sfc: Make the dmaq size a run-time setting (rather than compile-time)

- Allow the ring size to be specified in non
   power-of-two sizes (for instance to limit
   the amount of receive buffers).
 - Automatically size the event queue.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 4b42e61e3c7d..6166e2207160 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -348,7 +348,7 @@ void efx_process_channel_now(struct efx_channel *channel)
         napi_disable(&channel->napi_str);
 
         /* Poll the channel */
-        efx_process_channel(channel, EFX_EVQ_SIZE);
+        efx_process_channel(channel, channel->eventq_mask + 1);
 
         /* Ack the eventq. This may cause an interrupt to be generated
          * when they are reenabled */
@@ -365,9 +365,18 @@ void efx_process_channel_now(struct efx_channel *channel)
  */
 static int efx_probe_eventq(struct efx_channel *channel)
 {
+        struct efx_nic *efx = channel->efx;
+        unsigned long entries;
+
         netif_dbg(channel->efx, probe, channel->efx->net_dev,
                   "chan %d create event queue\n", channel->channel);
 
+        /* Build an event queue with room for one event per tx and rx buffer,
+         * plus some extra for link state events and MCDI completions. */
+        entries = roundup_pow_of_two(efx->rxq_entries + efx->txq_entries + 128);
+        EFX_BUG_ON_PARANOID(entries > EFX_MAX_EVQ_SIZE);
+        channel->eventq_mask = max(entries, EFX_MIN_EVQ_SIZE) - 1;
+
         return efx_nic_probe_eventq(channel);
 }
 
@@ -1191,6 +1200,7 @@ static int efx_probe_all(struct efx_nic *efx)
         }
 
         /* Create channels */
+        efx->rxq_entries = efx->txq_entries = EFX_DEFAULT_DMAQ_SIZE;
         efx_for_each_channel(channel, efx) {
                 rc = efx_probe_channel(channel);
                 if (rc) {
@@ -2101,9 +2111,6 @@ static int efx_init_struct(struct efx_nic *efx, struct efx_nic_type *type,
 
         efx->type = type;
 
-        /* As close as we can get to guaranteeing that we don't overflow */
-        BUILD_BUG_ON(EFX_EVQ_SIZE < EFX_TXQ_SIZE + EFX_RXQ_SIZE);
-
         EFX_BUG_ON_PARANOID(efx->type->phys_addr_channels > EFX_MAX_CHANNELS);
 
         /* Higher numbered interrupt modes are less capable! */