Re: [dpdk-dev] [PATCH v2 01/11] bus: add bus iterator to find a particular bus

[Shreyansh Jain]

Hello Gaetan,

On Wednesday 31 May 2017 06:47 PM, Gaetan Rivet wrote:

From: Jan Blunck <jblu...@infradead.org>

Signed-off-by: Jan Blunck <jblu...@infradead.org>
Signed-off-by: Gaetan Rivet <gaetan.ri...@6wind.com>
---
  lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
  lib/librte_eal/common/eal_common_bus.c          | 13 ++++++++++
  lib/librte_eal/common/include/rte_bus.h         | 32 +++++++++++++++++++++++++
  lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
  4 files changed, 47 insertions(+)

diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map 
b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index 2e48a73..ed09ab2 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -162,6 +162,7 @@ DPDK_17.02 {
  DPDK_17.05 {
        global:

+ rte_bus_find;

        rte_cpu_is_supported;
        rte_log_dump;
        rte_log_register;
diff --git a/lib/librte_eal/common/eal_common_bus.c 
b/lib/librte_eal/common/eal_common_bus.c
index 8f9baf8..68f70d0 100644
--- a/lib/librte_eal/common/eal_common_bus.c
+++ b/lib/librte_eal/common/eal_common_bus.c
@@ -145,3 +145,16 @@ rte_bus_dump(FILE *f)
                }
        }
  }
+
+struct rte_bus *
+rte_bus_find(rte_bus_match_t match, const void *data)
+{
+       struct rte_bus *bus = NULL;
+
+       TAILQ_FOREACH(bus, &rte_bus_list, next) {
+               if (match(bus, data))
+                       break;
+       }
+
+       return bus;
+}
diff --git a/lib/librte_eal/common/include/rte_bus.h 
b/lib/librte_eal/common/include/rte_bus.h
index 7c36969..006feca 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -141,6 +141,38 @@ int rte_bus_probe(void);
  void rte_bus_dump(FILE *f);

/**

+ * Bus match function.
+ *
+ * @param bus
+ *     bus under test.
+ *
+ * @param data
+ *     data matched
+ *
+ * @return
+ *     0 if the bus does not match.
+ *     !0 if the bus matches.

One of the common match function implementation could be simply to match
a string. strcmp itself returns '0' for a successful match.
On the same lines, should this function return value be reversed?
-
0 if match
!0 if not a match
-
That way, people would not have to change either the way strcmp works,
for example, or the way various APIs expect '0' as success.

same for rte_device_match_t as well. (in next patch)

+ */
+typedef int (*rte_bus_match_t)(const struct rte_bus *bus, const void *data);
+
+/**
+ * Bus iterator to find a particular bus.
+ *
+ * If the callback returns non-zero this function will stop iterating over
+ * any more buses.
+ *
+ * @param match
+ *      Callback function to check bus
+ *
+ * @param data
+ *      Data to pass to match callback
+ *
+ * @return
+ *      A pointer to a rte_bus structure or NULL in case no bus matches
+ */
+struct rte_bus *rte_bus_find(rte_bus_match_t match, const void *data);
+
+/**
   * Helper for Bus registration.
   * The constructor has higher priority than PMD constructors.
   */
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map 
b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index 670bab3..6efa517 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -166,6 +166,7 @@ DPDK_17.02 {
  DPDK_17.05 {
        global:

+ rte_bus_find;

        rte_cpu_is_supported;
        rte_intr_free_epoll_fd;
        rte_log_dump;