[TG3]: Fix bug in tg3_rx()
This patch fixes a bug that causes tg3_has_work() to always return 1.
rx work is determined by comparing tp->rx_rcb_ptr with the current hw
producer index. The hw producer index is modulo the ring size, but tp-
>rx_rcb_ptr is a free running counter that goes up beyond the ring size.
After the ring wraps around once, tg3_has_work() will always return 1.
The fix is to always do modulo arithmetic on tp->rx_rcb_ptr.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index 10d4761..e53c1dc 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -2686,8 +2686,8 @@
static int tg3_rx(struct tg3 *tp, int budget)
{
u32 work_mask;
- u32 rx_rcb_ptr = tp->rx_rcb_ptr;
- u16 hw_idx, sw_idx;
+ u32 sw_idx = tp->rx_rcb_ptr;
+ u16 hw_idx;
int received;
hw_idx = tp->hw_status->idx[0].rx_producer;
@@ -2696,7 +2696,6 @@
* the opaque cookie.
*/
rmb();
- sw_idx = rx_rcb_ptr % TG3_RX_RCB_RING_SIZE(tp);
work_mask = 0;
received = 0;
while (sw_idx != hw_idx && budget > 0) {
@@ -2801,14 +2800,13 @@
next_pkt:
(*post_ptr)++;
next_pkt_nopost:
- rx_rcb_ptr++;
- sw_idx = rx_rcb_ptr % TG3_RX_RCB_RING_SIZE(tp);
+ sw_idx++;
+ sw_idx %= TG3_RX_RCB_RING_SIZE(tp);
}
/* ACK the status ring. */
- tp->rx_rcb_ptr = rx_rcb_ptr;
- tw32_rx_mbox(MAILBOX_RCVRET_CON_IDX_0 + TG3_64BIT_REG_LOW,
- (rx_rcb_ptr % TG3_RX_RCB_RING_SIZE(tp)));
+ tp->rx_rcb_ptr = sw_idx;
+ tw32_rx_mbox(MAILBOX_RCVRET_CON_IDX_0 + TG3_64BIT_REG_LOW, sw_idx);
/* Refill RX ring(s). */
if (work_mask & RXD_OPAQUE_RING_STD) {