2024-05-01 17:02:13

by Breno Leitao

[permalink] [raw]
Subject: [PATCH wireless-next v2] wifi: iwlwifi: pcie: allocate dummy net_device dynamically

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

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 iwl_trans_pcie by converting it
into a pointer. Then use the leverage alloc_netdev() to allocate the
net_device object at iwl_trans_pcie_alloc.

The private data of net_device becomes a pointer for the struct
iwl_trans_pcie, so, it is easy to get back to the iwl_trans_pcie parent
given the net_device object.

[1] https://lore.kernel.org/all/[email protected]/

Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Breno Leitao <[email protected]>
---
Changelog:

v2:
* replaced the alloc_netdev() with the proper dummy allocator
alloc_netdev_dummy().

v1:
* https://lore.kernel.org/all/[email protected]/

---
.../wireless/intel/iwlwifi/pcie/internal.h | 2 +-
drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 11 +++++---
.../net/wireless/intel/iwlwifi/pcie/trans.c | 27 ++++++++++++-------
3 files changed, 27 insertions(+), 13 deletions(-)


PS: This is compiled-tested only due to lack of hardware.

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
index 7805a42948af..a7eebe400b5b 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
@@ -386,7 +386,7 @@ struct iwl_trans_pcie {
dma_addr_t iml_dma_addr;
struct iwl_trans *trans;

- struct net_device napi_dev;
+ struct net_device *napi_dev;

/* INT ICT Table */
__le32 *ict_tbl;
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index 9c2461ba13c5..984d7bcd381f 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -1000,6 +1000,11 @@ void iwl_pcie_rx_init_rxb_lists(struct iwl_rxq *rxq)

static int iwl_pcie_rx_handle(struct iwl_trans *trans, int queue, int budget);

+static inline struct iwl_trans_pcie *iwl_netdev_to_trans_pcie(struct net_device *dev)
+{
+ return *(struct iwl_trans_pcie **)netdev_priv(dev);
+}
+
static int iwl_pcie_napi_poll(struct napi_struct *napi, int budget)
{
struct iwl_rxq *rxq = container_of(napi, struct iwl_rxq, napi);
@@ -1007,7 +1012,7 @@ static int iwl_pcie_napi_poll(struct napi_struct *napi, int budget)
struct iwl_trans *trans;
int ret;

- trans_pcie = container_of(napi->dev, struct iwl_trans_pcie, napi_dev);
+ trans_pcie = iwl_netdev_to_trans_pcie(napi->dev);
trans = trans_pcie->trans;

ret = iwl_pcie_rx_handle(trans, rxq->id, budget);
@@ -1034,7 +1039,7 @@ static int iwl_pcie_napi_poll_msix(struct napi_struct *napi, int budget)
struct iwl_trans *trans;
int ret;

- trans_pcie = container_of(napi->dev, struct iwl_trans_pcie, napi_dev);
+ trans_pcie = iwl_netdev_to_trans_pcie(napi->dev);
trans = trans_pcie->trans;

ret = iwl_pcie_rx_handle(trans, rxq->id, budget);
@@ -1131,7 +1136,7 @@ static int _iwl_pcie_rx_init(struct iwl_trans *trans)
if (trans_pcie->msix_enabled)
poll = iwl_pcie_napi_poll_msix;

- netif_napi_add(&trans_pcie->napi_dev, &rxq->napi,
+ netif_napi_add(trans_pcie->napi_dev, &rxq->napi,
poll);
napi_enable(&rxq->napi);
}
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 6c76b2dd6878..d5a887b3a4bb 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -1986,13 +1986,6 @@ static void iwl_trans_pcie_configure(struct iwl_trans *trans,
trans->command_groups = trans_cfg->command_groups;
trans->command_groups_size = trans_cfg->command_groups_size;

- /* Initialize NAPI here - it should be before registering to mac80211
- * in the opmode but after the HW struct is allocated.
- * As this function may be called again in some corner cases don't
- * do anything if NAPI was already initialized.
- */
- if (trans_pcie->napi_dev.reg_state != NETREG_DUMMY)
- init_dummy_netdev(&trans_pcie->napi_dev);

trans_pcie->fw_reset_handshake = trans_cfg->fw_reset_handshake;
}
@@ -2074,6 +2067,8 @@ void iwl_trans_pcie_free(struct iwl_trans *trans)
iwl_pcie_free_ict(trans);
}

+ free_netdev(trans_pcie->napi_dev);
+
iwl_pcie_free_invalid_tx_cmd(trans);

iwl_pcie_free_fw_monitor(trans);
@@ -3594,7 +3589,7 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
const struct pci_device_id *ent,
const struct iwl_cfg_trans_params *cfg_trans)
{
- struct iwl_trans_pcie *trans_pcie;
+ struct iwl_trans_pcie *trans_pcie, **priv;
struct iwl_trans *trans;
int ret, addr_size;
const struct iwl_trans_ops *ops = &trans_ops_pcie_gen2;
@@ -3623,6 +3618,18 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,

trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);

+ /* Initialize NAPI here - it should be before registering to mac80211
+ * in the opmode but after the HW struct is allocated.
+ */
+ trans_pcie->napi_dev = alloc_netdev_dummy(sizeof(struct iwl_trans_pcie *));
+ if (!trans_pcie->napi_dev) {
+ ret = -ENOMEM;
+ goto out_free_trans;
+ }
+ /* The private struct in netdev is a pointer to struct iwl_trans_pcie */
+ priv = netdev_priv(trans_pcie->napi_dev);
+ *priv = trans_pcie;
+
trans_pcie->trans = trans;
trans_pcie->opmode_down = true;
spin_lock_init(&trans_pcie->irq_lock);
@@ -3637,7 +3644,7 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
WQ_HIGHPRI | WQ_UNBOUND, 0);
if (!trans_pcie->rba.alloc_wq) {
ret = -ENOMEM;
- goto out_free_trans;
+ goto out_free_ndev;
}
INIT_WORK(&trans_pcie->rba.rx_alloc, iwl_pcie_rx_allocator_work);

@@ -3757,6 +3764,8 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
iwl_pcie_free_ict(trans);
out_no_pci:
destroy_workqueue(trans_pcie->rba.alloc_wq);
+out_free_ndev:
+ free_netdev(trans_pcie->napi_dev);
out_free_trans:
iwl_trans_free(trans);
return ERR_PTR(ret);
--
2.43.0