enic: add wq clean up budget

In case of tx clean up, we set '-1' as budget. This means clean up until
wq is empty or till (1 << 32) pkts are cleaned. Under heavy load this
will run for long time and cause
"watchdog: BUG: soft lockup - CPU#25 stuck for 21s!" warning.

This patch sets wq clean up budget to 256.
Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cisco/enic/enic.h

@@ -43,6 +43,8 @@
 #define ENIC_CQ_MAX		(ENIC_WQ_MAX + ENIC_RQ_MAX)
 #define ENIC_INTR_MAX		(ENIC_CQ_MAX + 2)
 
+#define ENIC_WQ_NAPI_BUDGET	256
+
 #define ENIC_AIC_LARGE_PKT_DIFF	3
 
 struct enic_msix_entry {

drivers/net/ethernet/cisco/enic/enic_main.c

@@ -1500,7 +1500,7 @@ static int enic_poll(struct napi_struct *napi, int budget)
 	unsigned int cq_wq = enic_cq_wq(enic, 0);
 	unsigned int intr = enic_legacy_io_intr();
 	unsigned int rq_work_to_do = budget;
-	unsigned int wq_work_to_do = -1; /* no limit */
+	unsigned int wq_work_to_do = ENIC_WQ_NAPI_BUDGET;
 	unsigned int  work_done, rq_work_done = 0, wq_work_done;
 	int err;
 
@@ -1598,7 +1598,7 @@ static int enic_poll_msix_wq(struct napi_struct *napi, int budget)
 	struct vnic_wq *wq = &enic->wq[wq_index];
 	unsigned int cq;
 	unsigned int intr;
-	unsigned int wq_work_to_do = -1; /* clean all desc possible */
+	unsigned int wq_work_to_do = ENIC_WQ_NAPI_BUDGET;
 	unsigned int wq_work_done;
 	unsigned int wq_irq;