bnx2x: organize BDs calculation for stop/resume

Put the numbers used for stop/resume queue in a single place and
fix the condition for sanity check.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
index 52f33b8c41e5..dbe97918a7fd 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
@@ -614,6 +614,22 @@ struct bnx2x_fastpath {
 #define TX_BD(x)                ((x) & MAX_TX_BD)
 #define TX_BD_POFF(x)           ((x) & MAX_TX_DESC_CNT)
 
+/* number of NEXT_PAGE descriptors may be required during placement */
+#define NEXT_CNT_PER_TX_PKT(bds)        \
+                                (((bds) + MAX_TX_DESC_CNT - 1) / \
+                                 MAX_TX_DESC_CNT * NEXT_PAGE_TX_DESC_CNT)
+/* max BDs per tx packet w/o next_pages:
+ * START_BD             - describes packed
+ * START_BD(splitted)   - includes unpaged data segment for GSO
+ * PARSING_BD           - for TSO and CSUM data
+ * Frag BDs             - decribes pages for frags
+ */
+#define BDS_PER_TX_PKT          3
+#define MAX_BDS_PER_TX_PKT      (MAX_SKB_FRAGS + BDS_PER_TX_PKT)
+/* max BDs per tx packet including next pages */
+#define MAX_DESC_PER_TX_PKT     (MAX_BDS_PER_TX_PKT + \
+                                 NEXT_CNT_PER_TX_PKT(MAX_BDS_PER_TX_PKT))
+
 /* The RX BD ring is special, each bd is 8 bytes but the last one is 16 */
 #define NUM_RX_RINGS            8
 #define RX_DESC_CNT             (BCM_PAGE_SIZE / sizeof(struct eth_rx_bd))