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* [PATCH net-next 1/1] qed: prevent a fw assert during device shutdown
@ 2022-02-09 19:28 Venkata Sudheer Kumar Bhavaraju
  2022-02-10 15:30 ` patchwork-bot+netdevbpf
  0 siblings, 1 reply; 2+ messages in thread
From: Venkata Sudheer Kumar Bhavaraju @ 2022-02-09 19:28 UTC (permalink / raw)
  To: kuba
  Cc: netdev, manishc, davem, Venkata Sudheer Kumar Bhavaraju,
	Pravin Kumar Ganesh Dhende, Alok Prasad, Ariel Elior

Device firmware can assert if the device shutdown path in driver
encounters an async. events from mfw (processed in
qed_mcp_handle_events()) after qed_mcp_unload_req() returns.
A call to qed_mcp_unload_req() currently marks the device as inactive
and thus stops any new events, but there is a windows where in-flight
events might still be received by the driver.

To prevent this race condition, atomically set QED_MCP_BYPASS_PROC_BIT
in qed_mcp_unload_req() to make sure qed_mcp_handle_events() ignores all
events. Wait for any event that might already be in-process to complete
by monitoring QED_MCP_IN_PROCESSING_BIT.

Signed-off-by: Pravin Kumar Ganesh Dhende <pdhende@marvell.com>
Signed-off-by: Venkata Sudheer Kumar Bhavaraju <vbhavaraju@marvell.com>
Signed-off-by: Alok Prasad <palok@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
---
 drivers/net/ethernet/qlogic/qed/qed_dev.c |  3 ++
 drivers/net/ethernet/qlogic/qed/qed_mcp.c | 42 +++++++++++++++++++++--
 drivers/net/ethernet/qlogic/qed/qed_mcp.h |  8 +++++
 3 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_dev.c b/drivers/net/ethernet/qlogic/qed/qed_dev.c
index cc4ec2bb36db..672480c9d195 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_dev.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_dev.c
@@ -3098,6 +3098,9 @@ int qed_hw_init(struct qed_dev *cdev, struct qed_hw_init_params *p_params)
 			continue;
 		}
 
+		/* Some flows may keep variable set */
+		p_hwfn->mcp_info->mcp_handling_status = 0;
+
 		rc = qed_calc_hw_mode(p_hwfn);
 		if (rc)
 			return rc;
diff --git a/drivers/net/ethernet/qlogic/qed/qed_mcp.c b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
index b3811ad4bcf0..9fb1fa479d4b 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
@@ -140,7 +140,7 @@ static struct qed_mcp_cmd_elem *qed_mcp_cmd_get_elem(struct qed_hwfn *p_hwfn,
 int qed_mcp_free(struct qed_hwfn *p_hwfn)
 {
 	if (p_hwfn->mcp_info) {
-		struct qed_mcp_cmd_elem *p_cmd_elem, *p_tmp;
+		struct qed_mcp_cmd_elem *p_cmd_elem = NULL, *p_tmp;
 
 		kfree(p_hwfn->mcp_info->mfw_mb_cur);
 		kfree(p_hwfn->mcp_info->mfw_mb_shadow);
@@ -249,6 +249,7 @@ int qed_mcp_cmd_init(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 	/* Initialize the MFW spinlock */
 	spin_lock_init(&p_info->cmd_lock);
 	spin_lock_init(&p_info->link_lock);
+	spin_lock_init(&p_info->unload_lock);
 
 	INIT_LIST_HEAD(&p_info->cmd_list);
 
@@ -1095,10 +1096,15 @@ int qed_mcp_load_done(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 	return 0;
 }
 
+#define MFW_COMPLETION_MAX_ITER 5000
+#define MFW_COMPLETION_INTERVAL_MS 1
+
 int qed_mcp_unload_req(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 {
 	struct qed_mcp_mb_params mb_params;
+	u32 cnt = MFW_COMPLETION_MAX_ITER;
 	u32 wol_param;
+	int rc;
 
 	switch (p_hwfn->cdev->wol_config) {
 	case QED_OV_WOL_DISABLED:
@@ -1121,7 +1127,23 @@ int qed_mcp_unload_req(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 	mb_params.param = wol_param;
 	mb_params.flags = QED_MB_FLAG_CAN_SLEEP | QED_MB_FLAG_AVOID_BLOCK;
 
-	return qed_mcp_cmd_and_union(p_hwfn, p_ptt, &mb_params);
+	spin_lock_bh(&p_hwfn->mcp_info->unload_lock);
+	set_bit(QED_MCP_BYPASS_PROC_BIT,
+		&p_hwfn->mcp_info->mcp_handling_status);
+	spin_unlock_bh(&p_hwfn->mcp_info->unload_lock);
+
+	rc = qed_mcp_cmd_and_union(p_hwfn, p_ptt, &mb_params);
+
+	while (test_bit(QED_MCP_IN_PROCESSING_BIT,
+			&p_hwfn->mcp_info->mcp_handling_status) && --cnt)
+		msleep(MFW_COMPLETION_INTERVAL_MS);
+
+	if (!cnt)
+		DP_NOTICE(p_hwfn,
+			  "Failed to wait MFW event completion after %d msec\n",
+			  MFW_COMPLETION_MAX_ITER * MFW_COMPLETION_INTERVAL_MS);
+
+	return rc;
 }
 
 int qed_mcp_unload_done(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
@@ -2021,6 +2043,19 @@ int qed_mcp_handle_events(struct qed_hwfn *p_hwfn,
 			   "Msg [%d] - old CMD 0x%02x, new CMD 0x%02x\n",
 			   i, info->mfw_mb_shadow[i], info->mfw_mb_cur[i]);
 
+		spin_lock_bh(&p_hwfn->mcp_info->unload_lock);
+		if (test_bit(QED_MCP_BYPASS_PROC_BIT,
+			     &p_hwfn->mcp_info->mcp_handling_status)) {
+			spin_unlock_bh(&p_hwfn->mcp_info->unload_lock);
+			DP_INFO(p_hwfn,
+				"Msg [%d] is bypassed on unload flow\n", i);
+			continue;
+		}
+
+		set_bit(QED_MCP_IN_PROCESSING_BIT,
+			&p_hwfn->mcp_info->mcp_handling_status);
+		spin_unlock_bh(&p_hwfn->mcp_info->unload_lock);
+
 		switch (i) {
 		case MFW_DRV_MSG_LINK_CHANGE:
 			qed_mcp_handle_link_change(p_hwfn, p_ptt, false);
@@ -2074,6 +2109,9 @@ int qed_mcp_handle_events(struct qed_hwfn *p_hwfn,
 			DP_INFO(p_hwfn, "Unimplemented MFW message %d\n", i);
 			rc = -EINVAL;
 		}
+
+		clear_bit(QED_MCP_IN_PROCESSING_BIT,
+			  &p_hwfn->mcp_info->mcp_handling_status);
 	}
 
 	/* ACK everything */
diff --git a/drivers/net/ethernet/qlogic/qed/qed_mcp.h b/drivers/net/ethernet/qlogic/qed/qed_mcp.h
index 2f26bee54e6c..9bd0565fe8ab 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.h
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.h
@@ -788,6 +788,14 @@ struct qed_mcp_info {
 
 	/* S/N for debug data mailbox commands */
 	atomic_t dbg_data_seq;
+
+	/* Spinlock used to sync the flag mcp_handling_status with
+	 * the mfw events handler
+	 */
+	spinlock_t unload_lock;
+	unsigned long mcp_handling_status;
+#define QED_MCP_BYPASS_PROC_BIT 0
+#define QED_MCP_IN_PROCESSING_BIT       1
 };
 
 struct qed_mcp_mb_params {
-- 
2.27.0


^ permalink raw reply related	[flat|nested] 2+ messages in thread
* Re: [PATCH net-next 1/1] qed: prevent a fw assert during device shutdown
  2022-02-09 19:28 [PATCH net-next 1/1] qed: prevent a fw assert during device shutdown Venkata Sudheer Kumar Bhavaraju
@ 2022-02-10 15:30 ` patchwork-bot+netdevbpf
  0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-02-10 15:30 UTC (permalink / raw)
  To: Venkata Sudheer Kumar Bhavaraju
  Cc: kuba, netdev, manishc, davem, pdhende, palok, aelior

Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Wed, 9 Feb 2022 11:28:14 -0800 you wrote:
> Device firmware can assert if the device shutdown path in driver
> encounters an async. events from mfw (processed in
> qed_mcp_handle_events()) after qed_mcp_unload_req() returns.
> A call to qed_mcp_unload_req() currently marks the device as inactive
> and thus stops any new events, but there is a windows where in-flight
> events might still be received by the driver.
> 
> [...]

Here is the summary with links:
  - [net-next,1/1] qed: prevent a fw assert during device shutdown
    https://git.kernel.org/netdev/net-next/c/ca2d5f1ff059

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



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