[PATCH v2 3/5] net: devres: define a separate devres structure for devm_alloc_etherdev()

Bartosz Golaszewski
2020-05-23T13:27:31Z

Not using a proxy structure to store struct net_device doesn't save
anything in terms of compiled code size or memory usage but significantly
decreases the readability of the code with all the pointer casting.

Define struct net_device_devres and use it in devm_alloc_etherdev_mqs().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
net/devres.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/net/devres.c b/net/devres.c
index c1465d9f9019..b97b0c5a8216 100644
--- a/net/devres.c
+++ b/net/devres.c
@@ -7,30 +7,34 @@
#include <linux/etherdevice.h>
#include <linux/netdevice.h>

-static void devm_free_netdev(struct device *dev, void *res)
+struct net_device_devres {
+ struct net_device *ndev;
+};
+
+static void devm_free_netdev(struct device *dev, void *this)
{
- free_netdev(*(struct net_device **)res);
+ struct net_device_devres *res = this;
+
+ free_netdev(res->ndev);
}

struct net_device *devm_alloc_etherdev_mqs(struct device *dev, int sizeof_priv,
unsigned int txqs, unsigned int rxqs)
{
- struct net_device **dr;
- struct net_device *netdev;
+ struct net_device_devres *dr;

dr = devres_alloc(devm_free_netdev, sizeof(*dr), GFP_KERNEL);
if (!dr)
return NULL;

- netdev = alloc_etherdev_mqs(sizeof_priv, txqs, rxqs);
- if (!netdev) {
+ dr->ndev = alloc_etherdev_mqs(sizeof_priv, txqs, rxqs);
+ if (!dr->ndev) {
devres_free(dr);
return NULL;
}

- *dr = netdev;
devres_add(dev, dr);

- return netdev;
+ return dr->ndev;
}
EXPORT_SYMBOL(devm_alloc_etherdev_mqs);
--
2.25.0