[PATCH net-next v1 4/7] net: dsa: microchip: ksz8_r_sta_mac_table(): Avoid using error code for empty entries

From: Oleksij Rempel
Date: Tue Apr 04 2023 - 06:19:37 EST


Prepare for the next patch by ensuring that ksz8_r_sta_mac_table() does
not use error codes for empty entries. This change will enable better
handling of read/write errors in the upcoming patch.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
drivers/net/dsa/microchip/ksz8795.c | 87 +++++++++++++++++------------
1 file changed, 50 insertions(+), 37 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz8795.c b/drivers/net/dsa/microchip/ksz8795.c
index fc079d6eee80..4dcf68a7f6c0 100644
--- a/drivers/net/dsa/microchip/ksz8795.c
+++ b/drivers/net/dsa/microchip/ksz8795.c
@@ -458,7 +458,7 @@ int ksz8_r_dyn_mac_table(struct ksz_device *dev, u16 addr, u8 *mac_addr,
}

static int ksz8_r_sta_mac_table(struct ksz_device *dev, u16 addr,
- struct alu_struct *alu)
+ struct alu_struct *alu, bool *valid)
{
u32 data_hi, data_lo;
const u8 *shifts;
@@ -471,28 +471,32 @@ static int ksz8_r_sta_mac_table(struct ksz_device *dev, u16 addr,
ksz8_r_table(dev, TABLE_STATIC_MAC, addr, &data);
data_hi = data >> 32;
data_lo = (u32)data;
- if (data_hi & (masks[STATIC_MAC_TABLE_VALID] |
- masks[STATIC_MAC_TABLE_OVERRIDE])) {
- alu->mac[5] = (u8)data_lo;
- alu->mac[4] = (u8)(data_lo >> 8);
- alu->mac[3] = (u8)(data_lo >> 16);
- alu->mac[2] = (u8)(data_lo >> 24);
- alu->mac[1] = (u8)data_hi;
- alu->mac[0] = (u8)(data_hi >> 8);
- alu->port_forward =
- (data_hi & masks[STATIC_MAC_TABLE_FWD_PORTS]) >>
- shifts[STATIC_MAC_FWD_PORTS];
- alu->is_override =
- (data_hi & masks[STATIC_MAC_TABLE_OVERRIDE]) ? 1 : 0;
- data_hi >>= 1;
- alu->is_static = true;
- alu->is_use_fid =
- (data_hi & masks[STATIC_MAC_TABLE_USE_FID]) ? 1 : 0;
- alu->fid = (data_hi & masks[STATIC_MAC_TABLE_FID]) >>
- shifts[STATIC_MAC_FID];
+
+ if (!(data_hi & (masks[STATIC_MAC_TABLE_VALID] |
+ masks[STATIC_MAC_TABLE_OVERRIDE]))) {
+ *valid = false;
return 0;
}
- return -ENXIO;
+
+ alu->mac[5] = (u8)data_lo;
+ alu->mac[4] = (u8)(data_lo >> 8);
+ alu->mac[3] = (u8)(data_lo >> 16);
+ alu->mac[2] = (u8)(data_lo >> 24);
+ alu->mac[1] = (u8)data_hi;
+ alu->mac[0] = (u8)(data_hi >> 8);
+ alu->port_forward =
+ (data_hi & masks[STATIC_MAC_TABLE_FWD_PORTS]) >>
+ shifts[STATIC_MAC_FWD_PORTS];
+ alu->is_override = (data_hi & masks[STATIC_MAC_TABLE_OVERRIDE]) ? 1 : 0;
+ data_hi >>= 1;
+ alu->is_static = true;
+ alu->is_use_fid = (data_hi & masks[STATIC_MAC_TABLE_USE_FID]) ? 1 : 0;
+ alu->fid = (data_hi & masks[STATIC_MAC_TABLE_FID]) >>
+ shifts[STATIC_MAC_FID];
+
+ *valid = true;
+
+ return 0;
}

void ksz8_w_sta_mac_table(struct ksz_device *dev, u16 addr,
@@ -993,20 +997,25 @@ static int ksz8_add_sta_mac(struct ksz_device *dev, int port,
const unsigned char *addr, u16 vid)
{
struct alu_struct alu;
- int index;
+ int index, ret;
int empty = 0;

alu.port_forward = 0;
for (index = 0; index < dev->info->num_statics; index++) {
- if (!ksz8_r_sta_mac_table(dev, index, &alu)) {
- /* Found one already in static MAC table. */
- if (!memcmp(alu.mac, addr, ETH_ALEN) &&
- alu.fid == vid)
- break;
- /* Remember the first empty entry. */
- } else if (!empty) {
- empty = index + 1;
+ bool valid;
+
+ ret = ksz8_r_sta_mac_table(dev, index, &alu, &valid);
+ if (ret)
+ return ret;
+ if (!valid) {
+ /* Remember the first empty entry. */
+ if (!empty)
+ empty = index + 1;
+ continue;
}
+
+ if (!memcmp(alu.mac, addr, ETH_ALEN) && alu.fid == vid)
+ break;
}

/* no available entry */
@@ -1036,15 +1045,19 @@ static int ksz8_del_sta_mac(struct ksz_device *dev, int port,
const unsigned char *addr, u16 vid)
{
struct alu_struct alu;
- int index;
+ int index, ret;

for (index = 0; index < dev->info->num_statics; index++) {
- if (!ksz8_r_sta_mac_table(dev, index, &alu)) {
- /* Found one already in static MAC table. */
- if (!memcmp(alu.mac, addr, ETH_ALEN) &&
- alu.fid == vid)
- break;
- }
+ bool valid;
+
+ ret = ksz8_r_sta_mac_table(dev, index, &alu, &valid);
+ if (ret)
+ return ret;
+ if (!valid)
+ continue;
+
+ if (!memcmp(alu.mac, addr, ETH_ALEN) && alu.fid == vid)
+ break;
}

/* no available entry */
--
2.39.2