3c59x patches and the removal of an unused function

3c59x patches and the removal of an unused function

[Sebastian Andrzej Siewior]

The first patch removes an unused function. The goal of remaining three
patches is to get rid of the local_irq_save() usage in the driver which
benefits -RT.

Sebastian

[PATCH 1/4] net: u64_stats_sync: Remove functions without user

[Sebastian Andrzej Siewior]

From: Anna-Maria Gleixner <anna-maria@linutronix.de>

Commit 67db3e4bfbc9 ("tcp: no longer hold ehash lock while calling
tcp_get_info()") removes the only users of u64_stats_update_end/begin_raw()
without removing the function in header file.

Remove no longer used functions.

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 include/linux/u64_stats_sync.h | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
index 07ee0f84a46c..a27604f99ed0 100644
--- a/include/linux/u64_stats_sync.h
+++ b/include/linux/u64_stats_sync.h
@@ -112,20 +112,6 @@ u64_stats_update_end_irqrestore(struct u64_stats_sync *syncp,
 #endif
 }
 
-static inline void u64_stats_update_begin_raw(struct u64_stats_sync *syncp)
-{
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-	raw_write_seqcount_begin(&syncp->seq);
-#endif
-}
-
-static inline void u64_stats_update_end_raw(struct u64_stats_sync *syncp)
-{
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-	raw_write_seqcount_end(&syncp->seq);
-#endif
-}
-
 static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *syncp)
 {
 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-- 
2.17.0

[PATCH 2/4] net: 3com: 3c59x: Move boomerang/vortex conditional into function

[Sebastian Andrzej Siewior]

From: Anna-Maria Gleixner <anna-maria@linutronix.de>

If vp->full_bus_master_tx is set, vp->full_bus_master_rx is set as well
(see vortex_probe1()). Therefore the conditionals for the decision if
boomerang or vortex ISR is executed have the same result. Instead of
repeating the explicit conditional execution of the boomerang/vortex ISR,
move it into an own function.

No functional change.

Cc: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/net/ethernet/3com/3c59x.c | 34 ++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/3com/3c59x.c b/drivers/net/ethernet/3com/3c59x.c
index 36c8950dbd2d..0cfdb07f3e59 100644
--- a/drivers/net/ethernet/3com/3c59x.c
+++ b/drivers/net/ethernet/3com/3c59x.c
@@ -765,8 +765,9 @@ static netdev_tx_t boomerang_start_xmit(struct sk_buff *skb,
 					struct net_device *dev);
 static int vortex_rx(struct net_device *dev);
 static int boomerang_rx(struct net_device *dev);
-static irqreturn_t vortex_interrupt(int irq, void *dev_id);
-static irqreturn_t boomerang_interrupt(int irq, void *dev_id);
+static irqreturn_t vortex_boomerang_interrupt(int irq, void *dev_id);
+static irqreturn_t _vortex_interrupt(int irq, struct net_device *dev);
+static irqreturn_t _boomerang_interrupt(int irq, struct net_device *dev);
 static int vortex_close(struct net_device *dev);
 static void dump_tx_ring(struct net_device *dev);
 static void update_stats(void __iomem *ioaddr, struct net_device *dev);
@@ -838,10 +839,9 @@ MODULE_PARM_DESC(use_mmio, "3c59x: use memory-mapped PCI I/O resource (0-1)");
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void poll_vortex(struct net_device *dev)
 {
-	struct vortex_private *vp = netdev_priv(dev);
 	unsigned long flags;
 	local_irq_save(flags);
-	(vp->full_bus_master_rx ? boomerang_interrupt:vortex_interrupt)(dev->irq,dev);
+	vortex_boomerang_interrupt(dev->irq, dev);
 	local_irq_restore(flags);
 }
 #endif
@@ -1729,8 +1729,7 @@ vortex_open(struct net_device *dev)
 	dma_addr_t dma;
 
 	/* Use the now-standard shared IRQ implementation. */
-	if ((retval = request_irq(dev->irq, vp->full_bus_master_rx ?
-				boomerang_interrupt : vortex_interrupt, IRQF_SHARED, dev->name, dev))) {
+	if ((retval = request_irq(dev->irq, vortex_boomerang_interrupt, IRQF_SHARED, dev->name, dev))) {
 		pr_err("%s: Could not reserve IRQ %d\n", dev->name, dev->irq);
 		goto err;
 	}
@@ -1911,10 +1910,7 @@ static void vortex_tx_timeout(struct net_device *dev)
 			 */
 			unsigned long flags;
 			local_irq_save(flags);
-			if (vp->full_bus_master_tx)
-				boomerang_interrupt(dev->irq, dev);
-			else
-				vortex_interrupt(dev->irq, dev);
+			vortex_boomerang_interrupt(dev->irq, dev);
 			local_irq_restore(flags);
 		}
 	}
@@ -2267,9 +2263,8 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev)
  */
 
 static irqreturn_t
-vortex_interrupt(int irq, void *dev_id)
+_vortex_interrupt(int irq, struct net_device *dev)
 {
-	struct net_device *dev = dev_id;
 	struct vortex_private *vp = netdev_priv(dev);
 	void __iomem *ioaddr;
 	int status;
@@ -2386,9 +2381,8 @@ vortex_interrupt(int irq, void *dev_id)
  */
 
 static irqreturn_t
-boomerang_interrupt(int irq, void *dev_id)
+_boomerang_interrupt(int irq, struct net_device *dev)
 {
-	struct net_device *dev = dev_id;
 	struct vortex_private *vp = netdev_priv(dev);
 	void __iomem *ioaddr;
 	int status;
@@ -2526,6 +2520,18 @@ boomerang_interrupt(int irq, void *dev_id)
 	return IRQ_RETVAL(handled);
 }
 
+static irqreturn_t
+vortex_boomerang_interrupt(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct vortex_private *vp = netdev_priv(dev);
+
+	if (vp->full_bus_master_rx)
+		return _boomerang_interrupt(dev->irq, dev);
+	else
+		return _vortex_interrupt(dev->irq, dev);
+}
+
 static int vortex_rx(struct net_device *dev)
 {
 	struct vortex_private *vp = netdev_priv(dev);
-- 
2.17.0

[PATCH 3/4] net: 3com: 3c59x: Pull locking out of ISR

[Sebastian Andrzej Siewior]

From: Anna-Maria Gleixner <anna-maria@linutronix.de>

Locking is done in the same way in _vortex_interrupt() and
_boomerang_interrupt(). To prevent duplication, move the locking into the
calling vortex_boomerang_interrupt() function.

No functional change.

Cc: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/net/ethernet/3com/3c59x.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/3com/3c59x.c b/drivers/net/ethernet/3com/3c59x.c
index 0cfdb07f3e59..fdafe25da153 100644
--- a/drivers/net/ethernet/3com/3c59x.c
+++ b/drivers/net/ethernet/3com/3c59x.c
@@ -2273,7 +2273,6 @@ _vortex_interrupt(int irq, struct net_device *dev)
 	unsigned int bytes_compl = 0, pkts_compl = 0;
 
 	ioaddr = vp->ioaddr;
-	spin_lock(&vp->lock);
 
 	status = ioread16(ioaddr + EL3_STATUS);
 
@@ -2371,7 +2370,6 @@ _vortex_interrupt(int irq, struct net_device *dev)
 		pr_debug("%s: exiting interrupt, status %4.4x.\n",
 			   dev->name, status);
 handler_exit:
-	spin_unlock(&vp->lock);
 	return IRQ_RETVAL(handled);
 }
 
@@ -2392,12 +2390,6 @@ _boomerang_interrupt(int irq, struct net_device *dev)
 
 	ioaddr = vp->ioaddr;
 
-
-	/*
-	 * It seems dopey to put the spinlock this early, but we could race against vortex_tx_timeout
-	 * and boomerang_start_xmit
-	 */
-	spin_lock(&vp->lock);
 	vp->handling_irq = 1;
 
 	status = ioread16(ioaddr + EL3_STATUS);
@@ -2516,7 +2508,6 @@ _boomerang_interrupt(int irq, struct net_device *dev)
 			   dev->name, status);
 handler_exit:
 	vp->handling_irq = 0;
-	spin_unlock(&vp->lock);
 	return IRQ_RETVAL(handled);
 }
 
@@ -2525,11 +2516,18 @@ vortex_boomerang_interrupt(int irq, void *dev_id)
 {
 	struct net_device *dev = dev_id;
 	struct vortex_private *vp = netdev_priv(dev);
+	irqreturn_t ret;
+
+	spin_lock(&vp->lock);
 
 	if (vp->full_bus_master_rx)
-		return _boomerang_interrupt(dev->irq, dev);
+		ret = _boomerang_interrupt(dev->irq, dev);
 	else
-		return _vortex_interrupt(dev->irq, dev);
+		ret = _vortex_interrupt(dev->irq, dev);
+
+	spin_unlock(&vp->lock);
+
+	return ret;
 }
 
 static int vortex_rx(struct net_device *dev)
-- 
2.17.0

[PATCH 4/4] net: 3com: 3c59x: irq save variant of ISR

[Sebastian Andrzej Siewior]

From: Anna-Maria Gleixner <anna-maria@linutronix.de>

When vortex_boomerang_interrupt() is invoked from vortex_tx_timeout() or
poll_vortex() interrupts must be disabled. This detaches the interrupt
disable logic from locking which requires patching for PREEMPT_RT.

The advantage of avoiding spin_lock_irqsave() in the interrupt handler is
minimal, but converting it removes all the extra code for callers which
come not from interrupt context.

Cc: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/net/ethernet/3com/3c59x.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/3com/3c59x.c b/drivers/net/ethernet/3com/3c59x.c
index fdafe25da153..cabbe227bb98 100644
--- a/drivers/net/ethernet/3com/3c59x.c
+++ b/drivers/net/ethernet/3com/3c59x.c
@@ -839,10 +839,7 @@ MODULE_PARM_DESC(use_mmio, "3c59x: use memory-mapped PCI I/O resource (0-1)");
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void poll_vortex(struct net_device *dev)
 {
-	unsigned long flags;
-	local_irq_save(flags);
 	vortex_boomerang_interrupt(dev->irq, dev);
-	local_irq_restore(flags);
 }
 #endif
 
@@ -1904,15 +1901,7 @@ static void vortex_tx_timeout(struct net_device *dev)
 		pr_err("%s: Interrupt posted but not delivered --"
 			   " IRQ blocked by another device?\n", dev->name);
 		/* Bad idea here.. but we might as well handle a few events. */
-		{
-			/*
-			 * Block interrupts because vortex_interrupt does a bare spin_lock()
-			 */
-			unsigned long flags;
-			local_irq_save(flags);
-			vortex_boomerang_interrupt(dev->irq, dev);
-			local_irq_restore(flags);
-		}
+		vortex_boomerang_interrupt(dev->irq, dev);
 	}
 
 	if (vortex_debug > 0)
@@ -2516,16 +2505,17 @@ vortex_boomerang_interrupt(int irq, void *dev_id)
 {
 	struct net_device *dev = dev_id;
 	struct vortex_private *vp = netdev_priv(dev);
+	unsigned long flags;
 	irqreturn_t ret;
 
-	spin_lock(&vp->lock);
+	spin_lock_irqsave(&vp->lock, flags);
 
 	if (vp->full_bus_master_rx)
 		ret = _boomerang_interrupt(dev->irq, dev);
 	else
 		ret = _vortex_interrupt(dev->irq, dev);
 
-	spin_unlock(&vp->lock);
+	spin_unlock_irqrestore(&vp->lock, flags);
 
 	return ret;
 }
-- 
2.17.0

Re: [PATCH 2/4] net: 3com: 3c59x: Move boomerang/vortex conditional into function

[Sebastian Andrzej Siewior]

On 2018-05-04 17:17:47 [+0200], To netdev@vger.kernel.org wrote:
> From: Anna-Maria Gleixner <anna-maria@linutronix.de>
> 
> If vp->full_bus_master_tx is set, vp->full_bus_master_rx is set as well
> (see vortex_probe1()). Therefore the conditionals for the decision if
> boomerang or vortex ISR is executed have the same result. Instead of
> repeating the explicit conditional execution of the boomerang/vortex ISR,
> move it into an own function.
> 
> No functional change.
> 
> Cc: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>

Steffen, this email address is still listed in the MAINTAINERS file for
the driver and rejects emails.

Sebastian

Re: [PATCH 2/4] net: 3com: 3c59x: Move boomerang/vortex conditional into function

[Steffen Klassert]

On Fri, May 04, 2018 at 05:22:28PM +0200, Sebastian Andrzej Siewior wrote:
> On 2018-05-04 17:17:47 [+0200], To netdev@vger.kernel.org wrote:
> > From: Anna-Maria Gleixner <anna-maria@linutronix.de>
> > 
> > If vp->full_bus_master_tx is set, vp->full_bus_master_rx is set as well
> > (see vortex_probe1()). Therefore the conditionals for the decision if
> > boomerang or vortex ISR is executed have the same result. Instead of
> > repeating the explicit conditional execution of the boomerang/vortex ISR,
> > move it into an own function.
> > 
> > No functional change.
> > 
> > Cc: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>
> 
> Steffen, this email address is still listed in the MAINTAINERS file for
> the driver and rejects emails.

Thanks for the hint, I'll update the address.

Re: 3c59x patches and the removal of an unused function

[David Miller]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri,  4 May 2018 17:17:45 +0200

> The first patch removes an unused function. The goal of remaining three
> patches is to get rid of the local_irq_save() usage in the driver which
> benefits -RT.

Series applied, thanks.