Re: [PATCH v2 RFC net-next 09/18] net: mvpp2: add FCA RXQ non occupied descriptor threshold
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Date: 2021-01-24 13:02:43
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On Sun, Jan 24, 2021 at 01:43:58PM +0200, stefanc@marvell.com wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c index 9d69752..0f5069f 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c@@ -1154,6 +1154,9 @@ static void mvpp2_interrupts_mask(void *arg) mvpp2_thread_write(port->priv, mvpp2_cpu_to_thread(port->priv, smp_processor_id()), MVPP2_ISR_RX_TX_MASK_REG(port->id), 0); + mvpp2_thread_write(port->priv, + mvpp2_cpu_to_thread(port->priv, smp_processor_id()), + MVPP2_ISR_RX_ERR_CAUSE_REG(port->id), 0);
I wonder if this should be refactored:
u32 thread = mvpp2_cpu_to_thread(port->priv, smp_processor_id());
mvpp2_thread_write(port->priv, thread,
MVPP2_ISR_RX_TX_MASK_REG(port->id), 0);
mvpp2_thread_write(port->priv, thread,
MVPP2_ISR_RX_ERR_CAUSE_REG(port->id), 0);
to avoid having to recompute mvpp2_cpu_to_thread() for each write?
However, looking deeper...
static void mvpp2_interrupts_mask(void *arg)
{
struct mvpp2_port *port = arg;
u32 thread;
int cpu;
cpu = smp_processor_id();
if (cpu > port->priv->nthreads)
return
thread = mvpp2_cpu_to_thread(port->priv, cpu);
...
and I wonder about that condition - "cpu > port->priv->nthreads". If
cpu == port->priv->nthreads, then mvpp2_cpu_to_thread() will return
zero, just like the cpu=0 case. This leads me to suspect that this
comparison off by one.
--
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