[dpdk-dev] [PATCH 1/9] eal: return device handle upon plugin

[Gaetan Rivet <gaetan.rivet@6wind.com>]

This device handle can be useful for other systems calling hotplug
functions, to retrieve for example any associated ethdev.

This change avoids unecessary calls to rte_bus_find, as the handle is
already known and available.

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
---
 lib/librte_eal/common/eal_common_dev.c  | 40 +++++++++++++++++++++++----------
 lib/librte_eal/common/include/rte_dev.h | 10 +++++----
 2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
index 32e12b5..292fefe 100644
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -42,6 +42,7 @@
 #include <rte_devargs.h>
 #include <rte_debug.h>
 #include <rte_devargs.h>
+#include <rte_errno.h>
 #include <rte_log.h>
 
 #include "eal_private.h"
@@ -67,6 +68,7 @@ static int cmp_dev_name(const struct rte_device *dev, const void *_name)
 
 int rte_eal_dev_attach(const char *name, const char *devargs)
 {
+	struct rte_device *dev;
 	int ret;
 
 	if (name == NULL || devargs == NULL) {
@@ -74,9 +76,9 @@ int rte_eal_dev_attach(const char *name, const char *devargs)
 		return -EINVAL;
 	}
 
-	ret = rte_eal_hotplug_add("pci", name, devargs);
-	if (ret && ret != -EINVAL)
-		return ret;
+	dev = rte_eal_hotplug_add("pci", name, devargs);
+	if (dev == NULL && rte_errno != EINVAL)
+		return -rte_errno;
 
 	/*
 	 * If we haven't found a bus device the user meant to "hotplug" a
@@ -118,7 +120,8 @@ int rte_eal_dev_detach(struct rte_device *dev)
 	return ret;
 }
 
-int rte_eal_hotplug_add(const char *busname, const char *devname,
+struct rte_device *
+rte_eal_hotplug_add(const char *busname, const char *devname,
 			const char *devargs)
 {
 	struct rte_bus *bus;
@@ -128,31 +131,39 @@ int rte_eal_hotplug_add(const char *busname, const char *devname,
 	bus = rte_bus_find_by_name(busname);
 	if (bus == NULL) {
 		RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", busname);
-		return -ENOENT;
+		rte_errno = ENOENT;
+		return NULL;
 	}
 
 	if (bus->plug == NULL) {
 		RTE_LOG(ERR, EAL, "Function plug not supported by bus (%s)\n",
 			bus->name);
-		return -ENOTSUP;
+		rte_errno = ENOTSUP;
+		return NULL;
 	}
 
 	ret = bus->scan();
-	if (ret)
-		return ret;
+	if (ret) {
+		rte_errno = -ret;
+		return NULL;
+	}
 
 	dev = bus->find_device(NULL, cmp_detached_dev_name, devname);
 	if (dev == NULL) {
 		RTE_LOG(ERR, EAL, "Cannot find unplugged device (%s)\n",
 			devname);
-		return -EINVAL;
+		rte_errno = EINVAL;
+		return NULL;
 	}
 
 	ret = bus->plug(dev, devargs);
-	if (ret)
+	if (ret) {
 		RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
 			dev->name);
-	return ret;
+		rte_errno = -ret;
+		return NULL;
+	}
+	return dev;
 }
 
 int rte_eal_hotplug_remove(const char *busname, const char *devname)
@@ -164,24 +175,29 @@ int rte_eal_hotplug_remove(const char *busname, const char *devname)
 	bus = rte_bus_find_by_name(busname);
 	if (bus == NULL) {
 		RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", busname);
+		rte_errno = ENOENT;
 		return -ENOENT;
 	}
 
 	if (bus->unplug == NULL) {
 		RTE_LOG(ERR, EAL, "Function unplug not supported by bus (%s)\n",
 			bus->name);
+		rte_errno = ENOTSUP;
 		return -ENOTSUP;
 	}
 
 	dev = bus->find_device(NULL, cmp_dev_name, devname);
 	if (dev == NULL) {
 		RTE_LOG(ERR, EAL, "Cannot find plugged device (%s)\n", devname);
+		rte_errno = EINVAL;
 		return -EINVAL;
 	}
 
 	ret = bus->unplug(dev);
-	if (ret)
+	if (ret) {
 		RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
 			dev->name);
+		rte_errno = -ret;
+	}
 	return ret;
 }
diff --git a/lib/librte_eal/common/include/rte_dev.h b/lib/librte_eal/common/include/rte_dev.h
index bcd8b1e..30d1f2e 100644
--- a/lib/librte_eal/common/include/rte_dev.h
+++ b/lib/librte_eal/common/include/rte_dev.h
@@ -218,10 +218,12 @@ int rte_eal_dev_detach(struct rte_device *dev);
  * @param devargs
  *   Device arguments to be passed to the driver.
  * @return
- *   0 on success, negative on error.
+ *   The pointer to the plugged rte_device on success.
+ *   NULL on error. rte_errno is then set.
  */
-int rte_eal_hotplug_add(const char *busname, const char *devname,
-			const char *devargs);
+struct rte_device *rte_eal_hotplug_add(const char *busname,
+				       const char *devname,
+				       const char *devargs);
 
 /**
  * @warning
@@ -234,7 +236,7 @@ int rte_eal_hotplug_add(const char *busname, const char *devname,
  * @param devname
  *   The device name being removed.
  * @return
- *   0 on success, negative on error.
+ *   0 on success, negative on error. rte_errno is then set.
  */
 int rte_eal_hotplug_remove(const char *busname, const char *devname);
 
-- 
2.1.4