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

[Sebastian Andrzej Siewior]

From: Anna-Maria Gleixner <anna-ma...@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 <klass...@mathematik.tu-chemnitz.de>
Signed-off-by: Anna-Maria Gleixner <anna-ma...@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bige...@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