ath9k-devel.lists.ath9k.org archive mirror
 help / color / mirror / Atom feed
From: Mark Rutland <mark.rutland@arm.com>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] [PATCH 1/2] ath9k: ar9002_mac: kill off ACCESS_ONCE()
Date: Tue, 27 Dec 2016 18:49:58 +0000	[thread overview]
Message-ID: <1482864599-19995-2-git-send-email-mark.rutland@arm.com> (raw)
In-Reply-To: <1482864599-19995-1-git-send-email-mark.rutland@arm.com>

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 currently harmful.

However, for some new features (e.g. KTSAN / Kernel Thread Sanitizer),
it is necessary to instrument reads and writes separately, which is not
possible with ACCESS_ONCE(). This distinction is critical to correct
operation.

It's possible to transform the bulk of kernel code using the Coccinelle
script below. However, for some files (including the ath9k ar9002 mac
driver), this mangles the formatting. As a preparatory step, this patch
converts the driver to use {READ,WRITE}_ONCE() without said mangling.

----
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>
Cc: ath9k-devel at qca.qualcomm.com
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless at vger.kernel.org
Cc: ath9k-devel at lists.ath9k.org
Cc: netdev at vger.kernel.org
---
 drivers/net/wireless/ath/ath9k/ar9002_mac.c | 64 ++++++++++++++---------------
 1 file changed, 32 insertions(+), 32 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ar9002_mac.c b/drivers/net/wireless/ath/ath9k/ar9002_mac.c
index f816909..4b3c9b1 100644
--- a/drivers/net/wireless/ath/ath9k/ar9002_mac.c
+++ b/drivers/net/wireless/ath/ath9k/ar9002_mac.c
@@ -220,8 +220,8 @@ ar9002_set_txdesc(struct ath_hw *ah, void *ds, struct ath_tx_info *i)
 	ads->ds_txstatus6 = ads->ds_txstatus7 = 0;
 	ads->ds_txstatus8 = ads->ds_txstatus9 = 0;
 
-	ACCESS_ONCE(ads->ds_link) = i->link;
-	ACCESS_ONCE(ads->ds_data) = i->buf_addr[0];
+	WRITE_ONCE(ads->ds_link, i->link);
+	WRITE_ONCE(ads->ds_data, i->buf_addr[0]);
 
 	ctl1 = i->buf_len[0] | (i->is_last ? 0 : AR_TxMore);
 	ctl6 = SM(i->keytype, AR_EncrType);
@@ -235,26 +235,26 @@ ar9002_set_txdesc(struct ath_hw *ah, void *ds, struct ath_tx_info *i)
 
 	if ((i->is_first || i->is_last) &&
 	    i->aggr != AGGR_BUF_MIDDLE && i->aggr != AGGR_BUF_LAST) {
-		ACCESS_ONCE(ads->ds_ctl2) = set11nTries(i->rates, 0)
+		WRITE_ONCE(ads->ds_ctl2, set11nTries(i->rates, 0)
 			| set11nTries(i->rates, 1)
 			| set11nTries(i->rates, 2)
 			| set11nTries(i->rates, 3)
 			| (i->dur_update ? AR_DurUpdateEna : 0)
-			| SM(0, AR_BurstDur);
+			| SM(0, AR_BurstDur));
 
-		ACCESS_ONCE(ads->ds_ctl3) = set11nRate(i->rates, 0)
+		WRITE_ONCE(ads->ds_ctl3, set11nRate(i->rates, 0)
 			| set11nRate(i->rates, 1)
 			| set11nRate(i->rates, 2)
-			| set11nRate(i->rates, 3);
+			| set11nRate(i->rates, 3));
 	} else {
-		ACCESS_ONCE(ads->ds_ctl2) = 0;
-		ACCESS_ONCE(ads->ds_ctl3) = 0;
+		WRITE_ONCE(ads->ds_ctl2, 0);
+		WRITE_ONCE(ads->ds_ctl3, 0);
 	}
 
 	if (!i->is_first) {
-		ACCESS_ONCE(ads->ds_ctl0) = 0;
-		ACCESS_ONCE(ads->ds_ctl1) = ctl1;
-		ACCESS_ONCE(ads->ds_ctl6) = ctl6;
+		WRITE_ONCE(ads->ds_ctl0, 0);
+		WRITE_ONCE(ads->ds_ctl1, ctl1);
+		WRITE_ONCE(ads->ds_ctl6, ctl6);
 		return;
 	}
 
@@ -279,7 +279,7 @@ ar9002_set_txdesc(struct ath_hw *ah, void *ds, struct ath_tx_info *i)
 		break;
 	}
 
-	ACCESS_ONCE(ads->ds_ctl0) = (i->pkt_len & AR_FrameLen)
+	WRITE_ONCE(ads->ds_ctl0, (i->pkt_len & AR_FrameLen)
 		| (i->flags & ATH9K_TXDESC_VMF ? AR_VirtMoreFrag : 0)
 		| SM(i->txpower[0], AR_XmitPower0)
 		| (i->flags & ATH9K_TXDESC_VEOL ? AR_VEOL : 0)
@@ -287,29 +287,29 @@ ar9002_set_txdesc(struct ath_hw *ah, void *ds, struct ath_tx_info *i)
 		| (i->keyix != ATH9K_TXKEYIX_INVALID ? AR_DestIdxValid : 0)
 		| (i->flags & ATH9K_TXDESC_CLRDMASK ? AR_ClrDestMask : 0)
 		| (i->flags & ATH9K_TXDESC_RTSENA ? AR_RTSEnable :
-		   (i->flags & ATH9K_TXDESC_CTSENA ? AR_CTSEnable : 0));
+		   (i->flags & ATH9K_TXDESC_CTSENA ? AR_CTSEnable : 0)));
 
-	ACCESS_ONCE(ads->ds_ctl1) = ctl1;
-	ACCESS_ONCE(ads->ds_ctl6) = ctl6;
+	WRITE_ONCE(ads->ds_ctl1, ctl1);
+	WRITE_ONCE(ads->ds_ctl6, ctl6);
 
 	if (i->aggr == AGGR_BUF_MIDDLE || i->aggr == AGGR_BUF_LAST)
 		return;
 
-	ACCESS_ONCE(ads->ds_ctl4) = set11nPktDurRTSCTS(i->rates, 0)
-		| set11nPktDurRTSCTS(i->rates, 1);
+	WRITE_ONCE(ads->ds_ctl4, set11nPktDurRTSCTS(i->rates, 0)
+		| set11nPktDurRTSCTS(i->rates, 1));
 
-	ACCESS_ONCE(ads->ds_ctl5) = set11nPktDurRTSCTS(i->rates, 2)
-		| set11nPktDurRTSCTS(i->rates, 3);
+	WRITE_ONCE(ads->ds_ctl5, set11nPktDurRTSCTS(i->rates, 2)
+		| set11nPktDurRTSCTS(i->rates, 3));
 
-	ACCESS_ONCE(ads->ds_ctl7) = set11nRateFlags(i->rates, 0)
+	WRITE_ONCE(ads->ds_ctl7, set11nRateFlags(i->rates, 0)
 		| set11nRateFlags(i->rates, 1)
 		| set11nRateFlags(i->rates, 2)
 		| set11nRateFlags(i->rates, 3)
-		| SM(i->rtscts_rate, AR_RTSCTSRate);
+		| SM(i->rtscts_rate, AR_RTSCTSRate));
 
-	ACCESS_ONCE(ads->ds_ctl9) = SM(i->txpower[1], AR_XmitPower1);
-	ACCESS_ONCE(ads->ds_ctl10) = SM(i->txpower[2], AR_XmitPower2);
-	ACCESS_ONCE(ads->ds_ctl11) = SM(i->txpower[3], AR_XmitPower3);
+	WRITE_ONCE(ads->ds_ctl9, SM(i->txpower[1], AR_XmitPower1));
+	WRITE_ONCE(ads->ds_ctl10, SM(i->txpower[2], AR_XmitPower2));
+	WRITE_ONCE(ads->ds_ctl11, SM(i->txpower[3], AR_XmitPower3));
 }
 
 static int ar9002_hw_proc_txdesc(struct ath_hw *ah, void *ds,
@@ -318,7 +318,7 @@ static int ar9002_hw_proc_txdesc(struct ath_hw *ah, void *ds,
 	struct ar5416_desc *ads = AR5416DESC(ds);
 	u32 status;
 
-	status = ACCESS_ONCE(ads->ds_txstatus9);
+	status = READ_ONCE(ads->ds_txstatus9);
 	if ((status & AR_TxDone) == 0)
 		return -EINPROGRESS;
 
@@ -332,7 +332,7 @@ static int ar9002_hw_proc_txdesc(struct ath_hw *ah, void *ds,
 	ts->ts_rateindex = MS(status, AR_FinalTxIdx);
 	ts->ts_seqnum = MS(status, AR_SeqNum);
 
-	status = ACCESS_ONCE(ads->ds_txstatus0);
+	status = READ_ONCE(ads->ds_txstatus0);
 	ts->ts_rssi_ctl0 = MS(status, AR_TxRSSIAnt00);
 	ts->ts_rssi_ctl1 = MS(status, AR_TxRSSIAnt01);
 	ts->ts_rssi_ctl2 = MS(status, AR_TxRSSIAnt02);
@@ -342,7 +342,7 @@ static int ar9002_hw_proc_txdesc(struct ath_hw *ah, void *ds,
 		ts->ba_high = ads->AR_BaBitmapHigh;
 	}
 
-	status = ACCESS_ONCE(ads->ds_txstatus1);
+	status = READ_ONCE(ads->ds_txstatus1);
 	if (status & AR_FrmXmitOK)
 		ts->ts_status |= ATH9K_TX_ACKED;
 	else {
@@ -371,7 +371,7 @@ static int ar9002_hw_proc_txdesc(struct ath_hw *ah, void *ds,
 	ts->ts_longretry = MS(status, AR_DataFailCnt);
 	ts->ts_virtcol = MS(status, AR_VirtRetryCnt);
 
-	status = ACCESS_ONCE(ads->ds_txstatus5);
+	status = READ_ONCE(ads->ds_txstatus5);
 	ts->ts_rssi = MS(status, AR_TxRSSICombined);
 	ts->ts_rssi_ext0 = MS(status, AR_TxRSSIAnt10);
 	ts->ts_rssi_ext1 = MS(status, AR_TxRSSIAnt11);
@@ -390,13 +390,13 @@ static int ar9002_hw_get_duration(struct ath_hw *ah, const void *ds, int index)
 
 	switch (index) {
 	case 0:
-		return MS(ACCESS_ONCE(ads->ds_ctl4), AR_PacketDur0);
+		return MS(READ_ONCE(ads->ds_ctl4), AR_PacketDur0);
 	case 1:
-		return MS(ACCESS_ONCE(ads->ds_ctl4), AR_PacketDur1);
+		return MS(READ_ONCE(ads->ds_ctl4), AR_PacketDur1);
 	case 2:
-		return MS(ACCESS_ONCE(ads->ds_ctl5), AR_PacketDur2);
+		return MS(READ_ONCE(ads->ds_ctl5), AR_PacketDur2);
 	case 3:
-		return MS(ACCESS_ONCE(ads->ds_ctl5), AR_PacketDur3);
+		return MS(READ_ONCE(ads->ds_ctl5), AR_PacketDur3);
 	default:
 		return -1;
 	}
-- 
2.7.4

  reply	other threads:[~2016-12-27 18:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-27 18:49 [ath9k-devel] [PATCH 0/2] ath9k: kill of ACCESS_ONCE() in MAC drivers Mark Rutland
2016-12-27 18:49 ` Mark Rutland [this message]
2017-01-12 11:00   ` [ath9k-devel] [1/2] ath9k: ar9002_mac: kill off ACCESS_ONCE() Kalle Valo
2016-12-27 18:49 ` [ath9k-devel] [PATCH 2/2] ath9k: ar9003_mac: " Mark Rutland

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1482864599-19995-2-git-send-email-mark.rutland@arm.com \
    --to=mark.rutland@arm.com \
    --cc=ath9k-devel@lists.ath9k.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).