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From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	"Sebastian A. Siewior" <bigeasy@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Ahmed S. Darwish" <a.darwish@linutronix.de>,
	Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org
Subject: [PATCH v2 2/6] net: phy: fixed_phy: Remove unused seqcount
Date: Wed,  3 Jun 2020 16:49:45 +0200
Message-ID: <20200603144949.1122421-3-a.darwish@linutronix.de> (raw)
In-Reply-To: <20200603144949.1122421-1-a.darwish@linutronix.de>

Commit bf7afb29d545 ("phy: improve safety of fixed-phy MII register
reading") protected the fixed PHY status with a sequence counter.

Two years later, commit d2b977939b18 ("net: phy: fixed-phy: remove
fixed_phy_update_state()") removed the sequence counter's write side
critical section -- neutralizing its read side retry loop.

Remove the unused seqcount.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/net/phy/fixed_phy.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c
index 4a3d34f40cb9..c4641b1704d6 100644
--- a/drivers/net/phy/fixed_phy.c
+++ b/drivers/net/phy/fixed_phy.c
@@ -19,7 +19,6 @@
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/gpio/consumer.h>
-#include <linux/seqlock.h>
 #include <linux/idr.h>
 #include <linux/netdevice.h>
 #include <linux/linkmode.h>
@@ -34,7 +33,6 @@ struct fixed_mdio_bus {
 struct fixed_phy {
 	int addr;
 	struct phy_device *phydev;
-	seqcount_t seqcount;
 	struct fixed_phy_status status;
 	bool no_carrier;
 	int (*link_update)(struct net_device *, struct fixed_phy_status *);
@@ -80,19 +78,17 @@ static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
 	list_for_each_entry(fp, &fmb->phys, node) {
 		if (fp->addr == phy_addr) {
 			struct fixed_phy_status state;
-			int s;
 
-			do {
-				s = read_seqcount_begin(&fp->seqcount);
-				fp->status.link = !fp->no_carrier;
-				/* Issue callback if user registered it. */
-				if (fp->link_update)
-					fp->link_update(fp->phydev->attached_dev,
-							&fp->status);
-				/* Check the GPIO for change in status */
-				fixed_phy_update(fp);
-				state = fp->status;
-			} while (read_seqcount_retry(&fp->seqcount, s));
+			fp->status.link = !fp->no_carrier;
+
+			/* Issue callback if user registered it. */
+			if (fp->link_update)
+				fp->link_update(fp->phydev->attached_dev,
+						&fp->status);
+
+			/* Check the GPIO for change in status */
+			fixed_phy_update(fp);
+			state = fp->status;
 
 			return swphy_read_reg(reg_num, &state);
 		}
@@ -150,8 +146,6 @@ static int fixed_phy_add_gpiod(unsigned int irq, int phy_addr,
 	if (!fp)
 		return -ENOMEM;
 
-	seqcount_init(&fp->seqcount);
-
 	if (irq != PHY_POLL)
 		fmb->mii_bus->irq[phy_addr] = irq;
 
-- 
2.20.1


  parent reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-03 14:49 [PATCH v2 0/6] seqlock: seqcount_t call sites bugfixes Ahmed S. Darwish
2020-06-03 14:49 ` [PATCH v2 1/6] net: core: device_rename: Use rwsem instead of a seqcount Ahmed S. Darwish
2020-06-03 14:49 ` Ahmed S. Darwish [this message]
2020-06-03 16:19   ` [PATCH v2 2/6] net: phy: fixed_phy: Remove unused seqcount Andrew Lunn
2020-06-03 14:49 ` [PATCH v2 3/6] u64_stats: Document writer non-preemptibility requirement Ahmed S. Darwish
2020-06-03 14:49 ` [PATCH v2 4/6] net: mdiobus: Disable preemption upon u64_stats update Ahmed S. Darwish
2020-06-03 14:49 ` [PATCH v2 5/6] block: nr_sects_write(): Disable preemption on seqcount write Ahmed S. Darwish
2020-06-05  3:22   ` Jens Axboe
2020-06-03 14:49 ` [PATCH v2 6/6] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-06-04  8:49   ` Daniel Vetter
2020-06-04  7:28 ` [PATCH v2 0/6] seqlock: seqcount_t call sites bugfixes Daniel Vetter
2020-06-04  8:41   ` Ahmed S. Darwish
2020-06-04 22:50 ` David Miller

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