2010-02-01 20:29:37

by Divy Le ray

Subject: [PATCH net-next-2.6] cxgb3: add memory barriers

From: Divy Le Ray <[email protected]>

Add memory barriers to fix crashes observed on newest PowerPC platforms.
The HW and driver state of the receive rings were getting out of sync.

Signed-off-by: Divy Le Ray <[email protected]>
---

drivers/net/cxgb3/sge.c | 16 ++++++++++++----
1 files changed, 12 insertions(+), 4 deletions(-)


diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index bdbd147..4cf9b79 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -480,6 +480,7 @@ static inline void ring_fl_db(struct adapter *adap, struct sge_fl *q)
{
if (q->pend_cred >= q->credits / 4) {
q->pend_cred = 0;
+ wmb();
t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
}
}
@@ -2282,11 +2283,14 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs,
while (likely(budget_left && is_new_response(r, q))) {
int packet_complete, eth, ethpad = 2, lro = qs->lro_enabled;
struct sk_buff *skb = NULL;
- u32 len, flags = ntohl(r->flags);
- __be32 rss_hi = *(const __be32 *)r,
- rss_lo = r->rss_hdr.rss_hash_val;
+ u32 len, flags;
+ __be32 rss_hi, rss_lo;

+ rmb();
eth = r->rss_hdr.opcode == CPL_RX_PKT;
+ rss_hi = *(const __be32 *)r;
+ rss_lo = r->rss_hdr.rss_hash_val;
+ flags = ntohl(r->flags);

if (unlikely(flags & F_RSPD_ASYNC_NOTIF)) {
skb = alloc_skb(AN_PKT_SIZE, GFP_ATOMIC);
@@ -2497,7 +2501,10 @@ static int process_pure_responses(struct adapter *adap, struct sge_qset *qs,
refill_rspq(adap, q, q->credits);
q->credits = 0;
}
- } while (is_new_response(r, q) && is_pure_response(r));
+ if (!is_new_response(r, q))
+ break;
+ rmb();
+ } while (is_pure_response(r));

if (sleeping)
check_ring_db(adap, qs, sleeping);
@@ -2531,6 +2538,7 @@ static inline int handle_responses(struct adapter *adap, struct sge_rspq *q)

if (!is_new_response(r, q))
return -1;
+ rmb();
if (is_pure_response(r) && process_pure_responses(adap, qs, r) == 0) {
t3_write_reg(adap, A_SG_GTS, V_RSPQ(q->cntxt_id) |
V_NEWTIMER(q->holdoff_tmr) | V_NEWINDEX(q->cidx));

2010-02-04 02:37:09

by David Miller

Subject: Re: [PATCH net-next-2.6] cxgb3: add memory barriers

From: Divy Le Ray <[email protected]>
Date: Mon, 01 Feb 2010 12:29:29 -0800

> From: Divy Le Ray <[email protected]>
>
> Add memory barriers to fix crashes observed on newest PowerPC platforms.
> The HW and driver state of the receive rings were getting out of sync.
>
> Signed-off-by: Divy Le Ray <[email protected]>

Applied, thanks.