Discussion:
[PATCHv5 3/4] sparc64: Avoid irqsave/restore on vio.lock if in_softirq()
(too old to reply)
Sowmini Varadhan
2014-10-22 22:12:45 UTC
Permalink
For NAPIfied drivers , there is no need to
synchronize by doing irqsave/restore on vio.lock in the I/O
path.

Signed-off-by: Sowmini Varadhan <***@oracle.com>
---
arch/sparc/kernel/viohs.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/sparc/kernel/viohs.c b/arch/sparc/kernel/viohs.c
index 526fcb5..92e2a32 100644
--- a/arch/sparc/kernel/viohs.c
+++ b/arch/sparc/kernel/viohs.c
@@ -747,10 +747,11 @@ EXPORT_SYMBOL(vio_ldc_free);

void vio_port_up(struct vio_driver_state *vio)
{
- unsigned long flags;
+ unsigned long flags = 0;
int err, state;

- spin_lock_irqsave(&vio->lock, flags);
+ if (!in_softirq())
+ spin_lock_irqsave(&vio->lock, flags);

state = ldc_state(vio->lp);

@@ -777,7 +778,8 @@ void vio_port_up(struct vio_driver_state *vio)
mod_timer(&vio->timer, expires);
}

- spin_unlock_irqrestore(&vio->lock, flags);
+ if (!in_softirq())
+ spin_unlock_irqrestore(&vio->lock, flags);
}
EXPORT_SYMBOL(vio_port_up);
--
1.8.4.2

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