diff mbox series

[v4,net-next,2/3] net: dsa: mv88e6xxx: shorten the locked section in mv88e6xxx_g1_atu_prob_irq_thread_fn()

Message ID 20230108094849.1789162-3-netdev@kapio-technology.com
State New
Headers
Series mv88e6xxx: Add MAB offload support |

Commit Message

Hans Schultz Jan. 8, 2023, 9:48 a.m. UTC 
  As only the hardware access functions up til and including
mv88e6xxx_g1_atu_mac_read() called under the interrupt handler
need to take the chip lock, we release the chip lock after this call.
The follow up code that handles the violations can run without the
chip lock held.
In further patches, the violation handler function will even be
incompatible with having the chip lock held. This due to an AB/BA
ordering inversion with rtnl_lock().

Signed-off-by: Hans J. Schultz <netdev@kapio-technology.com>
---
 drivers/net/dsa/mv88e6xxx/global1_atu.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Vladimir Oltean Jan. 9, 2023, 1:29 p.m. UTC | #1 
On Sun, Jan 08, 2023 at 10:48:48AM +0100, Hans J. Schultz wrote:
> As only the hardware access functions up til and including
> mv88e6xxx_g1_atu_mac_read() called under the interrupt handler
> need to take the chip lock, we release the chip lock after this call.
> The follow up code that handles the violations can run without the
> chip lock held.
> In further patches, the violation handler function will even be
> incompatible with having the chip lock held. This due to an AB/BA
> ordering inversion with rtnl_lock().
> 
> Signed-off-by: Hans J. Schultz <netdev@kapio-technology.com>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
diff mbox series

Patch

diff --git a/drivers/net/dsa/mv88e6xxx/global1_atu.c b/drivers/net/dsa/mv88e6xxx/global1_atu.c
index 61ae2d61e25c..0a9fd253c727 100644
--- a/drivers/net/dsa/mv88e6xxx/global1_atu.c
+++ b/drivers/net/dsa/mv88e6xxx/global1_atu.c
@@ -409,23 +409,25 @@  static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 
 	err = mv88e6xxx_g1_read_atu_violation(chip);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_read(chip, MV88E6XXX_G1_ATU_OP, &val);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_atu_fid_read(chip, &fid);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_atu_data_read(chip, &entry);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_atu_mac_read(chip, &entry);
 	if (err)
-		goto out;
+		goto out_unlock;
+
+	mv88e6xxx_reg_unlock(chip);
 
 	spid = entry.state;
 
@@ -449,13 +451,11 @@  static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 						   fid);
 		chip->ports[spid].atu_full_violation++;
 	}
-	mv88e6xxx_reg_unlock(chip);
 
 	return IRQ_HANDLED;
 
-out:
+out_unlock:
 	mv88e6xxx_reg_unlock(chip);
-
 	dev_err(chip->dev, "ATU problem: error %d while handling interrupt\n",
 		err);
 	return IRQ_HANDLED;