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, 20 insertions, 13 deletions

diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c
index 6651d9364e8f..6d0959b5158e 100644
--- a/drivers/net/sfc/rx.c
+++ b/drivers/net/sfc/rx.c
@@ -133,7 +133,7 @@ static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue)
         unsigned index, count;
 
         for (count = 0; count < EFX_RX_BATCH; ++count) {
-                index = rx_queue->added_count & EFX_RXQ_MASK;
+                index = rx_queue->added_count & rx_queue->ptr_mask;
                 rx_buf = efx_rx_buffer(rx_queue, index);
 
                 rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
@@ -208,7 +208,7 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
                 dma_addr += sizeof(struct efx_rx_page_state);
 
         split:
-                index = rx_queue->added_count & EFX_RXQ_MASK;
+                index = rx_queue->added_count & rx_queue->ptr_mask;
                 rx_buf = efx_rx_buffer(rx_queue, index);
                 rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;
                 rx_buf->skb = NULL;
@@ -285,7 +285,7 @@ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue,
          * we'd like to insert an additional descriptor whilst leaving
          * EFX_RXD_HEAD_ROOM for the non-recycle path */
         fill_level = (rx_queue->added_count - rx_queue->removed_count + 2);
-        if (unlikely(fill_level >= EFX_RXQ_SIZE - EFX_RXD_HEAD_ROOM)) {
+        if (unlikely(fill_level > rx_queue->max_fill)) {
                 /* We could place "state" on a list, and drain the list in
                  * efx_fast_push_rx_descriptors(). For now, this will do. */
                 return;
@@ -294,7 +294,7 @@ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue,
         ++state->refcnt;
         get_page(rx_buf->page);
 
-        index = rx_queue->added_count & EFX_RXQ_MASK;
+        index = rx_queue->added_count & rx_queue->ptr_mask;
         new_buf = efx_rx_buffer(rx_queue, index);
         new_buf->dma_addr = rx_buf->dma_addr ^ (PAGE_SIZE >> 1);
         new_buf->skb = NULL;
@@ -319,7 +319,7 @@ static void efx_recycle_rx_buffer(struct efx_channel *channel,
             page_count(rx_buf->page) == 1)
                 efx_resurrect_rx_buffer(rx_queue, rx_buf);
 
-        index = rx_queue->added_count & EFX_RXQ_MASK;
+        index = rx_queue->added_count & rx_queue->ptr_mask;
         new_buf = efx_rx_buffer(rx_queue, index);
 
         memcpy(new_buf, rx_buf, sizeof(*new_buf));
@@ -347,7 +347,7 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
 
         /* Calculate current fill level, and exit if we don't need to fill */
         fill_level = (rx_queue->added_count - rx_queue->removed_count);
-        EFX_BUG_ON_PARANOID(fill_level > EFX_RXQ_SIZE);
+        EFX_BUG_ON_PARANOID(fill_level > rx_queue->efx->rxq_entries);
         if (fill_level >= rx_queue->fast_fill_trigger)
                 goto out;
 
@@ -650,15 +650,22 @@ void efx_rx_strategy(struct efx_channel *channel)
 int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
 {
         struct efx_nic *efx = rx_queue->efx;
-        unsigned int rxq_size;
+        unsigned int entries;
         int rc;
 
+        /* Create the smallest power-of-two aligned ring */
+        entries = max(roundup_pow_of_two(efx->rxq_entries), EFX_MIN_DMAQ_SIZE);
+        EFX_BUG_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE);
+        rx_queue->ptr_mask = entries - 1;
+
         netif_dbg(efx, probe, efx->net_dev,
-                  "creating RX queue %d\n", efx_rx_queue_index(rx_queue));
+                  "creating RX queue %d size %#x mask %#x\n",
+                  efx_rx_queue_index(rx_queue), efx->rxq_entries,
+                  rx_queue->ptr_mask);
 
         /* Allocate RX buffers */
-        rxq_size = EFX_RXQ_SIZE * sizeof(*rx_queue->buffer);
-        rx_queue->buffer = kzalloc(rxq_size, GFP_KERNEL);
+        rx_queue->buffer = kzalloc(entries * sizeof(*rx_queue->buffer),
+                                   GFP_KERNEL);
         if (!rx_queue->buffer)
                 return -ENOMEM;
 
@@ -672,6 +679,7 @@ int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
 
 void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
 {
+        struct efx_nic *efx = rx_queue->efx;
         unsigned int max_fill, trigger, limit;
 
         netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
@@ -682,10 +690,9 @@ void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
         rx_queue->notified_count = 0;
         rx_queue->removed_count = 0;
         rx_queue->min_fill = -1U;
-        rx_queue->min_overfill = -1U;
 
         /* Initialise limit fields */
-        max_fill = EFX_RXQ_SIZE - EFX_RXD_HEAD_ROOM;
+        max_fill = efx->rxq_entries - EFX_RXD_HEAD_ROOM;
         trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
         limit = max_fill * min(rx_refill_limit, 100U) / 100U;
 
@@ -710,7 +717,7 @@ void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
 
         /* Release RX buffers NB start at index 0 not current HW ptr */
         if (rx_queue->buffer) {
-                for (i = 0; i <= EFX_RXQ_MASK; i++) {
+                for (i = 0; i <= rx_queue->ptr_mask; i++) {
                         rx_buf = efx_rx_buffer(rx_queue, i);
                         efx_fini_rx_buffer(rx_queue, rx_buf);
                 }