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authorSathya Perla2011-08-22 19:41:53 +0000
committerDavid S. Miller2011-08-24 16:19:29 -0700
commit09c1c68f2239dcd99b76be2c44e84811fba273db (patch)
treebbbede1f08fb5663a39528deabae91a20cef8969 /drivers/net/ethernet/emulex
parentdb3ea7819d035ff01c8260fce364511adfae0eaa (diff)
be2net: fix erx->rx_drops_no_frags wrap around
The rx_drops_no_frags HW counter for RSS rings is 16bits in HW and can wraparound often. Maintain a 32-bit accumulator in the driver to prevent frequent wraparound. Also, incorporated Eric's feedback to use ACCESS_ONCE() for the accumulator write. Signed-off-by: Sathya Perla <sathya.perla@emulex.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/emulex')
-rw-r--r--drivers/net/ethernet/emulex/benet/be_main.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index 2375c0c3d1b3..fb2eda08a094 100644
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -378,6 +378,18 @@ static void populate_lancer_stats(struct be_adapter *adapter)
pport_stats->rx_drops_too_many_frags_lo;
}
+static void accumulate_16bit_val(u32 *acc, u16 val)
+{
+#define lo(x) (x & 0xFFFF)
+#define hi(x) (x & 0xFFFF0000)
+ bool wrapped = val < lo(*acc);
+ u32 newacc = hi(*acc) + val;
+
+ if (wrapped)
+ newacc += 65536;
+ ACCESS_ONCE(*acc) = newacc;
+}
+
void be_parse_stats(struct be_adapter *adapter)
{
struct be_erx_stats_v1 *erx = be_erx_stats_from_cmd(adapter);
@@ -394,9 +406,13 @@ void be_parse_stats(struct be_adapter *adapter)
}
/* as erx_v1 is longer than v0, ok to use v1 defn for v0 access */
- for_all_rx_queues(adapter, rxo, i)
- rx_stats(rxo)->rx_drops_no_frags =
- erx->rx_drops_no_fragments[rxo->q.id];
+ for_all_rx_queues(adapter, rxo, i) {
+ /* below erx HW counter can actually wrap around after
+ * 65535. Driver accumulates a 32-bit value
+ */
+ accumulate_16bit_val(&rx_stats(rxo)->rx_drops_no_frags,
+ (u16)erx->rx_drops_no_fragments[rxo->q.id]);
+ }
}
static struct rtnl_link_stats64 *be_get_stats64(struct net_device *netdev,