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Commit 5b9e207c authored by Ben Hutchings's avatar Ben Hutchings Committed by Jeff Garzik
Browse files

sfc: Correct and expand some comments 



These comments have been revised in response to questions raised by Andrew
Morton in <20080501120858.207b6dd6.akpm@linux-foundation.org>.

Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 086ea356

drivers/net/sfc/efx.c

+14 −6
Original line number Diff line number Diff line
@@ -199,11 +199,12 @@ static inline int efx_process_channel(struct efx_channel *channel, int rx_quota) 
 */

static inline void efx_channel_processed(struct efx_channel *channel)

{

	/* Write to EVQ_RPTR_REG.  If a new event arrived in a race

	 * with finishing processing, a new interrupt will be raised.

	 */

	/* The interrupt handler for this channel may set work_pending

	 * as soon as we acknowledge the events we've seen.  Make sure

	 * it's cleared before then. */

	channel->work_pending = 0;

	smp_wmb(); /* Ensure channel updated before any new interrupt. */

	smp_wmb();



	falcon_eventq_read_ack(channel);

}
@@ -427,9 +428,12 @@ static void efx_start_channel(struct efx_channel *channel) 
		netif_napi_add(channel->napi_dev, &channel->napi_str,

			       efx_poll, napi_weight);



	/* The interrupt handler for this channel may set work_pending

	 * as soon as we enable it.  Make sure it's cleared before

	 * then.  Similarly, make sure it sees the enabled flag set. */

	channel->work_pending = 0;

	channel->enabled = 1;

	smp_wmb(); /* ensure channel updated before first interrupt */

	smp_wmb();



	napi_enable(&channel->napi_str);
@@ -1332,13 +1336,17 @@ static int efx_net_stop(struct net_device *net_dev) 
	return 0;

}



/* Context: process, dev_base_lock held, non-blocking. */

/* Context: process, dev_base_lock or RTNL held, non-blocking. */

static struct net_device_stats *efx_net_stats(struct net_device *net_dev)

{

	struct efx_nic *efx = net_dev->priv;

	struct efx_mac_stats *mac_stats = &efx->mac_stats;

	struct net_device_stats *stats = &net_dev->stats;



	/* Update stats if possible, but do not wait if another thread

	 * is updating them (or resetting the NIC); slightly stale

	 * stats are acceptable.

	 */

	if (!spin_trylock(&efx->stats_lock))

		return stats;

	if (efx->state == STATE_RUNNING) {