locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()

Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

7 files changed, 16 insertions, 16 deletions

diff --git a/drivers/net/wireless/ath/ath5k/desc.c b/drivers/net/wireless/ath/ath5k/desc.c
index bd8d4392d68b..80f75139495f 100644
--- a/drivers/net/wireless/ath/ath5k/desc.c
+++ b/drivers/net/wireless/ath/ath5k/desc.c
@@ -500,13 +500,13 @@ ath5k_hw_proc_4word_tx_status(struct ath5k_hw *ah,
 
 	tx_status = &desc->ud.ds_tx5212.tx_stat;
 
-	txstat1 = ACCESS_ONCE(tx_status->tx_status_1);
+	txstat1 = READ_ONCE(tx_status->tx_status_1);
 
 	/* No frame has been send or error */
 	if (unlikely(!(txstat1 & AR5K_DESC_TX_STATUS1_DONE)))
 		return -EINPROGRESS;
 
-	txstat0 = ACCESS_ONCE(tx_status->tx_status_0);
+	txstat0 = READ_ONCE(tx_status->tx_status_0);
 
 	/*
 	 * Get descriptor status
@@ -700,14 +700,14 @@ ath5k_hw_proc_5212_rx_status(struct ath5k_hw *ah,
 	u32 rxstat0, rxstat1;
 
 	rx_status = &desc->ud.ds_rx.rx_stat;
-	rxstat1 = ACCESS_ONCE(rx_status->rx_status_1);
+	rxstat1 = READ_ONCE(rx_status->rx_status_1);
 
 	/* No frame received / not ready */
 	if (unlikely(!(rxstat1 & AR5K_5212_RX_DESC_STATUS1_DONE)))
 		return -EINPROGRESS;
 
 	memset(rs, 0, sizeof(struct ath5k_rx_status));
-	rxstat0 = ACCESS_ONCE(rx_status->rx_status_0);
+	rxstat0 = READ_ONCE(rx_status->rx_status_0);
 
 	/*
 	 * Frame receive status
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
index 613caca7dc02..785a0f33b7e6 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
@@ -3628,7 +3628,7 @@ static void brcmf_sdio_dataworker(struct work_struct *work)
 
 	bus->dpc_running = true;
 	wmb();
-	while (ACCESS_ONCE(bus->dpc_triggered)) {
+	while (READ_ONCE(bus->dpc_triggered)) {
 		bus->dpc_triggered = false;
 		brcmf_sdio_dpc(bus);
 		bus->idlecount = 0;
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
index 231878969332..0f45f34e39d3 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
@@ -1118,7 +1118,7 @@ void iwl_mvm_set_hw_ctkill_state(struct iwl_mvm *mvm, bool state)
 static bool iwl_mvm_set_hw_rfkill_state(struct iwl_op_mode *op_mode, bool state)
 {
 	struct iwl_mvm *mvm = IWL_OP_MODE_GET_MVM(op_mode);
-	bool calibrating = ACCESS_ONCE(mvm->calibrating);
+	bool calibrating = READ_ONCE(mvm->calibrating);
 
 	if (state)
 		set_bit(IWL_MVM_STATUS_HW_RFKILL, &mvm->status);
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
index 6f2e2af23219..6e9d3289b9d0 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
@@ -652,7 +652,7 @@ int iwl_mvm_tx_skb_non_sta(struct iwl_mvm *mvm, struct sk_buff *skb)
 				return -1;
 		} else if (info.control.vif->type == NL80211_IFTYPE_STATION &&
 			   is_multicast_ether_addr(hdr->addr1)) {
-			u8 ap_sta_id = ACCESS_ONCE(mvmvif->ap_sta_id);
+			u8 ap_sta_id = READ_ONCE(mvmvif->ap_sta_id);
 
 			if (ap_sta_id != IWL_MVM_INVALID_STA)
 				sta_id = ap_sta_id;
@@ -700,7 +700,7 @@ static int iwl_mvm_tx_tso(struct iwl_mvm *mvm, struct sk_buff *skb,
 	snap_ip_tcp = 8 + skb_transport_header(skb) - skb_network_header(skb) +
 		tcp_hdrlen(skb);
 
-	dbg_max_amsdu_len = ACCESS_ONCE(mvm->max_amsdu_len);
+	dbg_max_amsdu_len = READ_ONCE(mvm->max_amsdu_len);
 
 	if (!sta->max_amsdu_len ||
 	    !ieee80211_is_data_qos(hdr->frame_control) ||
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index a06b6612b658..f25ce3a1ea50 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -1247,7 +1247,7 @@ restart:
 	spin_lock(&rxq->lock);
 	/* uCode's read index (stored in shared DRAM) indicates the last Rx
 	 * buffer that the driver may process (last buffer filled by ucode). */
-	r = le16_to_cpu(ACCESS_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF;
+	r = le16_to_cpu(READ_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF;
 	i = rxq->read;
 
 	/* W/A 9000 device step A0 wrap-around bug */
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 2e3e013ec95a..9ad3f4fe5894 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -2076,12 +2076,12 @@ static int iwl_trans_pcie_wait_txq_empty(struct iwl_trans *trans, int txq_idx)
 
 	IWL_DEBUG_TX_QUEUES(trans, "Emptying queue %d...\n", txq_idx);
 	txq = trans_pcie->txq[txq_idx];
-	wr_ptr = ACCESS_ONCE(txq->write_ptr);
+	wr_ptr = READ_ONCE(txq->write_ptr);
 
-	while (txq->read_ptr != ACCESS_ONCE(txq->write_ptr) &&
+	while (txq->read_ptr != READ_ONCE(txq->write_ptr) &&
 	       !time_after(jiffies,
 			   now + msecs_to_jiffies(IWL_FLUSH_WAIT_MS))) {
-		u8 write_ptr = ACCESS_ONCE(txq->write_ptr);
+		u8 write_ptr = READ_ONCE(txq->write_ptr);
 
 		if (WARN_ONCE(wr_ptr != write_ptr,
 			      "WR pointer moved while flushing %d -> %d\n",
@@ -2553,7 +2553,7 @@ static u32 iwl_trans_pcie_dump_rbs(struct iwl_trans *trans,
 
 	spin_lock(&rxq->lock);
 
-	r = le16_to_cpu(ACCESS_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF;
+	r = le16_to_cpu(READ_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF;
 
 	for (i = rxq->read, j = 0;
 	     i != r && j < allocated_rb_nums;
@@ -2814,7 +2814,7 @@ static struct iwl_trans_dump_data
 		/* Dump RBs is supported only for pre-9000 devices (1 queue) */
 		struct iwl_rxq *rxq = &trans_pcie->rxq[0];
 		/* RBs */
-		num_rbs = le16_to_cpu(ACCESS_ONCE(rxq->rb_stts->closed_rb_num))
+		num_rbs = le16_to_cpu(READ_ONCE(rxq->rb_stts->closed_rb_num))
 				      & 0x0FFF;
 		num_rbs = (num_rbs - rxq->read) & RX_QUEUE_MASK;
 		len += num_rbs * (sizeof(*data) +
diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 6467ffac9811..d2b3d6177a55 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -1380,7 +1380,7 @@ static void mac80211_hwsim_tx(struct ieee80211_hw *hw,
 	mac80211_hwsim_monitor_rx(hw, skb, channel);
 
 	/* wmediumd mode check */
-	_portid = ACCESS_ONCE(data->wmediumd);
+	_portid = READ_ONCE(data->wmediumd);
 
 	if (_portid)
 		return mac80211_hwsim_tx_frame_nl(hw, skb, _portid);
@@ -1477,7 +1477,7 @@ static void mac80211_hwsim_tx_frame(struct ieee80211_hw *hw,
 				    struct ieee80211_channel *chan)
 {
 	struct mac80211_hwsim_data *data = hw->priv;
-	u32 _pid = ACCESS_ONCE(data->wmediumd);
+	u32 _pid = READ_ONCE(data->wmediumd);
 
 	if (ieee80211_hw_check(hw, SUPPORTS_RC_TABLE)) {
 		struct ieee80211_tx_info *txi = IEEE80211_SKB_CB(skb);