wifi: wilc1000: use SRCU instead of RCU for vif list traversal

Enabling CONFIG_PROVE_RCU_LIST raises many warnings in wilc driver, even on
some places already protected by a read critical section. An example of
such case is in wilc_get_available_idx:

=============================
WARNING: suspicious RCU usage
6.8.0-rc1+ #32 Not tainted
-----------------------------
drivers/net/wireless/microchip/wilc1000/netdev.c:944 RCU-list traversed in non-reader section!!
[...]
stack backtrace:
CPU: 0 PID: 26 Comm: kworker/0:3 Not tainted 6.8.0-rc1+ #32
Hardware name: Atmel SAMA5
Workqueue: events_freezable mmc_rescan
 unwind_backtrace from show_stack+0x18/0x1c
 show_stack from dump_stack_lvl+0x34/0x58
 dump_stack_lvl from wilc_netdev_ifc_init+0x788/0x8ec
 wilc_netdev_ifc_init from wilc_cfg80211_init+0x690/0x910
 wilc_cfg80211_init from wilc_sdio_probe+0x168/0x490
 wilc_sdio_probe from sdio_bus_probe+0x230/0x3f4
 sdio_bus_probe from really_probe+0x270/0xdf4
 really_probe from __driver_probe_device+0x1dc/0x580
 __driver_probe_device from driver_probe_device+0x60/0x140
 driver_probe_device from __device_attach_driver+0x268/0x364
 __device_attach_driver from bus_for_each_drv+0x15c/0x1cc
 bus_for_each_drv from __device_attach+0x1ec/0x3e8
 __device_attach from bus_probe_device+0x190/0x1c0
 bus_probe_device from device_add+0x10dc/0x18e4
 device_add from sdio_add_func+0x1c0/0x2c0
 sdio_add_func from mmc_attach_sdio+0xa08/0xe1c
 mmc_attach_sdio from mmc_rescan+0xa00/0xfe0
 mmc_rescan from process_one_work+0x8d4/0x169c
 process_one_work from worker_thread+0x8cc/0x1340
 worker_thread from kthread+0x448/0x510
 kthread from ret_from_fork+0x14/0x28

This warning is due to the section being protected by a srcu critical read
section, but the list traversal being done with classic RCU API. Fix the
warning by using corresponding SRCU read lock/unlock APIs. While doing so,
since we always manipulate the same list (managed through a pointer
embedded in struct_wilc), add a macro to reduce the corresponding
boilerplate in each call site.

Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240215-wilc_fix_rcu_usage-v1-2-f610e46c6f82@bootlin.com

diff --git a/drivers/net/wireless/microchip/wilc1000/cfg80211.c b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
index f03fd15c0c97a623ec48c62be3119e5840c9fdc6..33f8e3a419376a4bbe5cfc4d6955aa7663f23702 100644 (file)
--- a/drivers/net/wireless/microchip/wilc1000/cfg80211.c
+++ b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
@@ -1518,7 +1518,7 @@ static struct wilc_vif *wilc_get_vif_from_type(struct wilc *wl, int type)
 {
        struct wilc_vif *vif;
 
-       list_for_each_entry_rcu(vif, &wl->vif_list, list) {
+       wilc_for_each_vif(wl, vif) {
                if (vif->iftype == type)
                        return vif;
        }

diff --git a/drivers/net/wireless/microchip/wilc1000/hif.c b/drivers/net/wireless/microchip/wilc1000/hif.c
index d2b8c26308198ac1c8c4702066bd7d0a298d0051..f3800aa9e9f8a977d9e40a78e188a664379f46dd 100644 (file)
--- a/drivers/net/wireless/microchip/wilc1000/hif.c
+++ b/drivers/net/wireless/microchip/wilc1000/hif.c
@@ -107,7 +107,7 @@ static struct wilc_vif *wilc_get_vif_from_idx(struct wilc *wilc, int idx)
        if (index < 0 || index >= WILC_NUM_CONCURRENT_IFC)
                return NULL;
 
-       list_for_each_entry_rcu(vif, &wilc->vif_list, list) {
+       wilc_for_each_vif(wilc, vif) {
                if (vif->idx == index)
                        return vif;
        }

diff --git a/drivers/net/wireless/microchip/wilc1000/netdev.c b/drivers/net/wireless/microchip/wilc1000/netdev.c
index 62414ab8846e3fda31554b61b9443de6dd0d561f..96f239adc078a498b3f378f9c0aa982ee4e458c3 100644 (file)
--- a/drivers/net/wireless/microchip/wilc1000/netdev.c
+++ b/drivers/net/wireless/microchip/wilc1000/netdev.c
@@ -96,7 +96,7 @@ static struct net_device *get_if_handler(struct wilc *wilc, u8 *mac_header)
        struct wilc_vif *vif;
        struct ieee80211_hdr *h = (struct ieee80211_hdr *)mac_header;
 
-       list_for_each_entry_rcu(vif, &wilc->vif_list, list) {
+       wilc_for_each_vif(wilc, vif) {
                if (vif->iftype == WILC_STATION_MODE)
                        if (ether_addr_equal_unaligned(h->addr2, vif->bssid)) {
                                ndev = vif->ndev;
@@ -132,7 +132,7 @@ int wilc_wlan_get_num_conn_ifcs(struct wilc *wilc)
        struct wilc_vif *vif;
 
        srcu_idx = srcu_read_lock(&wilc->srcu);
-       list_for_each_entry_rcu(vif, &wilc->vif_list, list) {
+       wilc_for_each_vif(wilc, vif) {
                if (!is_zero_ether_addr(vif->bssid))
                        ret_val++;
        }
@@ -146,7 +146,7 @@ static void wilc_wake_tx_queues(struct wilc *wl)
        struct wilc_vif *ifc;
 
        srcu_idx = srcu_read_lock(&wl->srcu);
-       list_for_each_entry_rcu(ifc, &wl->vif_list, list) {
+       wilc_for_each_vif(wl, ifc) {
                if (ifc->mac_opened && netif_queue_stopped(ifc->ndev))
                        netif_wake_queue(ifc->ndev);
        }
@@ -668,7 +668,7 @@ static int wilc_set_mac_addr(struct net_device *dev, void *p)
        /* Verify MAC Address is not already in use: */
 
        srcu_idx = srcu_read_lock(&wilc->srcu);
-       list_for_each_entry_rcu(tmp_vif, &wilc->vif_list, list) {
+       wilc_for_each_vif(wilc, tmp_vif) {
                wilc_get_mac_address(tmp_vif, mac_addr);
                if (ether_addr_equal(addr->sa_data, mac_addr)) {
                        if (vif != tmp_vif) {
@@ -771,7 +771,7 @@ netdev_tx_t wilc_mac_xmit(struct sk_buff *skb, struct net_device *ndev)
                struct wilc_vif *vif;
 
                srcu_idx = srcu_read_lock(&wilc->srcu);
-               list_for_each_entry_rcu(vif, &wilc->vif_list, list) {
+               wilc_for_each_vif(wilc, vif) {
                        if (vif->mac_opened)
                                netif_stop_queue(vif->ndev);
                }
@@ -858,7 +858,7 @@ void wilc_wfi_mgmt_rx(struct wilc *wilc, u8 *buff, u32 size, bool is_auth)
        struct wilc_vif *vif;
 
        srcu_idx = srcu_read_lock(&wilc->srcu);
-       list_for_each_entry_rcu(vif, &wilc->vif_list, list) {
+       wilc_for_each_vif(wilc, vif) {
                struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)buff;
                u16 type = le16_to_cpup((__le16 *)buff);
                u32 type_bit = BIT(type >> 4);
@@ -930,7 +930,7 @@ static u8 wilc_get_available_idx(struct wilc *wl)
        int srcu_idx;
 
        srcu_idx = srcu_read_lock(&wl->srcu);
-       list_for_each_entry_rcu(vif, &wl->vif_list, list) {
+       wilc_for_each_vif(wl, vif) {
                if (vif->idx == 0)
                        idx = 1;
                else

diff --git a/drivers/net/wireless/microchip/wilc1000/netdev.h b/drivers/net/wireless/microchip/wilc1000/netdev.h
index aafe3dc44ac6c2fa3429dd496799f263f32e3e77..5937d6d45695f4d972683c9688bf5637e90bff39 100644 (file)
--- a/drivers/net/wireless/microchip/wilc1000/netdev.h
+++ b/drivers/net/wireless/microchip/wilc1000/netdev.h
@@ -13,6 +13,7 @@
 #include <net/ieee80211_radiotap.h>
 #include <linux/if_arp.h>
 #include <linux/gpio/consumer.h>
+#include <linux/rculist.h>
 
 #include "hif.h"
 #include "wlan.h"
@@ -29,6 +30,11 @@
 
 #define TX_BACKOFF_WEIGHT_MS                   1
 
+#define wilc_for_each_vif(w, v) \
+       struct wilc *_w = w; \
+       list_for_each_entry_srcu(v, &_w->vif_list, list, \
+                                srcu_read_lock_held(&_w->srcu))
+
 struct wilc_wfi_stats {
        unsigned long rx_packets;
        unsigned long tx_packets;

diff --git a/drivers/net/wireless/microchip/wilc1000/wlan.c b/drivers/net/wireless/microchip/wilc1000/wlan.c
index 68be233c36cefba0ef279a86f63fcfcd2f2d3d1f..a9e872a7b2c38b59b55cb617af08d6914970baf5 100644 (file)
--- a/drivers/net/wireless/microchip/wilc1000/wlan.c
+++ b/drivers/net/wireless/microchip/wilc1000/wlan.c
@@ -725,7 +725,7 @@ int wilc_wlan_handle_txq(struct wilc *wilc, u32 *txq_count)
        mutex_lock(&wilc->txq_add_to_head_cs);
 
        srcu_idx = srcu_read_lock(&wilc->srcu);
-       list_for_each_entry_rcu(vif, &wilc->vif_list, list)
+       wilc_for_each_vif(wilc, vif)
                wilc_wlan_txq_filter_dup_tcp_ack(vif->ndev);
        srcu_read_unlock(&wilc->srcu, srcu_idx);