
+	rte_rwlock_read_unlock(&mcfg->qlock);
+}
+
 static struct rte_tailq_head *
 rte_eal_tailq_create(const char *name)
 {
diff --git a/lib/librte_eal/common/include/rte_tailq.h b/lib/librte_eal/common/include/rte_tailq.h
index 9b01abb2c..25e99658b 100644
--- a/lib/librte_eal/common/include/rte_tailq.h
+++ b/lib/librte_eal/common/include/rte_tailq.h
@@ -18,6 +18,7 @@ extern "C" {
 #include <sys/queue.h>
 #include <stdio.h>
 #include <rte_debug.h>
+#include <rte_compat.h>
 
 /** dummy structure type used by the rte_tailq APIs */
 struct rte_tailq_entry {
@@ -85,6 +86,21 @@ struct rte_tailq_elem {
  */
 void rte_dump_tailq(FILE *f);
 
+/**
+ * Walk the tailq list and call the Iterator function given.
+ *
+ * @param func
+ *   Iterator function called for each tailq list.
+ *   The rte_eal_get_configuration()->mem_config.qlock read lock is held.
+ *   If Iterator returns < 0 then break out of loop.
+ *   If Iterator returns 0 then continue looping.
+ * @param arg
+ *   pointer to user supplied argument passed to Iterator function.
+ */
+void __rte_experimental
+	rte_tailq_walk(int (*iter)(const struct rte_tailq_head *, void *),
+	void *arg);
+
 /**
  * Lookup for a tail queue.
  *
diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
index eb5f7b9cb..288b20b0e 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -364,4 +364,5 @@ EXPERIMENTAL {
 	rte_service_may_be_active;
 	rte_socket_count;
 	rte_socket_id_by_idx;
+	rte_tailq_walk;
 };
-- 
2.17.1