[PATCH 5.4 084/367] mlxsw: i2c: Limit single transaction buffer size

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5.4-stable review patch.  If anyone has any objections, please let me know.


From: Vadim Pasternak <vadimp@xxxxxxxxxx>

[ Upstream commit d7248f1cc835bd80e936dc5b2d94b149bdd0077d ]

Maximum size of buffer is obtained from underlying I2C adapter and in
case adapter allows I2C transaction buffer size greater than 100 bytes,
transaction will fail due to firmware limitation.

As a result driver will fail initialization.

Limit the maximum size of transaction buffer by 100 bytes to fit to

Remove unnecessary calculation:
max_t(u16, MLXSW_I2C_BLK_DEF, quirk_size).
This condition can not happened.

Fixes: 3029a693beda ("mlxsw: i2c: Allow flexible setting of I2C transactions size")
Signed-off-by: Vadim Pasternak <vadimp@xxxxxxxxxx>
Reviewed-by: Petr Machata <petrm@xxxxxxxxxx>
Signed-off-by: Petr Machata <petrm@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
 drivers/net/ethernet/mellanox/mlxsw/i2c.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/i2c.c b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
index 65976a3ab591e..b0d44b1361161 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/i2c.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
@@ -47,6 +47,7 @@
 #define MLXSW_I2C_BLK_DEF		32
+#define MLXSW_I2C_BLK_MAX		100
 #define MLXSW_I2C_RETRY			5
 #define MLXSW_I2C_TIMEOUT_MSECS		5000
 #define MLXSW_I2C_MAX_DATA_SIZE		256
@@ -575,7 +576,7 @@ static int mlxsw_i2c_probe(struct i2c_client *client,
 			return -EOPNOTSUPP;
-		mlxsw_i2c->block_size = max_t(u16, MLXSW_I2C_BLK_DEF,
+		mlxsw_i2c->block_size = min_t(u16, MLXSW_I2C_BLK_MAX,
 					      min_t(u16, quirks->max_read_len,
 	} else {

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