aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLennert Buytenhek <buytenh@wantstofly.org>2009-04-29 11:58:18 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2009-05-08 14:54:36 -0700
commita239571a953830dbf73f2fcdee6731b5483c77d6 (patch)
treebcc15c4b51f49a73db0489b1f7a9e472370c1bff
parent0d8f4f2015d4f9ea3057e2d521084944306e91df (diff)
mv643xx_eth: 64bit mib counter read fix
commit 93af7aca44f0e82e67bda10a0fb73d383edcc8bd upstream. On several mv643xx_eth hardware versions, the two 64bit mib counters for 'good octets received' and 'good octets sent' are actually 32bit counters, and reading from the upper half of the register has the same effect as reading from the lower half of the register: an atomic read-and-clear of the entire 32bit counter value. This can under heavy traffic occasionally lead to small numbers being added to the upper half of the 64bit mib counter even though no 32bit wrap has occured. Since we poll the mib counters at least every 30 seconds anyway, we might as well just skip the reads of the upper halves of the hardware counters without breaking the stats, which this patch does. Signed-off-by: Lennert Buytenhek <buytenh@marvell.com> Cc: stable@kernel.org Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/net/mv643xx_eth.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index 0a18b9e96da..abd5a89a876 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -1060,7 +1060,6 @@ static void mib_counters_update(struct mv643xx_eth_private *mp)
struct mib_counters *p = &mp->mib_counters;
p->good_octets_received += mib_read(mp, 0x00);
- p->good_octets_received += (u64)mib_read(mp, 0x04) << 32;
p->bad_octets_received += mib_read(mp, 0x08);
p->internal_mac_transmit_err += mib_read(mp, 0x0c);
p->good_frames_received += mib_read(mp, 0x10);
@@ -1074,7 +1073,6 @@ static void mib_counters_update(struct mv643xx_eth_private *mp)
p->frames_512_to_1023_octets += mib_read(mp, 0x30);
p->frames_1024_to_max_octets += mib_read(mp, 0x34);
p->good_octets_sent += mib_read(mp, 0x38);
- p->good_octets_sent += (u64)mib_read(mp, 0x3c) << 32;
p->good_frames_sent += mib_read(mp, 0x40);
p->excessive_collision += mib_read(mp, 0x44);
p->multicast_frames_sent += mib_read(mp, 0x48);