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Message-Id: <20231130075247.3078931-1-quan@os.amperecomputing.com>
Date: Thu, 30 Nov 2023 14:52:47 +0700
From: Quan Nguyen <quan@...amperecomputing.com>
To: Jeremy Kerr <jk@...econstruct.com.au>,
Matt Johnston <matt@...econstruct.com.au>,
"David S . Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
openbmc@...ts.ozlabs.org,
Open Source Submission <patches@...erecomputing.com>
Cc: Phong Vo <phong@...amperecomputing.com>,
Thang Nguyen <thang@...amperecomputing.com>,
Quan Nguyen <quan@...amperecomputing.com>,
Dung Cao <dung@...amperecomputing.com>
Subject: [PATCH] mctp i2c: Requeue the packet when arbitration is lost
If arbitration is lost, __i2c_transfer() returns -EAGAIN and the
packet should be resent.
Requeue the packet and increase collisions count on this case.
Co-developed-by: Dung Cao <dung@...amperecomputing.com>
Signed-off-by: Dung Cao <dung@...amperecomputing.com>
Signed-off-by: Quan Nguyen <quan@...amperecomputing.com>
---
drivers/net/mctp/mctp-i2c.c | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)
diff --git a/drivers/net/mctp/mctp-i2c.c b/drivers/net/mctp/mctp-i2c.c
index b37a9e4bade4..132023306052 100644
--- a/drivers/net/mctp/mctp-i2c.c
+++ b/drivers/net/mctp/mctp-i2c.c
@@ -442,14 +442,14 @@ static void mctp_i2c_unlock_reset(struct mctp_i2c_dev *midev)
i2c_unlock_bus(midev->adapter, I2C_LOCK_SEGMENT);
}
-static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb)
+static int mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb)
{
struct net_device_stats *stats = &midev->ndev->stats;
enum mctp_i2c_flow_state fs;
struct mctp_i2c_hdr *hdr;
struct i2c_msg msg = {0};
u8 *pecp;
- int rc;
+ int rc = 0;
fs = mctp_i2c_get_tx_flow_state(midev, skb);
@@ -461,17 +461,11 @@ static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb)
dev_warn_ratelimited(&midev->adapter->dev,
"Bad tx length %d vs skb %u\n",
hdr->byte_count + 3, skb->len);
- return;
+ return -EINVAL;
}
- if (skb_tailroom(skb) >= 1) {
- /* Linear case with space, we can just append the PEC */
- skb_put(skb, 1);
- } else {
- /* Otherwise need to copy the buffer */
- skb_copy_bits(skb, 0, midev->tx_scratch, skb->len);
- hdr = (void *)midev->tx_scratch;
- }
+ skb_copy_bits(skb, 0, midev->tx_scratch, skb->len);
+ hdr = (void *)midev->tx_scratch;
pecp = (void *)&hdr->source_slave + hdr->byte_count;
*pecp = i2c_smbus_pec(0, (u8 *)hdr, hdr->byte_count + 3);
@@ -503,17 +497,20 @@ static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb)
break;
case MCTP_I2C_TX_FLOW_INVALID:
- return;
+ return rc;
}
if (rc < 0) {
dev_warn_ratelimited(&midev->adapter->dev,
"__i2c_transfer failed %d\n", rc);
stats->tx_errors++;
+ if (rc == -EAGAIN)
+ stats->collisions++;
} else {
stats->tx_bytes += skb->len;
stats->tx_packets++;
}
+ return rc;
}
static void mctp_i2c_flow_release(struct mctp_i2c_dev *midev)
@@ -568,6 +565,7 @@ static int mctp_i2c_tx_thread(void *data)
struct mctp_i2c_dev *midev = data;
struct sk_buff *skb;
unsigned long flags;
+ int rc;
for (;;) {
if (kthread_should_stop())
@@ -583,8 +581,17 @@ static int mctp_i2c_tx_thread(void *data)
mctp_i2c_flow_release(midev);
} else if (skb) {
- mctp_i2c_xmit(midev, skb);
- kfree_skb(skb);
+ rc = mctp_i2c_xmit(midev, skb);
+ if (rc == -EAGAIN) {
+ spin_lock_irqsave(&midev->tx_queue.lock, flags);
+ if (skb_queue_len(&midev->tx_queue) >= MCTP_I2C_TX_WORK_LEN)
+ kfree_skb(skb);
+ else
+ __skb_queue_head(&midev->tx_queue, skb);
+ spin_unlock_irqrestore(&midev->tx_queue.lock, flags);
+ } else {
+ kfree_skb(skb);
+ }
} else {
wait_event_idle(midev->tx_wq,
--
2.35.1
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