[PATCH] in_interrupt() cleanup, part 2 (wireless)

[PATCH] in_interrupt() cleanup, part 2 (wireless)

[Sebastian Andrzej Siewior]

Folks,

in the discussion about preempt count consistency across kernel configurations:

  https://lore.kernel.org/r/20200914204209.256266093@linutronix.de/

Linus clearly requested that code in drivers and libraries which changes
behaviour based on execution context should either be split up so that
e.g. task context invocations and BH invocations have different interfaces
or if that's not possible the context information has to be provided by the
caller which knows in which context it is executing.

This includes conditional locking, allocation mode (GFP_*) decisions and
avoidance of code paths which might sleep.

In the long run, usage of 'preemptible, in_*irq etc.' should be banned from
driver code completely.

This is part two addressing remaining wireless drivers except for
orinoco-usb.

Sebastian

[PATCH 1/8] orinoco: Remove BUG_ON(in_interrupt/irq())

[Sebastian Andrzej Siewior]

The usage of in_irq()/in_interrupt() in drivers is phased out and the
BUG_ON()'s based on those are not covering all contexts in which these
functions cannot be called.

Aside of that BUG_ON() should only be used as last resort, which is clearly
not the case here.

A broad variety of checks in the invoked functions (always enabled or debug
option dependent) cover these conditions already, so the BUG_ON()'s do not
really provide additional value.

Just remove them.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 drivers/net/wireless/intersil/orinoco/orinoco_usb.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
index b849d27bd741e..046f2453ad5d9 100644
--- a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
+++ b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
@@ -859,8 +859,6 @@ static int ezusb_access_ltv(struct ezusb_priv *upriv,
 	int retval = 0;
 	enum ezusb_state state;
 
-	BUG_ON(in_irq());
-
 	if (!upriv->udev) {
 		retval = -ENODEV;
 		goto exit;
@@ -1349,7 +1347,6 @@ static int ezusb_init(struct hermes *hw)
 	struct ezusb_priv *upriv = hw->priv;
 	int retval;
 
-	BUG_ON(in_interrupt());
 	if (!upriv)
 		return -EINVAL;
 
@@ -1448,7 +1445,6 @@ static inline void ezusb_delete(struct ezusb_priv *upriv)
 	struct list_head *tmp_item;
 	unsigned long flags;
 
-	BUG_ON(in_interrupt());
 	BUG_ON(!upriv);
 
 	mutex_lock(&upriv->mtx);
-- 
2.29.1

[PATCH 2/8] airo: Invoke airo_read_wireless_stats() directly

[Sebastian Andrzej Siewior]

airo_get_wireless_stats() is the iw_handler_if::get_wireless_stats()
callback of this driver. This callback was not allowed to sleep until
commit a160ee69c6a46 ("wext: let get_wireless_stats() sleep") in v2.6.32.

airo still delegates the readout to a thread, which is not longer
necessary.

Invoke airo_read_wireless_stats() directly from the callback and remove
the now unused JOB_WSTATS handling.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 drivers/net/wireless/cisco/airo.c | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
index 87b9398b03fd4..ca423f3b6b3ea 100644
--- a/drivers/net/wireless/cisco/airo.c
+++ b/drivers/net/wireless/cisco/airo.c
@@ -1144,7 +1144,6 @@ static int airo_thread(void *data);
 static void timer_func(struct net_device *dev);
 static int airo_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
 static struct iw_statistics *airo_get_wireless_stats(struct net_device *dev);
-static void airo_read_wireless_stats(struct airo_info *local);
 #ifdef CISCO_EXT
 static int readrids(struct net_device *dev, aironet_ioctl *comp);
 static int writerids(struct net_device *dev, aironet_ioctl *comp);
@@ -1200,7 +1199,6 @@ struct airo_info {
 #define JOB_MIC	5
 #define JOB_EVENT	6
 #define JOB_AUTOWEP	7
-#define JOB_WSTATS	8
 #define JOB_SCAN_RESULTS  9
 	unsigned long jobs;
 	int (*bap_read)(struct airo_info*, __le16 *pu16Dst, int bytelen,
@@ -3155,8 +3153,6 @@ static int airo_thread(void *data)
 			airo_end_xmit11(dev);
 		else if (test_bit(JOB_STATS, &ai->jobs))
 			airo_read_stats(dev);
-		else if (test_bit(JOB_WSTATS, &ai->jobs))
-			airo_read_wireless_stats(ai);
 		else if (test_bit(JOB_PROMISC, &ai->jobs))
 			airo_set_promisc(ai);
 		else if (test_bit(JOB_MIC, &ai->jobs))
@@ -7732,15 +7728,12 @@ static void airo_read_wireless_stats(struct airo_info *local)
 	__le32 *vals = stats_rid.vals;
 
 	/* Get stats out of the card */
-	clear_bit(JOB_WSTATS, &local->jobs);
-	if (local->power.event) {
-		up(&local->sem);
+	if (local->power.event)
 		return;
-	}
+
 	readCapabilityRid(local, &cap_rid, 0);
 	readStatusRid(local, &status_rid, 0);
 	readStatsRid(local, &stats_rid, RID_STATS, 0);
-	up(&local->sem);
 
 	/* The status */
 	local->wstats.status = le16_to_cpu(status_rid.mode);
@@ -7783,15 +7776,10 @@ static struct iw_statistics *airo_get_wireless_stats(struct net_device *dev)
 {
 	struct airo_info *local =  dev->ml_priv;
 
-	if (!test_bit(JOB_WSTATS, &local->jobs)) {
-		/* Get stats out of the card if available */
-		if (down_trylock(&local->sem) != 0) {
-			set_bit(JOB_WSTATS, &local->jobs);
-			wake_up_interruptible(&local->thr_wait);
-		} else
-			airo_read_wireless_stats(local);
+	if (!down_interruptible(&local->sem)) {
+		airo_read_wireless_stats(local);
+		up(&local->sem);
 	}
-
 	return &local->wstats;
 }
 
-- 
2.29.1

[PATCH 3/8] airo: Always use JOB_STATS and JOB_EVENT

[Sebastian Andrzej Siewior]

issuecommand() is using in_atomic() to decide if it is safe to invoke
schedule() while waiting for the command to be accepted.

Usage of in_atomic() for this is only half correct as it can not detect all
condition where it is not allowed to schedule(). Also Linus clearly
requested that code which changes behaviour depending on context should
either be seperated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

Chasing the call chains leading up to issuecommand() is straight forward,
but airo_link() and airo_get_stats() would require to pass the context
through a quite large amount of functions.

As this is ancient hardware, avoid the churn and enforce the invocation of
those functions through the JOB machinery.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 drivers/net/wireless/cisco/airo.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
index ca423f3b6b3ea..369a6ca44d1ff 100644
--- a/drivers/net/wireless/cisco/airo.c
+++ b/drivers/net/wireless/cisco/airo.c
@@ -2286,12 +2286,8 @@ static struct net_device_stats *airo_get_stats(struct net_device *dev)
 	struct airo_info *local =  dev->ml_priv;
 
 	if (!test_bit(JOB_STATS, &local->jobs)) {
-		/* Get stats out of the card if available */
-		if (down_trylock(&local->sem) != 0) {
-			set_bit(JOB_STATS, &local->jobs);
-			wake_up_interruptible(&local->thr_wait);
-		} else
-			airo_read_stats(dev);
+		set_bit(JOB_STATS, &local->jobs);
+		wake_up_interruptible(&local->thr_wait);
 	}
 
 	return &dev->stats;
@@ -3277,11 +3273,9 @@ static void airo_handle_link(struct airo_info *ai)
 		set_bit(FLAG_UPDATE_UNI, &ai->flags);
 		set_bit(FLAG_UPDATE_MULTI, &ai->flags);
 
-		if (down_trylock(&ai->sem) != 0) {
-			set_bit(JOB_EVENT, &ai->jobs);
-			wake_up_interruptible(&ai->thr_wait);
-		} else
-			airo_send_event(ai->dev);
+		set_bit(JOB_EVENT, &ai->jobs);
+		wake_up_interruptible(&ai->thr_wait);
+
 		netif_carrier_on(ai->dev);
 	} else if (!scan_forceloss) {
 		if (auto_wep && !ai->expires) {
-- 
2.29.1

[PATCH 4/8] airo: Replace in_atomic() usage.

[Sebastian Andrzej Siewior]

issuecommand() is using in_atomic() to decide if it is safe to invoke
schedule() while waiting for the command to be accepted.

Usage of in_atomic() for this is only half correct as it can not detect all
condition where it is not allowed to schedule(). Also Linus clearly
requested that code which changes behaviour depending on context should
either be seperated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

Add an may_sleep argument to issuecommand() indicating when it is save to
sleep and change schedule() to cond_resched() because it's pointless to
invoke schedule() if there is no request to reschedule.

Pass the may_sleep condition through the various call chains leading to
issuecommand().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 drivers/net/wireless/cisco/airo.c | 86 +++++++++++++++++--------------
 1 file changed, 47 insertions(+), 39 deletions(-)

diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
index 369a6ca44d1ff..74acf9af2adb1 100644
--- a/drivers/net/wireless/cisco/airo.c
+++ b/drivers/net/wireless/cisco/airo.c
@@ -1115,7 +1115,8 @@ static int enable_MAC(struct airo_info *ai, int lock);
 static void disable_MAC(struct airo_info *ai, int lock);
 static void enable_interrupts(struct airo_info*);
 static void disable_interrupts(struct airo_info*);
-static u16 issuecommand(struct airo_info*, Cmd *pCmd, Resp *pRsp);
+static u16 issuecommand(struct airo_info*, Cmd *pCmd, Resp *pRsp,
+			bool may_sleep);
 static int bap_setup(struct airo_info*, u16 rid, u16 offset, int whichbap);
 static int aux_bap_read(struct airo_info*, __le16 *pu16Dst, int bytelen,
 			int whichbap);
@@ -1130,8 +1131,10 @@ static int PC4500_writerid(struct airo_info*, u16 rid, const void
 static int do_writerid(struct airo_info*, u16 rid, const void *rid_data,
 			int len, int dummy);
 static u16 transmit_allocate(struct airo_info*, int lenPayload, int raw);
-static int transmit_802_3_packet(struct airo_info*, int len, char *pPacket);
-static int transmit_802_11_packet(struct airo_info*, int len, char *pPacket);
+static int transmit_802_3_packet(struct airo_info*, int len, char *pPacket,
+				 bool may_sleep);
+static int transmit_802_11_packet(struct airo_info*, int len, char *pPacket,
+				  bool may_sleep);
 
 static int mpi_send_packet(struct net_device *dev);
 static void mpi_unmap_card(struct pci_dev *pci);
@@ -1753,7 +1756,7 @@ static int readBSSListRid(struct airo_info *ai, int first,
 		if (down_interruptible(&ai->sem))
 			return -ERESTARTSYS;
 		ai->list_bss_task = current;
-		issuecommand(ai, &cmd, &rsp);
+		issuecommand(ai, &cmd, &rsp, true);
 		up(&ai->sem);
 		/* Let the command take effect */
 		schedule_timeout_uninterruptible(3 * HZ);
@@ -2096,7 +2099,7 @@ static void get_tx_error(struct airo_info *ai, s32 fid)
 	}
 }
 
-static void airo_end_xmit(struct net_device *dev)
+static void airo_end_xmit(struct net_device *dev, bool may_sleep)
 {
 	u16 status;
 	int i;
@@ -2107,7 +2110,7 @@ static void airo_end_xmit(struct net_device *dev)
 
 	clear_bit(JOB_XMIT, &priv->jobs);
 	clear_bit(FLAG_PENDING_XMIT, &priv->flags);
-	status = transmit_802_3_packet (priv, fids[fid], skb->data);
+	status = transmit_802_3_packet(priv, fids[fid], skb->data, may_sleep);
 	up(&priv->sem);
 
 	i = 0;
@@ -2164,11 +2167,11 @@ static netdev_tx_t airo_start_xmit(struct sk_buff *skb,
 		set_bit(JOB_XMIT, &priv->jobs);
 		wake_up_interruptible(&priv->thr_wait);
 	} else
-		airo_end_xmit(dev);
+		airo_end_xmit(dev, false);
 	return NETDEV_TX_OK;
 }
 
-static void airo_end_xmit11(struct net_device *dev)
+static void airo_end_xmit11(struct net_device *dev, bool may_sleep)
 {
 	u16 status;
 	int i;
@@ -2179,7 +2182,7 @@ static void airo_end_xmit11(struct net_device *dev)
 
 	clear_bit(JOB_XMIT11, &priv->jobs);
 	clear_bit(FLAG_PENDING_XMIT11, &priv->flags);
-	status = transmit_802_11_packet (priv, fids[fid], skb->data);
+	status = transmit_802_11_packet(priv, fids[fid], skb->data, may_sleep);
 	up(&priv->sem);
 
 	i = MAX_FIDS / 2;
@@ -2243,7 +2246,7 @@ static netdev_tx_t airo_start_xmit11(struct sk_buff *skb,
 		set_bit(JOB_XMIT11, &priv->jobs);
 		wake_up_interruptible(&priv->thr_wait);
 	} else
-		airo_end_xmit11(dev);
+		airo_end_xmit11(dev, false);
 	return NETDEV_TX_OK;
 }
 
@@ -2293,7 +2296,7 @@ static struct net_device_stats *airo_get_stats(struct net_device *dev)
 	return &dev->stats;
 }
 
-static void airo_set_promisc(struct airo_info *ai)
+static void airo_set_promisc(struct airo_info *ai, bool may_sleep)
 {
 	Cmd cmd;
 	Resp rsp;
@@ -2302,7 +2305,7 @@ static void airo_set_promisc(struct airo_info *ai)
 	cmd.cmd = CMD_SETMODE;
 	clear_bit(JOB_PROMISC, &ai->jobs);
 	cmd.parm0=(ai->flags&IFF_PROMISC) ? PROMISC : NOPROMISC;
-	issuecommand(ai, &cmd, &rsp);
+	issuecommand(ai, &cmd, &rsp, may_sleep);
 	up(&ai->sem);
 }
 
@@ -2316,7 +2319,7 @@ static void airo_set_multicast_list(struct net_device *dev)
 			set_bit(JOB_PROMISC, &ai->jobs);
 			wake_up_interruptible(&ai->thr_wait);
 		} else
-			airo_set_promisc(ai);
+			airo_set_promisc(ai, false);
 	}
 
 	if ((dev->flags&IFF_ALLMULTI) || !netdev_mc_empty(dev)) {
@@ -2476,7 +2479,7 @@ static int mpi_init_descriptors (struct airo_info *ai)
 	cmd.parm0 = FID_RX;
 	cmd.parm1 = (ai->rxfids[0].card_ram_off - ai->pciaux);
 	cmd.parm2 = MPI_MAX_FIDS;
-	rc = issuecommand(ai, &cmd, &rsp);
+	rc = issuecommand(ai, &cmd, &rsp, true);
 	if (rc != SUCCESS) {
 		airo_print_err(ai->dev->name, "Couldn't allocate RX FID");
 		return rc;
@@ -2504,7 +2507,7 @@ static int mpi_init_descriptors (struct airo_info *ai)
 	}
 	ai->txfids[i-1].tx_desc.eoc = 1; /* Last descriptor has EOC set */
 
-	rc = issuecommand(ai, &cmd, &rsp);
+	rc = issuecommand(ai, &cmd, &rsp, true);
 	if (rc != SUCCESS) {
 		airo_print_err(ai->dev->name, "Couldn't allocate TX FID");
 		return rc;
@@ -2518,7 +2521,7 @@ static int mpi_init_descriptors (struct airo_info *ai)
 	cmd.parm0 = RID_RW;
 	cmd.parm1 = (ai->config_desc.card_ram_off - ai->pciaux);
 	cmd.parm2 = 1; /* Magic number... */
-	rc = issuecommand(ai, &cmd, &rsp);
+	rc = issuecommand(ai, &cmd, &rsp, true);
 	if (rc != SUCCESS) {
 		airo_print_err(ai->dev->name, "Couldn't allocate RID");
 		return rc;
@@ -3144,13 +3147,13 @@ static int airo_thread(void *data)
 		}
 
 		if (test_bit(JOB_XMIT, &ai->jobs))
-			airo_end_xmit(dev);
+			airo_end_xmit(dev, true);
 		else if (test_bit(JOB_XMIT11, &ai->jobs))
-			airo_end_xmit11(dev);
+			airo_end_xmit11(dev, true);
 		else if (test_bit(JOB_STATS, &ai->jobs))
 			airo_read_stats(dev);
 		else if (test_bit(JOB_PROMISC, &ai->jobs))
-			airo_set_promisc(ai);
+			airo_set_promisc(ai, true);
 		else if (test_bit(JOB_MIC, &ai->jobs))
 			micinit(ai);
 		else if (test_bit(JOB_EVENT, &ai->jobs))
@@ -3599,7 +3602,7 @@ static int enable_MAC(struct airo_info *ai, int lock)
 	if (!test_bit(FLAG_ENABLED, &ai->flags)) {
 		memset(&cmd, 0, sizeof(cmd));
 		cmd.cmd = MAC_ENABLE;
-		rc = issuecommand(ai, &cmd, &rsp);
+		rc = issuecommand(ai, &cmd, &rsp, true);
 		if (rc == SUCCESS)
 			set_bit(FLAG_ENABLED, &ai->flags);
 	} else
@@ -3631,7 +3634,7 @@ static void disable_MAC(struct airo_info *ai, int lock)
 			netif_carrier_off(ai->dev);
 		memset(&cmd, 0, sizeof(cmd));
 		cmd.cmd = MAC_DISABLE; // disable in case already enabled
-		issuecommand(ai, &cmd, &rsp);
+		issuecommand(ai, &cmd, &rsp, true);
 		clear_bit(FLAG_ENABLED, &ai->flags);
 	}
 	if (lock == 1)
@@ -3834,7 +3837,7 @@ static u16 setup_card(struct airo_info *ai, u8 *mac, int lock)
 	cmd.parm0 = cmd.parm1 = cmd.parm2 = 0;
 	if (lock && down_interruptible(&ai->sem))
 		return ERROR;
-	if (issuecommand(ai, &cmd, &rsp) != SUCCESS) {
+	if (issuecommand(ai, &cmd, &rsp, true) != SUCCESS) {
 		if (lock)
 			up(&ai->sem);
 		return ERROR;
@@ -3844,7 +3847,7 @@ static u16 setup_card(struct airo_info *ai, u8 *mac, int lock)
 	// Let's figure out if we need to use the AUX port
 	if (!test_bit(FLAG_MPI,&ai->flags)) {
 		cmd.cmd = CMD_ENABLEAUX;
-		if (issuecommand(ai, &cmd, &rsp) != SUCCESS) {
+		if (issuecommand(ai, &cmd, &rsp, true) != SUCCESS) {
 			if (lock)
 				up(&ai->sem);
 			airo_print_err(ai->dev->name, "Error checking for AUX port");
@@ -3956,7 +3959,8 @@ static u16 setup_card(struct airo_info *ai, u8 *mac, int lock)
 	return SUCCESS;
 }
 
-static u16 issuecommand(struct airo_info *ai, Cmd *pCmd, Resp *pRsp)
+static u16 issuecommand(struct airo_info *ai, Cmd *pCmd, Resp *pRsp,
+			bool may_sleep)
 {
         // Im really paranoid about letting it run forever!
 	int max_tries = 600000;
@@ -3973,8 +3977,8 @@ static u16 issuecommand(struct airo_info *ai, Cmd *pCmd, Resp *pRsp)
 		if ((IN4500(ai, COMMAND)) == pCmd->cmd)
 			// PC4500 didn't notice command, try again
 			OUT4500(ai, COMMAND, pCmd->cmd);
-		if (!in_atomic() && (max_tries & 255) == 0)
-			schedule();
+		if (may_sleep && (max_tries & 255) == 0)
+			cond_resched();
 	}
 
 	if (max_tries == -1) {
@@ -4131,7 +4135,7 @@ static int PC4500_accessrid(struct airo_info *ai, u16 rid, u16 accmd)
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.cmd = accmd;
 	cmd.parm0 = rid;
-	status = issuecommand(ai, &cmd, &rsp);
+	status = issuecommand(ai, &cmd, &rsp, true);
 	if (status != 0) return status;
 	if ((rsp.status & 0x7F00) != 0) {
 		return (accmd << 8) + (rsp.rsp0 & 0xFF);
@@ -4167,7 +4171,7 @@ static int PC4500_readrid(struct airo_info *ai, u16 rid, void *pBuf, int len, in
 		memcpy_toio(ai->config_desc.card_ram_off,
 			&ai->config_desc.rid_desc, sizeof(Rid));
 
-		rc = issuecommand(ai, &cmd, &rsp);
+		rc = issuecommand(ai, &cmd, &rsp, true);
 
 		if (rsp.status & 0x7f00)
 			rc = rsp.rsp0;
@@ -4246,7 +4250,7 @@ static int PC4500_writerid(struct airo_info *ai, u16 rid,
 			memcpy(ai->config_desc.virtual_host_addr,
 				pBuf, len);
 
-			rc = issuecommand(ai, &cmd, &rsp);
+			rc = issuecommand(ai, &cmd, &rsp, true);
 			if ((rc & 0xff00) != 0) {
 				airo_print_err(ai->dev->name, "%s: Write rid Error %d",
 						__func__, rc);
@@ -4292,7 +4296,7 @@ static u16 transmit_allocate(struct airo_info *ai, int lenPayload, int raw)
 	cmd.parm0 = lenPayload;
 	if (down_interruptible(&ai->sem))
 		return ERROR;
-	if (issuecommand(ai, &cmd, &rsp) != SUCCESS) {
+	if (issuecommand(ai, &cmd, &rsp, true) != SUCCESS) {
 		txFid = ERROR;
 		goto done;
 	}
@@ -4338,7 +4342,8 @@ static u16 transmit_allocate(struct airo_info *ai, int lenPayload, int raw)
 /* In general BAP1 is dedicated to transmiting packets.  However,
    since we need a BAP when accessing RIDs, we also use BAP1 for that.
    Make sure the BAP1 spinlock is held when this is called. */
-static int transmit_802_3_packet(struct airo_info *ai, int len, char *pPacket)
+static int transmit_802_3_packet(struct airo_info *ai, int len, char *pPacket,
+				 bool may_sleep)
 {
 	__le16 payloadLen;
 	Cmd cmd;
@@ -4376,12 +4381,14 @@ static int transmit_802_3_packet(struct airo_info *ai, int len, char *pPacket)
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.cmd = CMD_TRANSMIT;
 	cmd.parm0 = txFid;
-	if (issuecommand(ai, &cmd, &rsp) != SUCCESS) return ERROR;
+	if (issuecommand(ai, &cmd, &rsp, may_sleep) != SUCCESS)
+		return ERROR;
 	if ((rsp.status & 0xFF00) != 0) return ERROR;
 	return SUCCESS;
 }
 
-static int transmit_802_11_packet(struct airo_info *ai, int len, char *pPacket)
+static int transmit_802_11_packet(struct airo_info *ai, int len, char *pPacket,
+				  bool may_sleep)
 {
 	__le16 fc, payloadLen;
 	Cmd cmd;
@@ -4416,7 +4423,8 @@ static int transmit_802_11_packet(struct airo_info *ai, int len, char *pPacket)
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.cmd = CMD_TRANSMIT;
 	cmd.parm0 = txFid;
-	if (issuecommand(ai, &cmd, &rsp) != SUCCESS) return ERROR;
+	if (issuecommand(ai, &cmd, &rsp, may_sleep) != SUCCESS)
+		return ERROR;
 	if ((rsp.status & 0xFF00) != 0) return ERROR;
 	return SUCCESS;
 }
@@ -5480,7 +5488,7 @@ static int proc_BSSList_open(struct inode *inode, struct file *file)
 				kfree(file->private_data);
 				return -ERESTARTSYS;
 			}
-			issuecommand(ai, &cmd, &rsp);
+			issuecommand(ai, &cmd, &rsp, true);
 			up(&ai->sem);
 			data->readlen = 0;
 			return 0;
@@ -5617,7 +5625,7 @@ static int __maybe_unused airo_pci_suspend(struct device *dev_d)
 	netif_device_detach(dev);
 	ai->power = PMSG_SUSPEND;
 	cmd.cmd = HOSTSLEEP;
-	issuecommand(ai, &cmd, &rsp);
+	issuecommand(ai, &cmd, &rsp, true);
 
 	device_wakeup_enable(dev_d);
 	return 0;
@@ -5960,7 +5968,7 @@ static int airo_set_wap(struct net_device *dev,
 		cmd.cmd = CMD_LOSE_SYNC;
 		if (down_interruptible(&local->sem))
 			return -ERESTARTSYS;
-		issuecommand(local, &cmd, &rsp);
+		issuecommand(local, &cmd, &rsp, true);
 		up(&local->sem);
 	} else {
 		memset(APList_rid, 0, sizeof(*APList_rid));
@@ -7258,7 +7266,7 @@ static int airo_set_scan(struct net_device *dev,
 	ai->scan_timeout = RUN_AT(3*HZ);
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.cmd = CMD_LISTBSS;
-	issuecommand(ai, &cmd, &rsp);
+	issuecommand(ai, &cmd, &rsp, true);
 	wake = 1;
 
 out:
@@ -7525,7 +7533,7 @@ static int airo_config_commit(struct net_device *dev,
 	writeConfigRid(local, 0);
 	enable_MAC(local, 0);
 	if (test_bit (FLAG_RESET, &local->flags))
-		airo_set_promisc(local);
+		airo_set_promisc(local, true);
 	else
 		up(&local->sem);
 
-- 
2.29.1

[PATCH 5/8] hostap: Remove in_atomic() check.

[Sebastian Andrzej Siewior]

hostap_get_wireless_stats() is the iw_handler_if::get_wireless_stats()
callback of this driver. This callback was not allowed to sleep until
commit a160ee69c6a46 ("wext: let get_wireless_stats() sleep") in v2.6.32.

Remove the therefore pointless in_atomic() check.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Jouni Malinen <j@w1.fi>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 drivers/net/wireless/intersil/hostap/hostap_ioctl.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/net/wireless/intersil/hostap/hostap_ioctl.c b/drivers/net/wireless/intersil/hostap/hostap_ioctl.c
index 514c7b01dbf6f..49766b285230c 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_ioctl.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_ioctl.c
@@ -44,19 +44,8 @@ static struct iw_statistics *hostap_get_wireless_stats(struct net_device *dev)
 
 	if (local->iw_mode != IW_MODE_MASTER &&
 	    local->iw_mode != IW_MODE_REPEAT) {
-		int update = 1;
-#ifdef in_atomic
-		/* RID reading might sleep and it must not be called in
-		 * interrupt context or while atomic. However, this
-		 * function seems to be called while atomic (at least in Linux
-		 * 2.5.59). Update signal quality values only if in suitable
-		 * context. Otherwise, previous values read from tick timer
-		 * will be used. */
-		if (in_atomic())
-			update = 0;
-#endif /* in_atomic */
 
-		if (update && prism2_update_comms_qual(dev) == 0)
+		if (prism2_update_comms_qual(dev) == 0)
 			wstats->qual.updated = IW_QUAL_ALL_UPDATED |
 				IW_QUAL_DBM;
 
-- 
2.29.1

[PATCH 6/8] zd1211rw: Remove in_atomic() usage.

[Sebastian Andrzej Siewior]

The usage of in_atomic() in driver code is deprecated as it can not
always detect all states where it is not allowed to sleep.

All callers are in premptible thread context and all functions invoke core
functions which have checks for invalid calling contexts already.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Ulrich Kunitz <kune@deine-taler.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 drivers/net/wireless/zydas/zd1211rw/zd_usb.c | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/drivers/net/wireless/zydas/zd1211rw/zd_usb.c b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
index 66367ab7e4c1e..5c4cd0e1adebb 100644
--- a/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
+++ b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
@@ -1711,11 +1711,6 @@ int zd_usb_ioread16v(struct zd_usb *usb, u16 *values,
 			 count, USB_MAX_IOREAD16_COUNT);
 		return -EINVAL;
 	}
-	if (in_atomic()) {
-		dev_dbg_f(zd_usb_dev(usb),
-			 "error: io in atomic context not supported\n");
-		return -EWOULDBLOCK;
-	}
 	if (!usb_int_enabled(usb)) {
 		dev_dbg_f(zd_usb_dev(usb),
 			  "error: usb interrupt not enabled\n");
@@ -1882,11 +1877,6 @@ int zd_usb_iowrite16v_async(struct zd_usb *usb, const struct zd_ioreq16 *ioreqs,
 			count, USB_MAX_IOWRITE16_COUNT);
 		return -EINVAL;
 	}
-	if (in_atomic()) {
-		dev_dbg_f(zd_usb_dev(usb),
-			"error: io in atomic context not supported\n");
-		return -EWOULDBLOCK;
-	}
 
 	udev = zd_usb_to_usbdev(usb);
 
@@ -1966,11 +1956,6 @@ int zd_usb_rfwrite(struct zd_usb *usb, u32 value, u8 bits)
 	int i, req_len, actual_req_len;
 	u16 bit_value_template;
 
-	if (in_atomic()) {
-		dev_dbg_f(zd_usb_dev(usb),
-			"error: io in atomic context not supported\n");
-		return -EWOULDBLOCK;
-	}
 	if (bits < USB_MIN_RFWRITE_BIT_COUNT) {
 		dev_dbg_f(zd_usb_dev(usb),
 			"error: bits %d are smaller than"
-- 
2.29.1

[PATCH 7/8] rtlwifi: Remove in_interrupt() usage in is_any_client_connect_to_ap().

[Sebastian Andrzej Siewior]

is_any_client_connect_to_ap() is using in_interrupt() to determine whether
it should acquire the lock prior accessing the list.

The usage of in_interrupt() in drivers is phased out and Linus clearly
requested that code which changes behaviour depending on context should
either be separated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

The function is called from:

    - halbtc_get()

    - halbtc_get()
        halbtc_get_wifi_link_status()

    - halbtc_display_dbg_msg()
	halbtc_display_wifi_status()
          halbtc_get_wifi_link_status()

All top level callers are part of the btc_coexist callback inferface and
are never invoked from a context which can hold the lock already.

The contexts which hold the lock are either protecting list add/del
operations or list walks which never call into any of the btc_coexist
interfaces.

In fact the conditional is outright dangerous because if this function
would be invoked from a BH disabled context the check would avoid taking
the lock while on another CPU the list could be manipulated under the lock.

Remove the in_interrupt() check and always acquire the lock.

To simplify the code further use list_empty() instead of walking the list
and counting the entries just to check the count for > 0 at the end.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 .../realtek/rtlwifi/btcoexist/halbtcoutsrc.c  | 25 +++++--------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c b/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c
index 2c05369b79e4d..2155a6699ef8d 100644
--- a/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c
+++ b/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c
@@ -47,30 +47,17 @@ static bool is_any_client_connect_to_ap(struct btc_coexist *btcoexist)
 {
 	struct rtl_priv *rtlpriv = btcoexist->adapter;
 	struct rtl_mac *mac = rtl_mac(rtlpriv);
-	struct rtl_sta_info *drv_priv;
-	u8 cnt = 0;
+	bool ret = false;
 
 	if (mac->opmode == NL80211_IFTYPE_ADHOC ||
 	    mac->opmode == NL80211_IFTYPE_MESH_POINT ||
 	    mac->opmode == NL80211_IFTYPE_AP) {
-		if (in_interrupt() > 0) {
-			list_for_each_entry(drv_priv, &rtlpriv->entry_list,
-					    list) {
-				cnt++;
-			}
-		} else {
-			spin_lock_bh(&rtlpriv->locks.entry_list_lock);
-			list_for_each_entry(drv_priv, &rtlpriv->entry_list,
-					    list) {
-				cnt++;
-			}
-			spin_unlock_bh(&rtlpriv->locks.entry_list_lock);
-		}
+		spin_lock_bh(&rtlpriv->locks.entry_list_lock);
+		if (!list_empty(&rtlpriv->entry_list))
+			ret = true;
+		spin_unlock_bh(&rtlpriv->locks.entry_list_lock);
 	}
-	if (cnt > 0)
-		return true;
-	else
-		return false;
+	return ret;
 }
 
 static bool halbtc_legacy(struct rtl_priv *adapter)
-- 
2.29.1

[PATCH 8/8] rtlwifi: Remove in_interrupt() usage in halbtc_send_bt_mp_operation()

[Sebastian Andrzej Siewior]

halbtc_send_bt_mp_operation() uses in_interrupt() to determine if it is
safe to invoke wait_for_completion().

The usage of in_interrupt() in drivers is phased out and Linus clearly
requested that code which changes behaviour depending on context should
either be separated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

Aside of that in_interrupt() is not correct as it does not catch preempt
disabled regions which neither can sleep.

halbtc_send_bt_mp_operation() is called from:

 rtl_watchdog_wq_callback()
   rtl_btc_periodical()
     halbtc_get()
       case BTC_GET_U4_BT_PATCH_VER:
         halbtc_get_bt_patch_version()

 which is preemtible context.

   rtl_c2h_content_parsing()
     btc_ops->btc_btinfo_notify()
       rtl_btc_btinfo_notify()
         exhalbtc_bt_info_notify()
           ex_btc8723b1ant_bt_info_notify()
	   ex_btc8821a1ant_bt_info_notify()
	   ex_btc8821a2ant_bt_info_notify()
             btcoexist->btc_set_bt_reg()
               halbtc_set_bt_reg()

   rtl_c2h_content_parsing() is in turn called from:

   rtl_c2hcmd_wq_callback()
     rtl_c2hcmd_launcher()

   which is preemptible context and from:

   _rtl_pci_rx_interrupt
     rtl_c2hcmd_enqueue()

   which is obviously not preemptible but limited to C2H_BT_MP commands
   which does invoke rtl_c2h_content_parsing().

Aside of that it can be reached from:

     halbtc_get()
       case BTC_GET_U4_SUPPORTED_FEATURE:
         halbtc_get_bt_coex_supported_feature()
       case BTC_GET_U4_BT_FORBIDDEN_SLOT_VAL:
         halbtc_get_bt_forbidden_slot_val()
       case BTC_GET_U4_BT_DEVICE_INFO:
         halbtc_get_bt_device_info()
       case BTC_GET_U4_SUPPORTED_VERSION:
         halbtc_get_bt_coex_supported_version()
       case BTC_GET_U4_SUPPORTED_FEATURE:
         halbtc_get_bt_coex_supported_feature()

   btcoexist->btc_get_bt_afh_map_from_bt()
     halbtc_get_bt_afh_map_from_bt()

   btcoexist->btc_get_ble_scan_para_from_bt()
     halbtc_get_ble_scan_para_from_bt()

   btcoexist->btc_get_ble_scan_type_from_bt()
     halbtc_get_ble_scan_type_from_bt()

   btcoexist->btc_get_ant_det_val_from_bt()
     halbtc_get_ant_det_val_from_bt()

   btcoexist->btc_get_bt_coex_supported_version()
     halbtc_get_bt_coex_supported_version()

   btcoexist->btc_get_bt_coex_supported_feature()
     halbtc_get_bt_coex_supported_feature()

None of these have a caller. Welcome to the wonderful world of HALs and
onion layers.

Remove in_interrupt() check.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
---
 drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c b/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c
index 2155a6699ef8d..be4c0e60d44d1 100644
--- a/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c
+++ b/drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c
@@ -240,9 +240,6 @@ bool halbtc_send_bt_mp_operation(struct btc_coexist *btcoexist, u8 op_code,
 	rtl_dbg(rtlpriv, COMP_BT_COEXIST, DBG_LOUD,
 		"btmpinfo wait req_num=%d wait=%ld\n", req_num, wait_ms);
 
-	if (in_interrupt())
-		return false;
-
 	if (wait_for_completion_timeout(&btcoexist->bt_mp_comp,
 					msecs_to_jiffies(wait_ms)) == 0) {
 		rtl_dbg(rtlpriv, COMP_BT_COEXIST, DBG_DMESG,
-- 
2.29.1

Re: [PATCH 1/8] orinoco: Remove BUG_ON(in_interrupt/irq())

[Kalle Valo]

Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> The usage of in_irq()/in_interrupt() in drivers is phased out and the
> BUG_ON()'s based on those are not covering all contexts in which these
> functions cannot be called.
> 
> Aside of that BUG_ON() should only be used as last resort, which is clearly
> not the case here.
> 
> A broad variety of checks in the invoked functions (always enabled or debug
> option dependent) cover these conditions already, so the BUG_ON()'s do not
> really provide additional value.
> 
> Just remove them.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: Kalle Valo <kvalo@codeaurora.org>
> Cc: linux-wireless@vger.kernel.org

8 patches applied to wireless-drivers-next.git, thanks.

ce4dd05cbba6 orinoco: Remove BUG_ON(in_interrupt/irq())
24bf941f2c96 airo: Invoke airo_read_wireless_stats() directly
49eb01995285 airo: Always use JOB_STATS and JOB_EVENT
494e46d08d35 airo: Replace in_atomic() usage.
7534fd5e5834 hostap: Remove in_atomic() check.
abcda807d868 zd1211rw: Remove in_atomic() usage.
317f688b0a54 rtlwifi: Remove in_interrupt() usage in is_any_client_connect_to_ap().
50c61ae15865 rtlwifi: Remove in_interrupt() usage in halbtc_send_bt_mp_operation()

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20201101211536.2966644-2-bigeasy@linutronix.de/

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