|
|
@@ -0,0 +1,135 @@
|
|
|
+From c661050f93d3fd37a33c06041bb18a89688de7d2 Mon Sep 17 00:00:00 2001
|
|
|
+From: Breno Leitao <[email protected]>
|
|
|
+Date: Mon, 22 Apr 2024 05:38:56 -0700
|
|
|
+Subject: [PATCH] net: create a dummy net_device allocator
|
|
|
+
|
|
|
+It is impossible to use init_dummy_netdev together with alloc_netdev()
|
|
|
+as the 'setup' argument.
|
|
|
+
|
|
|
+This is because alloc_netdev() initializes some fields in the net_device
|
|
|
+structure, and later init_dummy_netdev() memzero them all. This causes
|
|
|
+some problems as reported here:
|
|
|
+
|
|
|
+ https://lore.kernel.org/all/[email protected]/
|
|
|
+
|
|
|
+Split the init_dummy_netdev() function in two. Create a new function called
|
|
|
+init_dummy_netdev_core() that does not memzero the net_device structure.
|
|
|
+Then have init_dummy_netdev() memzero-ing and calling
|
|
|
+init_dummy_netdev_core(), keeping the old behaviour.
|
|
|
+
|
|
|
+init_dummy_netdev_core() is the new function that could be called as an
|
|
|
+argument for alloc_netdev().
|
|
|
+
|
|
|
+Also, create a helper to allocate and initialize dummy net devices,
|
|
|
+leveraging init_dummy_netdev_core() as the setup argument. This function
|
|
|
+basically simplify the allocation of dummy devices, by allocating and
|
|
|
+initializing it. Freeing the device continue to be done through
|
|
|
+free_netdev()
|
|
|
+
|
|
|
+Suggested-by: Jakub Kicinski <[email protected]>
|
|
|
+Signed-off-by: Breno Leitao <[email protected]>
|
|
|
+Reviewed-by: Ido Schimmel <[email protected]>
|
|
|
+Signed-off-by: David S. Miller <[email protected]>
|
|
|
+---
|
|
|
+ include/linux/netdevice.h | 3 +++
|
|
|
+ net/core/dev.c | 56 ++++++++++++++++++++++++++-------------
|
|
|
+ 2 files changed, 41 insertions(+), 18 deletions(-)
|
|
|
+
|
|
|
+--- a/include/linux/netdevice.h
|
|
|
++++ b/include/linux/netdevice.h
|
|
|
+@@ -4549,6 +4549,9 @@ static inline void netif_addr_unlock_bh(
|
|
|
+
|
|
|
+ void ether_setup(struct net_device *dev);
|
|
|
+
|
|
|
++/* Allocate dummy net_device */
|
|
|
++struct net_device *alloc_netdev_dummy(int sizeof_priv);
|
|
|
++
|
|
|
+ /* Support for loadable net-drivers */
|
|
|
+ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
|
|
|
+ unsigned char name_assign_type,
|
|
|
+--- a/net/core/dev.c
|
|
|
++++ b/net/core/dev.c
|
|
|
+@@ -10349,25 +10349,12 @@ err_free_name:
|
|
|
+ }
|
|
|
+ EXPORT_SYMBOL(register_netdevice);
|
|
|
+
|
|
|
+-/**
|
|
|
+- * init_dummy_netdev - init a dummy network device for NAPI
|
|
|
+- * @dev: device to init
|
|
|
+- *
|
|
|
+- * This takes a network device structure and initialize the minimum
|
|
|
+- * amount of fields so it can be used to schedule NAPI polls without
|
|
|
+- * registering a full blown interface. This is to be used by drivers
|
|
|
+- * that need to tie several hardware interfaces to a single NAPI
|
|
|
+- * poll scheduler due to HW limitations.
|
|
|
++/* Initialize the core of a dummy net device.
|
|
|
++ * This is useful if you are calling this function after alloc_netdev(),
|
|
|
++ * since it does not memset the net_device fields.
|
|
|
+ */
|
|
|
+-int init_dummy_netdev(struct net_device *dev)
|
|
|
++static void init_dummy_netdev_core(struct net_device *dev)
|
|
|
+ {
|
|
|
+- /* Clear everything. Note we don't initialize spinlocks
|
|
|
+- * are they aren't supposed to be taken by any of the
|
|
|
+- * NAPI code and this dummy netdev is supposed to be
|
|
|
+- * only ever used for NAPI polls
|
|
|
+- */
|
|
|
+- memset(dev, 0, sizeof(struct net_device));
|
|
|
+-
|
|
|
+ /* make sure we BUG if trying to hit standard
|
|
|
+ * register/unregister code path
|
|
|
+ */
|
|
|
+@@ -10387,12 +10374,32 @@ int init_dummy_netdev(struct net_device
|
|
|
+ * because users of this 'device' dont need to change
|
|
|
+ * its refcount.
|
|
|
+ */
|
|
|
++}
|
|
|
++
|
|
|
++/**
|
|
|
++ * init_dummy_netdev - init a dummy network device for NAPI
|
|
|
++ * @dev: device to init
|
|
|
++ *
|
|
|
++ * This takes a network device structure and initializes the minimum
|
|
|
++ * amount of fields so it can be used to schedule NAPI polls without
|
|
|
++ * registering a full blown interface. This is to be used by drivers
|
|
|
++ * that need to tie several hardware interfaces to a single NAPI
|
|
|
++ * poll scheduler due to HW limitations.
|
|
|
++ */
|
|
|
++int init_dummy_netdev(struct net_device *dev)
|
|
|
++{
|
|
|
++ /* Clear everything. Note we don't initialize spinlocks
|
|
|
++ * as they aren't supposed to be taken by any of the
|
|
|
++ * NAPI code and this dummy netdev is supposed to be
|
|
|
++ * only ever used for NAPI polls
|
|
|
++ */
|
|
|
++ memset(dev, 0, sizeof(struct net_device));
|
|
|
++ init_dummy_netdev_core(dev);
|
|
|
+
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ EXPORT_SYMBOL_GPL(init_dummy_netdev);
|
|
|
+
|
|
|
+-
|
|
|
+ /**
|
|
|
+ * register_netdev - register a network device
|
|
|
+ * @dev: device to register
|
|
|
+@@ -10986,6 +10993,19 @@ void free_netdev(struct net_device *dev)
|
|
|
+ EXPORT_SYMBOL(free_netdev);
|
|
|
+
|
|
|
+ /**
|
|
|
++ * alloc_netdev_dummy - Allocate and initialize a dummy net device.
|
|
|
++ * @sizeof_priv: size of private data to allocate space for
|
|
|
++ *
|
|
|
++ * Return: the allocated net_device on success, NULL otherwise
|
|
|
++ */
|
|
|
++struct net_device *alloc_netdev_dummy(int sizeof_priv)
|
|
|
++{
|
|
|
++ return alloc_netdev(sizeof_priv, "dummy#", NET_NAME_UNKNOWN,
|
|
|
++ init_dummy_netdev_core);
|
|
|
++}
|
|
|
++EXPORT_SYMBOL_GPL(alloc_netdev_dummy);
|
|
|
++
|
|
|
++/**
|
|
|
+ * synchronize_net - Synchronize with packet receive processing
|
|
|
+ *
|
|
|
+ * Wait for packets currently being received to be done.
|
Christian Marangi