[PATCH net-next v5 00/10] allocate dummy device dynamically

[PATCH net-next v5 00/10] allocate dummy device dynamically

[Breno Leitao]

struct net_device shouldn't be embedded into any structure, instead,
the owner should use the private space to embed their state into
net_device.

But, in some cases the net_device is embedded inside the private
structure, which blocks the usage of zero-length arrays inside
net_device.

Create a helper to allocate a dummy device at dynamically runtime, and
move the Ethernet devices to use it, instead of embedding the dummy
device inside the private structure.

This fixes all the network cases plus some wireless drivers.

PS: Due to lack of hardware, unfortunately most these patches are
compiled tested only, except ath11k that was kindly tested by Kalle Valo.

---
Changelog:

v1:
	* https://lore.kernel.org/all/20240327200809.512867-1-leitao@debian.org/

v2:
	* Patch 1: Use a pre-defined name ("dummy#") for the dummy
	  net_devices.
	* Patch 2-5: Added users for the new helper.
v3:
	* Use free_netdev() instead of kfree() as suggested by Jakub.
	* Change the free_netdev() place in ipa driver, as suggested by
	  Alex Elder.
	* Set err in the error path in the Marvell driver, as suggested
	  by Simon Horman.
v4:
	* Added a new patch to add dummy device at free_netdev(), as suggested
	  by Jakub.
	* Added support for some wireless driver.
	* Added some Acked-by and Reviewed-by.
v5:
	* Added a new patch to fix some typos in the previous code,
	  suggested by Ido.
	* Rebased to net-net/main


Breno Leitao (10):
  net: core: Fix documentation
  net: free_netdev: exit earlier if dummy
  net: create a dummy net_device allocator
  net: marvell: prestera: allocate dummy net_device dynamically
  net: mediatek: mtk_eth_sock: allocate dummy net_device dynamically
  net: ipa: allocate dummy net_device dynamically
  net: ibm/emac: allocate dummy net_device dynamically
  wifi: qtnfmac: Use netdev dummy allocator helper
  wifi: ath10k: allocate dummy net_device dynamically
  wifi: ath11k: allocate dummy net_device dynamically

 drivers/net/ethernet/ibm/emac/mal.c           | 14 ++++-
 drivers/net/ethernet/ibm/emac/mal.h           |  2 +-
 .../ethernet/marvell/prestera/prestera_rxtx.c | 15 ++++-
 drivers/net/ethernet/mediatek/mtk_eth_soc.c   | 17 ++++--
 drivers/net/ethernet/mediatek/mtk_eth_soc.h   |  2 +-
 drivers/net/ipa/gsi.c                         | 12 ++--
 drivers/net/ipa/gsi.h                         |  2 +-
 drivers/net/wireless/ath/ath10k/core.c        |  9 ++-
 drivers/net/wireless/ath/ath10k/core.h        |  2 +-
 drivers/net/wireless/ath/ath10k/pci.c         |  2 +-
 drivers/net/wireless/ath/ath10k/sdio.c        |  2 +-
 drivers/net/wireless/ath/ath10k/snoc.c        |  4 +-
 drivers/net/wireless/ath/ath10k/usb.c         |  2 +-
 drivers/net/wireless/ath/ath11k/ahb.c         |  9 ++-
 drivers/net/wireless/ath/ath11k/core.h        |  2 +-
 drivers/net/wireless/ath/ath11k/pcic.c        | 21 +++++--
 .../wireless/quantenna/qtnfmac/pcie/pcie.c    |  3 +-
 include/linux/netdevice.h                     |  3 +
 net/core/dev.c                                | 57 ++++++++++++-------
 19 files changed, 127 insertions(+), 53 deletions(-)

-- 
2.43.0


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[PATCH net-next v5 01/10] net: core: Fix documentation

[Breno Leitao]

Fix bad grammer in description of init_dummy_netdev() functio.  This
topic showed up in the review of the "allocate dummy device dynamically"
patchset.

Suggested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 net/core/dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 854a3a28a8d8..987039ffa63c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10418,7 +10418,7 @@ 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
+ *	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
@@ -10427,7 +10427,7 @@ EXPORT_SYMBOL(register_netdevice);
 void init_dummy_netdev(struct net_device *dev)
 {
 	/* Clear everything. Note we don't initialize spinlocks
-	 * are they aren't supposed to be taken by any of the
+	 * 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
 	 */
-- 
2.43.0


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Re: [PATCH net-next v5 01/10] net: core: Fix documentation

[Ido Schimmel]

On Wed, Apr 10, 2024 at 06:13:42AM -0700, Breno Leitao wrote:
> Fix bad grammer in description of init_dummy_netdev() functio.  This
> topic showed up in the review of the "allocate dummy device dynamically"
> patchset.
> 
> Suggested-by: Ido Schimmel <idosch@nvidia.com>
> Signed-off-by: Breno Leitao <leitao@debian.org>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

In case you need to send another version:

s/grammer/grammar/
s/functio/function/

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[PATCH net-next v5 02/10] net: free_netdev: exit earlier if dummy

[Breno Leitao]

For dummy devices, exit earlier at free_netdev() instead of executing
the whole function. This is necessary, because dummy devices are
special, and shouldn't have the second part of the function executed.

Otherwise reg_state, which is NETREG_DUMMY, will be overwritten and
there will be no way to identify that this is a dummy device. Also, this
device do not need the final put_device(), since dummy devices are not
registered (through register_netdevice()), where the device reference is
increased (at netdev_register_kobject()/device_add()).

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 net/core/dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 987039ffa63c..c74b42bc6888 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -11060,7 +11060,8 @@ void free_netdev(struct net_device *dev)
 	phy_link_topo_destroy(dev->link_topo);
 
 	/*  Compatibility with error handling in drivers */
-	if (dev->reg_state == NETREG_UNINITIALIZED) {
+	if (dev->reg_state == NETREG_UNINITIALIZED ||
+	    dev->reg_state == NETREG_DUMMY) {
 		netdev_freemem(dev);
 		return;
 	}
-- 
2.43.0


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Re: [PATCH net-next v5 02/10] net: free_netdev: exit earlier if dummy

[Ido Schimmel]

On Wed, Apr 10, 2024 at 06:13:43AM -0700, Breno Leitao wrote:
> For dummy devices, exit earlier at free_netdev() instead of executing
> the whole function. This is necessary, because dummy devices are
> special, and shouldn't have the second part of the function executed.
> 
> Otherwise reg_state, which is NETREG_DUMMY, will be overwritten and
> there will be no way to identify that this is a dummy device. Also, this
> device do not need the final put_device(), since dummy devices are not
> registered (through register_netdevice()), where the device reference is
> increased (at netdev_register_kobject()/device_add()).
> 
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Breno Leitao <leitao@debian.org>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

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[PATCH net-next v5 03/10] net: create a dummy net_device allocator

[Breno Leitao]

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/20240322082336.49f110cc@kernel.org/

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 <kuba@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---
 include/linux/netdevice.h |  3 +++
 net/core/dev.c            | 54 ++++++++++++++++++++++++++-------------
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d45f330d083d..f849e7d110ed 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4519,6 +4519,9 @@ static inline void netif_addr_unlock_bh(struct net_device *dev)
 
 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,
diff --git a/net/core/dev.c b/net/core/dev.c
index c74b42bc6888..417abfd12871 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10414,25 +10414,12 @@ int register_netdevice(struct net_device *dev)
 }
 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 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.
+/* 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.
  */
-void 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
-	 * 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));
-
 	/* make sure we BUG if trying to hit standard
 	 * register/unregister code path
 	 */
@@ -10453,8 +10440,28 @@ void init_dummy_netdev(struct net_device *dev)
 	 * its refcount.
 	 */
 }
-EXPORT_SYMBOL_GPL(init_dummy_netdev);
 
+/**
+ *	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.
+ */
+void 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);
+}
+EXPORT_SYMBOL_GPL(init_dummy_netdev);
 
 /**
  *	register_netdev	- register a network device
@@ -11074,6 +11081,17 @@ 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
+ */
+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
  *
-- 
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[PATCH net-next v5 04/10] net: marvell: prestera: allocate dummy net_device dynamically

[Breno Leitao]

Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_device from the private struct by converting it
into a pointer. Then use the leverage the new alloc_netdev_dummy()
helper to allocate and initialize dummy devices.

[1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/

Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Elad Nachman <enachman@marvell.com>
---
 .../net/ethernet/marvell/prestera/prestera_rxtx.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c b/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c
index cc2a9ae794be..39d9bf82c115 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c
@@ -96,7 +96,7 @@ struct prestera_sdma {
 	struct dma_pool *desc_pool;
 	struct work_struct tx_work;
 	struct napi_struct rx_napi;
-	struct net_device napi_dev;
+	struct net_device *napi_dev;
 	u32 map_addr;
 	u64 dma_mask;
 	/* protect SDMA with concurrent access from multiple CPUs */
@@ -654,13 +654,21 @@ static int prestera_sdma_switch_init(struct prestera_switch *sw)
 	if (err)
 		goto err_evt_register;
 
-	init_dummy_netdev(&sdma->napi_dev);
+	sdma->napi_dev = alloc_netdev_dummy(0);
+	if (!sdma->napi_dev) {
+		dev_err(dev, "not able to initialize dummy device\n");
+		err = -ENOMEM;
+		goto err_alloc_dummy;
+	}
 
-	netif_napi_add(&sdma->napi_dev, &sdma->rx_napi, prestera_sdma_rx_poll);
+	netif_napi_add(sdma->napi_dev, &sdma->rx_napi, prestera_sdma_rx_poll);
 	napi_enable(&sdma->rx_napi);
 
 	return 0;
 
+err_alloc_dummy:
+	prestera_hw_event_handler_unregister(sw, PRESTERA_EVENT_TYPE_RXTX,
+					     prestera_rxtx_handle_event);
 err_evt_register:
 err_tx_init:
 	prestera_sdma_tx_fini(sdma);
@@ -677,6 +685,7 @@ static void prestera_sdma_switch_fini(struct prestera_switch *sw)
 
 	napi_disable(&sdma->rx_napi);
 	netif_napi_del(&sdma->rx_napi);
+	free_netdev(sdma->napi_dev);
 	prestera_hw_event_handler_unregister(sw, PRESTERA_EVENT_TYPE_RXTX,
 					     prestera_rxtx_handle_event);
 	prestera_sdma_tx_fini(sdma);
-- 
2.43.0


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[PATCH net-next v5 05/10] net: mediatek: mtk_eth_sock: allocate dummy net_device dynamically

[Breno Leitao]

Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_device from the private struct by converting it
into a pointer. Then use the leverage the new alloc_netdev_dummy()
helper to allocate and initialize dummy devices.

[1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 17 +++++++++++++----
 drivers/net/ethernet/mediatek/mtk_eth_soc.h |  2 +-
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index caa13b9cedff..d7a96dc11c07 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1710,7 +1710,7 @@ static struct page_pool *mtk_create_page_pool(struct mtk_eth *eth,
 	if (IS_ERR(pp))
 		return pp;
 
-	err = __xdp_rxq_info_reg(xdp_q, &eth->dummy_dev, id,
+	err = __xdp_rxq_info_reg(xdp_q, eth->dummy_dev, id,
 				 eth->rx_napi.napi_id, PAGE_SIZE);
 	if (err < 0)
 		goto err_free_pp;
@@ -4188,6 +4188,8 @@ static int mtk_free_dev(struct mtk_eth *eth)
 		metadata_dst_free(eth->dsa_meta[i]);
 	}
 
+	free_netdev(eth->dummy_dev);
+
 	return 0;
 }
 
@@ -4983,9 +4985,14 @@ static int mtk_probe(struct platform_device *pdev)
 	/* we run 2 devices on the same DMA ring so we need a dummy device
 	 * for NAPI to work
 	 */
-	init_dummy_netdev(&eth->dummy_dev);
-	netif_napi_add(&eth->dummy_dev, &eth->tx_napi, mtk_napi_tx);
-	netif_napi_add(&eth->dummy_dev, &eth->rx_napi, mtk_napi_rx);
+	eth->dummy_dev = alloc_netdev_dummy(0);
+	if (!eth->dummy_dev) {
+		err = -ENOMEM;
+		dev_err(eth->dev, "failed to allocated dummy device\n");
+		goto err_unreg_netdev;
+	}
+	netif_napi_add(eth->dummy_dev, &eth->tx_napi, mtk_napi_tx);
+	netif_napi_add(eth->dummy_dev, &eth->rx_napi, mtk_napi_rx);
 
 	platform_set_drvdata(pdev, eth);
 	schedule_delayed_work(&eth->reset.monitor_work,
@@ -4993,6 +5000,8 @@ static int mtk_probe(struct platform_device *pdev)
 
 	return 0;
 
+err_unreg_netdev:
+	mtk_unreg_dev(eth);
 err_deinit_ppe:
 	mtk_ppe_deinit(eth);
 	mtk_mdio_cleanup(eth);
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 9ae3b8a71d0e..723fc637027c 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -1242,7 +1242,7 @@ struct mtk_eth {
 	spinlock_t			page_lock;
 	spinlock_t			tx_irq_lock;
 	spinlock_t			rx_irq_lock;
-	struct net_device		dummy_dev;
+	struct net_device		*dummy_dev;
 	struct net_device		*netdev[MTK_MAX_DEVS];
 	struct mtk_mac			*mac[MTK_MAX_DEVS];
 	int				irq[3];
-- 
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[PATCH net-next v5 06/10] net: ipa: allocate dummy net_device dynamically

[Breno Leitao]

Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_device from the private struct by converting it
into a pointer. Then use the leverage the new alloc_netdev_dummy()
helper to allocate and initialize dummy devices.

[1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/ipa/gsi.c | 12 ++++++++----
 drivers/net/ipa/gsi.h |  2 +-
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 9a0b1fe4a93a..d70be15e95a6 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -1730,10 +1730,10 @@ static int gsi_channel_setup_one(struct gsi *gsi, u32 channel_id)
 	gsi_channel_program(channel, true);
 
 	if (channel->toward_ipa)
-		netif_napi_add_tx(&gsi->dummy_dev, &channel->napi,
+		netif_napi_add_tx(gsi->dummy_dev, &channel->napi,
 				  gsi_channel_poll);
 	else
-		netif_napi_add(&gsi->dummy_dev, &channel->napi,
+		netif_napi_add(gsi->dummy_dev, &channel->napi,
 			       gsi_channel_poll);
 
 	return 0;
@@ -2369,12 +2369,14 @@ int gsi_init(struct gsi *gsi, struct platform_device *pdev,
 	/* GSI uses NAPI on all channels.  Create a dummy network device
 	 * for the channel NAPI contexts to be associated with.
 	 */
-	init_dummy_netdev(&gsi->dummy_dev);
+	gsi->dummy_dev = alloc_netdev_dummy(0);
+	if (!gsi->dummy_dev)
+		return -ENOMEM;
 	init_completion(&gsi->completion);
 
 	ret = gsi_reg_init(gsi, pdev);
 	if (ret)
-		return ret;
+		goto err_reg_exit;
 
 	ret = gsi_irq_init(gsi, pdev);	/* No matching exit required */
 	if (ret)
@@ -2389,6 +2391,7 @@ int gsi_init(struct gsi *gsi, struct platform_device *pdev,
 	return 0;
 
 err_reg_exit:
+	free_netdev(gsi->dummy_dev);
 	gsi_reg_exit(gsi);
 
 	return ret;
@@ -2399,6 +2402,7 @@ void gsi_exit(struct gsi *gsi)
 {
 	mutex_destroy(&gsi->mutex);
 	gsi_channel_exit(gsi);
+	free_netdev(gsi->dummy_dev);
 	gsi_reg_exit(gsi);
 }
 
diff --git a/drivers/net/ipa/gsi.h b/drivers/net/ipa/gsi.h
index 42063b227c18..6b7ec2a39676 100644
--- a/drivers/net/ipa/gsi.h
+++ b/drivers/net/ipa/gsi.h
@@ -155,7 +155,7 @@ struct gsi {
 	struct mutex mutex;		/* protects commands, programming */
 	struct gsi_channel channel[GSI_CHANNEL_COUNT_MAX];
 	struct gsi_evt_ring evt_ring[GSI_EVT_RING_COUNT_MAX];
-	struct net_device dummy_dev;	/* needed for NAPI */
+	struct net_device *dummy_dev;	/* needed for NAPI */
 };
 
 /**
-- 
2.43.0


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[PATCH net-next v5 07/10] net: ibm/emac: allocate dummy net_device dynamically

[Breno Leitao]

Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_device from the private struct by converting it
into a pointer. Then use the leverage the new alloc_netdev_dummy()
helper to allocate and initialize dummy devices.

[1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/ethernet/ibm/emac/mal.c | 14 +++++++++++---
 drivers/net/ethernet/ibm/emac/mal.h |  2 +-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/ibm/emac/mal.c b/drivers/net/ethernet/ibm/emac/mal.c
index 2439f7e96e05..d92dd9c83031 100644
--- a/drivers/net/ethernet/ibm/emac/mal.c
+++ b/drivers/net/ethernet/ibm/emac/mal.c
@@ -605,9 +605,13 @@ static int mal_probe(struct platform_device *ofdev)
 	INIT_LIST_HEAD(&mal->list);
 	spin_lock_init(&mal->lock);
 
-	init_dummy_netdev(&mal->dummy_dev);
+	mal->dummy_dev = alloc_netdev_dummy(0);
+	if (!mal->dummy_dev) {
+		err = -ENOMEM;
+		goto fail_unmap;
+	}
 
-	netif_napi_add_weight(&mal->dummy_dev, &mal->napi, mal_poll,
+	netif_napi_add_weight(mal->dummy_dev, &mal->napi, mal_poll,
 			      CONFIG_IBM_EMAC_POLL_WEIGHT);
 
 	/* Load power-on reset defaults */
@@ -637,7 +641,7 @@ static int mal_probe(struct platform_device *ofdev)
 					  GFP_KERNEL);
 	if (mal->bd_virt == NULL) {
 		err = -ENOMEM;
-		goto fail_unmap;
+		goto fail_dummy;
 	}
 
 	for (i = 0; i < mal->num_tx_chans; ++i)
@@ -703,6 +707,8 @@ static int mal_probe(struct platform_device *ofdev)
 	free_irq(mal->serr_irq, mal);
  fail2:
 	dma_free_coherent(&ofdev->dev, bd_size, mal->bd_virt, mal->bd_dma);
+ fail_dummy:
+	free_netdev(mal->dummy_dev);
  fail_unmap:
 	dcr_unmap(mal->dcr_host, 0x100);
  fail:
@@ -734,6 +740,8 @@ static void mal_remove(struct platform_device *ofdev)
 
 	mal_reset(mal);
 
+	free_netdev(mal->dummy_dev);
+
 	dma_free_coherent(&ofdev->dev,
 			  sizeof(struct mal_descriptor) *
 			  (NUM_TX_BUFF * mal->num_tx_chans +
diff --git a/drivers/net/ethernet/ibm/emac/mal.h b/drivers/net/ethernet/ibm/emac/mal.h
index d212373a72e7..e0ddc41186a2 100644
--- a/drivers/net/ethernet/ibm/emac/mal.h
+++ b/drivers/net/ethernet/ibm/emac/mal.h
@@ -205,7 +205,7 @@ struct mal_instance {
 	int			index;
 	spinlock_t		lock;
 
-	struct net_device	dummy_dev;
+	struct net_device	*dummy_dev;
 
 	unsigned int features;
 };
-- 
2.43.0


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[PATCH net-next v5 08/10] wifi: qtnfmac: Use netdev dummy allocator helper

[Breno Leitao]

There is a new dummy netdev allocator, use it instead of
alloc_netdev()/init_dummy_netdev combination.

Using alloc_netdev() with init_dummy_netdev might cause some memory
corruption at the driver removal side.

Fixes: 61cdb09ff760 ("wifi: qtnfmac: allocate dummy net_device dynamically")
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/wireless/quantenna/qtnfmac/pcie/pcie.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/wireless/quantenna/qtnfmac/pcie/pcie.c b/drivers/net/wireless/quantenna/qtnfmac/pcie/pcie.c
index f8f55db2f454..f66eb43094d4 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/pcie/pcie.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/pcie/pcie.c
@@ -372,8 +372,7 @@ static int qtnf_pcie_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto error;
 	}
 
-	bus->mux_dev = alloc_netdev(0, "dummy", NET_NAME_UNKNOWN,
-				    init_dummy_netdev);
+	bus->mux_dev = alloc_netdev_dummy(0);
 	if (!bus->mux_dev) {
 		ret = -ENOMEM;
 		goto error;
-- 
2.43.0


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[PATCH net-next v5 09/10] wifi: ath10k: allocate dummy net_device dynamically

[Breno Leitao]

Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_device from struct ath10k by converting it
into a pointer. Then use the leverage alloc_netdev() to allocate the
net_device object at ath10k_core_create(). The free of the device occurs
at ath10k_core_destroy().

[1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/wireless/ath/ath10k/core.c | 9 +++++++--
 drivers/net/wireless/ath/ath10k/core.h | 2 +-
 drivers/net/wireless/ath/ath10k/pci.c  | 2 +-
 drivers/net/wireless/ath/ath10k/sdio.c | 2 +-
 drivers/net/wireless/ath/ath10k/snoc.c | 4 ++--
 drivers/net/wireless/ath/ath10k/usb.c  | 2 +-
 6 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 9ce6f49ab261..8663822e0b8d 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -3673,11 +3673,13 @@ struct ath10k *ath10k_core_create(size_t priv_size, struct device *dev,
 	INIT_WORK(&ar->set_coverage_class_work,
 		  ath10k_core_set_coverage_class_work);
 
-	init_dummy_netdev(&ar->napi_dev);
+	ar->napi_dev = alloc_netdev_dummy(0);
+	if (!ar->napi_dev)
+		goto err_free_tx_complete;
 
 	ret = ath10k_coredump_create(ar);
 	if (ret)
-		goto err_free_tx_complete;
+		goto err_free_netdev;
 
 	ret = ath10k_debug_create(ar);
 	if (ret)
@@ -3687,6 +3689,8 @@ struct ath10k *ath10k_core_create(size_t priv_size, struct device *dev,
 
 err_free_coredump:
 	ath10k_coredump_destroy(ar);
+err_free_netdev:
+	free_netdev(ar->napi_dev);
 err_free_tx_complete:
 	destroy_workqueue(ar->workqueue_tx_complete);
 err_free_aux_wq:
@@ -3708,6 +3712,7 @@ void ath10k_core_destroy(struct ath10k *ar)
 
 	destroy_workqueue(ar->workqueue_tx_complete);
 
+	free_netdev(ar->napi_dev);
 	ath10k_debug_destroy(ar);
 	ath10k_coredump_destroy(ar);
 	ath10k_htt_tx_destroy(&ar->htt);
diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index c110d15528bd..26003b519574 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -1269,7 +1269,7 @@ struct ath10k {
 	struct ath10k_per_peer_tx_stats peer_tx_stats;
 
 	/* NAPI */
-	struct net_device napi_dev;
+	struct net_device *napi_dev;
 	struct napi_struct napi;
 
 	struct work_struct set_coverage_class_work;
diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 5c34b156b4ff..558bec96ae40 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -3217,7 +3217,7 @@ static void ath10k_pci_free_irq(struct ath10k *ar)
 
 void ath10k_pci_init_napi(struct ath10k *ar)
 {
-	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_pci_napi_poll);
+	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_pci_napi_poll);
 }
 
 static int ath10k_pci_init_irq(struct ath10k *ar)
diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
index 0ab5433f6cf6..e28f2fe1101b 100644
--- a/drivers/net/wireless/ath/ath10k/sdio.c
+++ b/drivers/net/wireless/ath/ath10k/sdio.c
@@ -2532,7 +2532,7 @@ static int ath10k_sdio_probe(struct sdio_func *func,
 		return -ENOMEM;
 	}
 
-	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_sdio_napi_poll);
+	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_sdio_napi_poll);
 
 	ath10k_dbg(ar, ATH10K_DBG_BOOT,
 		   "sdio new func %d vendor 0x%x device 0x%x block 0x%x/0x%x\n",
diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
index 2c39bad7ebfb..0449b9ffc32d 100644
--- a/drivers/net/wireless/ath/ath10k/snoc.c
+++ b/drivers/net/wireless/ath/ath10k/snoc.c
@@ -935,7 +935,7 @@ static int ath10k_snoc_hif_start(struct ath10k *ar)
 
 	bitmap_clear(ar_snoc->pending_ce_irqs, 0, CE_COUNT_MAX);
 
-	dev_set_threaded(&ar->napi_dev, true);
+	dev_set_threaded(ar->napi_dev, true);
 	ath10k_core_napi_enable(ar);
 	ath10k_snoc_irq_enable(ar);
 	ath10k_snoc_rx_post(ar);
@@ -1253,7 +1253,7 @@ static int ath10k_snoc_napi_poll(struct napi_struct *ctx, int budget)
 
 static void ath10k_snoc_init_napi(struct ath10k *ar)
 {
-	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_snoc_napi_poll);
+	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_snoc_napi_poll);
 }
 
 static int ath10k_snoc_request_irq(struct ath10k *ar)
diff --git a/drivers/net/wireless/ath/ath10k/usb.c b/drivers/net/wireless/ath/ath10k/usb.c
index 3c482baacec1..3b51b7f52130 100644
--- a/drivers/net/wireless/ath/ath10k/usb.c
+++ b/drivers/net/wireless/ath/ath10k/usb.c
@@ -1014,7 +1014,7 @@ static int ath10k_usb_probe(struct usb_interface *interface,
 		return -ENOMEM;
 	}
 
-	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_usb_napi_poll);
+	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_usb_napi_poll);
 
 	usb_get_dev(dev);
 	vendor_id = le16_to_cpu(dev->descriptor.idVendor);
-- 
2.43.0


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Re: [PATCH net-next v5 00/10] allocate dummy device dynamically

[Kalle Valo]

Breno Leitao <leitao@debian.org> writes:

> struct net_device shouldn't be embedded into any structure, instead,
> the owner should use the private space to embed their state into
> net_device.
>
> But, in some cases the net_device is embedded inside the private
> structure, which blocks the usage of zero-length arrays inside
> net_device.
>
> Create a helper to allocate a dummy device at dynamically runtime, and
> move the Ethernet devices to use it, instead of embedding the dummy
> device inside the private structure.
>
> This fixes all the network cases plus some wireless drivers.
>
> PS: Due to lack of hardware, unfortunately most these patches are
> compiled tested only, except ath11k that was kindly tested by Kalle Valo.
>
> ---
> Changelog:
>
> v1:
> 	* https://lore.kernel.org/all/20240327200809.512867-1-leitao@debian.org/
>
> v2:
> 	* Patch 1: Use a pre-defined name ("dummy#") for the dummy
> 	  net_devices.
> 	* Patch 2-5: Added users for the new helper.
> v3:
> 	* Use free_netdev() instead of kfree() as suggested by Jakub.
> 	* Change the free_netdev() place in ipa driver, as suggested by
> 	  Alex Elder.
> 	* Set err in the error path in the Marvell driver, as suggested
> 	  by Simon Horman.
> v4:
> 	* Added a new patch to add dummy device at free_netdev(), as suggested
> 	  by Jakub.
> 	* Added support for some wireless driver.
> 	* Added some Acked-by and Reviewed-by.
> v5:
> 	* Added a new patch to fix some typos in the previous code,
> 	  suggested by Ido.
> 	* Rebased to net-net/main

I'm nitpicking here but I prefer to have the changelog in reverse order,
that is v5 first and v1 last. I'm most interested about the changes in
v5, I don't care about v1 at this point. Though I don't know if net
folks have a different prefence, just wanted to mention this.

-- 
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https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

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Re: [PATCH net-next v5 00/10] allocate dummy device dynamically

[Jakub Kicinski]

On Wed, 10 Apr 2024 06:13:41 -0700 Breno Leitao wrote:
>   wifi: ath11k: allocate dummy net_device dynamically

Sorry Breno, I didn't notice earlier, patch 10 didn't make it
to the list. The series wasn't ingested by CI and tested because 
of this. Could you repost?
-- 
pw-bot: cr

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Re: [PATCH net-next v5 00/10] allocate dummy device dynamically

[Breno Leitao]

On Thu, Apr 11, 2024 at 06:09:26AM -0700, Jakub Kicinski wrote:
> On Wed, 10 Apr 2024 06:13:41 -0700 Breno Leitao wrote:
> >   wifi: ath11k: allocate dummy net_device dynamically
> 
> Sorry Breno, I didn't notice earlier, patch 10 didn't make it
> to the list. The series wasn't ingested by CI and tested because 
> of this. Could you repost?

Thanks for the heads-up. I debugged it and it was my mistake, this is
how I've sent it.

	git send-email patches/v5-000*

I will repost.

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