bnx2x: avoid atomic allocations during initialization

During initialization bnx2x allocates significant amounts of memory
(for rx data, rx SGEs, TPA pool) using atomic allocations.

I received a report where bnx2x failed to allocate SGEs and it had
to fall back to TPA-less operation.

Let's use GFP_KERNEL allocations during initialization, which runs
in process context. Add gfp_t parameters to functions that are used
both in initialization and in the receive path.

Use an unlikely branch in bnx2x_frag_alloc() to avoid atomic allocation
by netdev_alloc_frag(). The branch is taken several thousands of times
during initialization, but then never more. Note that fp->rx_frag_size
is never greater than PAGE_SIZE, so __get_free_page() can be used here.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 15 deletions

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 2361bf236ce3..90045c920d09 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -490,10 +490,10 @@ static void bnx2x_set_gro_params(struct sk_buff *skb, u16 parsing_flags,
         NAPI_GRO_CB(skb)->count = num_of_coalesced_segs;
 }
 
-static int bnx2x_alloc_rx_sge(struct bnx2x *bp,
-                              struct bnx2x_fastpath *fp, u16 index)
+static int bnx2x_alloc_rx_sge(struct bnx2x *bp, struct bnx2x_fastpath *fp,
+                              u16 index, gfp_t gfp_mask)
 {
-        struct page *page = alloc_pages(GFP_ATOMIC, PAGES_PER_SGE_SHIFT);
+        struct page *page = alloc_pages(gfp_mask, PAGES_PER_SGE_SHIFT);
         struct sw_rx_page *sw_buf = &fp->rx_page_ring[index];
         struct eth_rx_sge *sge = &fp->rx_sge_ring[index];
         dma_addr_t mapping;
@@ -572,7 +572,7 @@ static int bnx2x_fill_frag_skb(struct bnx2x *bp, struct bnx2x_fastpath *fp,
 
                 /* If we fail to allocate a substitute page, we simply stop
                    where we are and drop the whole packet */
-                err = bnx2x_alloc_rx_sge(bp, fp, sge_idx);
+                err = bnx2x_alloc_rx_sge(bp, fp, sge_idx, GFP_ATOMIC);
                 if (unlikely(err)) {
                         bnx2x_fp_qstats(bp, fp)->rx_skb_alloc_failed++;
                         return err;
@@ -616,12 +616,17 @@ static void bnx2x_frag_free(const struct bnx2x_fastpath *fp, void *data)
                 kfree(data);
 }
 
-static void *bnx2x_frag_alloc(const struct bnx2x_fastpath *fp)
+static void *bnx2x_frag_alloc(const struct bnx2x_fastpath *fp, gfp_t gfp_mask)
 {
-        if (fp->rx_frag_size)
+        if (fp->rx_frag_size) {
+                /* GFP_KERNEL allocations are used only during initialization */
+                if (unlikely(gfp_mask & __GFP_WAIT))
+                        return (void *)__get_free_page(gfp_mask);
+
                 return netdev_alloc_frag(fp->rx_frag_size);
+        }
 
-        return kmalloc(fp->rx_buf_size + NET_SKB_PAD, GFP_ATOMIC);
+        return kmalloc(fp->rx_buf_size + NET_SKB_PAD, gfp_mask);
 }
 
 #ifdef CONFIG_INET
@@ -701,7 +706,7 @@ static void bnx2x_tpa_stop(struct bnx2x *bp, struct bnx2x_fastpath *fp,
                 goto drop;
 
         /* Try to allocate the new data */
-        new_data = bnx2x_frag_alloc(fp);
+        new_data = bnx2x_frag_alloc(fp, GFP_ATOMIC);
         /* Unmap skb in the pool anyway, as we are going to change
            pool entry status to BNX2X_TPA_STOP even if new skb allocation
            fails. */
@@ -752,15 +757,15 @@ drop:
         bnx2x_fp_stats(bp, fp)->eth_q_stats.rx_skb_alloc_failed++;
 }
 
-static int bnx2x_alloc_rx_data(struct bnx2x *bp,
-                               struct bnx2x_fastpath *fp, u16 index)
+static int bnx2x_alloc_rx_data(struct bnx2x *bp, struct bnx2x_fastpath *fp,
+                               u16 index, gfp_t gfp_mask)
 {
         u8 *data;
         struct sw_rx_bd *rx_buf = &fp->rx_buf_ring[index];
         struct eth_rx_bd *rx_bd = &fp->rx_desc_ring[index];
         dma_addr_t mapping;
 
-        data = bnx2x_frag_alloc(fp);
+        data = bnx2x_frag_alloc(fp, gfp_mask);
         if (unlikely(data == NULL))
                 return -ENOMEM;
 
@@ -953,7 +958,8 @@ int bnx2x_rx_int(struct bnx2x_fastpath *fp, int budget)
                         memcpy(skb->data, data + pad, len);
                         bnx2x_reuse_rx_data(fp, bd_cons, bd_prod);
                 } else {
-                        if (likely(bnx2x_alloc_rx_data(bp, fp, bd_prod) == 0)) {
+                        if (likely(bnx2x_alloc_rx_data(bp, fp, bd_prod,
+                                                       GFP_ATOMIC) == 0)) {
                                 dma_unmap_single(&bp->pdev->dev,
                                                  dma_unmap_addr(rx_buf, mapping),
                                                  fp->rx_buf_size,
@@ -1313,7 +1319,8 @@ void bnx2x_init_rx_rings(struct bnx2x *bp)
                                 struct sw_rx_bd *first_buf =
                                         &tpa_info->first_buf;
 
-                                first_buf->data = bnx2x_frag_alloc(fp);
+                                first_buf->data =
+                                        bnx2x_frag_alloc(fp, GFP_KERNEL);
                                 if (!first_buf->data) {
                                         BNX2X_ERR("Failed to allocate TPA skb pool for queue[%d] - disabling TPA on this queue!\n",
                                                   j);
@@ -1335,7 +1342,8 @@ void bnx2x_init_rx_rings(struct bnx2x *bp)
                         for (i = 0, ring_prod = 0;
                              i < MAX_RX_SGE_CNT*NUM_RX_SGE_PAGES; i++) {
 
-                                if (bnx2x_alloc_rx_sge(bp, fp, ring_prod) < 0) {
+                                if (bnx2x_alloc_rx_sge(bp, fp, ring_prod,
+                                                       GFP_KERNEL) < 0) {
                                         BNX2X_ERR("was only able to allocate %d rx sges\n",
                                                   i);
                                         BNX2X_ERR("disabling TPA for queue[%d]\n",
@@ -4221,7 +4229,7 @@ static int bnx2x_alloc_rx_bds(struct bnx2x_fastpath *fp,
          * fp->eth_q_stats.rx_skb_alloc_failed = 0
          */
         for (i = 0; i < rx_ring_size; i++) {
-                if (bnx2x_alloc_rx_data(bp, fp, ring_prod) < 0) {
+                if (bnx2x_alloc_rx_data(bp, fp, ring_prod, GFP_KERNEL) < 0) {
                         failure_cnt++;
                         continue;
                 }