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Subject[PATCH net 4/4] net: dsa: b53: Rework ARL bin logic
Date
When asking the ARL to read a MAC address, we will get a number of bins
returned in a single read. Out of those bins, there can essentially be 3
states:

- all bins are full, we have no space left, and we can either replace an
existing address or return that full condition

- the MAC address was found, then we need to return its bin index and
modify that one, and only that one

- the MAC address was not found and we have a least one bin free, we use
that bin index location then

The code would unfortunately fail on all counts.

Fixes: 1da6df85c6fb ("net: dsa: b53: Implement ARL add/del/dump operations")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
drivers/net/dsa/b53/b53_common.c | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index e937bf365490..b2b2c4a301bf 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -1483,6 +1483,7 @@ static int b53_arl_read(struct b53_device *dev, u64 mac,
u16 vid, struct b53_arl_entry *ent, u8 *idx,
bool is_valid)
{
+ DECLARE_BITMAP(free_bins, dev->num_arl_entries);
unsigned int i;
int ret;

@@ -1490,6 +1491,8 @@ static int b53_arl_read(struct b53_device *dev, u64 mac,
if (ret)
return ret;

+ bitmap_zero(free_bins, dev->num_arl_entries);
+
/* Read the bins */
for (i = 0; i < dev->num_arl_entries; i++) {
u64 mac_vid;
@@ -1501,16 +1504,24 @@ static int b53_arl_read(struct b53_device *dev, u64 mac,
B53_ARLTBL_DATA_ENTRY(i), &fwd_entry);
b53_arl_to_entry(ent, mac_vid, fwd_entry);

- if (!(fwd_entry & ARLTBL_VALID))
+ if (!(fwd_entry & ARLTBL_VALID)) {
+ set_bit(i, free_bins);
continue;
+ }
if ((mac_vid & ARLTBL_MAC_MASK) != mac)
continue;
if (dev->vlan_enabled &&
((mac_vid >> ARLTBL_VID_S) & ARLTBL_VID_MASK) != vid)
continue;
*idx = i;
+ return 0;
}

+ if (bitmap_weight(free_bins, dev->num_arl_entries) == 0)
+ return -ENOSPC;
+
+ *idx = find_first_bit(free_bins, dev->num_arl_entries);
+
return -ENOENT;
}

@@ -1537,13 +1548,21 @@ static int b53_arl_op(struct b53_device *dev, int op, int port,

ret = b53_arl_read(dev, mac, vid, &ent, &idx, is_valid);
/* If this is a read, just finish now */
- if (op)
+ if (op && ret != -ENOENT)
return ret;

/* We could not find a matching MAC, so reset to a new entry */
- if (ret) {
+ switch (ret) {
+ case -ENOSPC:
+ dev_warn(dev->dev, "no space left in ARL\n");
+ return ret;
+ case -ENOENT:
+ dev_dbg(dev->dev, "{%pM,%.4d} not found, using idx: %d\n", addr, vid, idx);
fwd_entry = 0;
- idx = 1;
+ break;
+ default:
+ dev_dbg(dev->dev, "{%pM,%.4d} found, using idx: %d\n", addr, vid, idx);
+ break;
}

/* For multicast address, the port is a bitmask and the validity
--
2.17.1
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