[v3,03/12] net: mana: Handle vport sharing between devices

Commit Message

Long Li June 12, 2022, 9:14 p.m. UTC

From: Long Li <[e-mail]>

For outgoing packets, the PF requires the VF to configure the vport with
corresponding protection domain and doorbell ID for the kernel or user
context. The vport can't be shared between different contexts.

Implement the logic to exclusively take over the vport by either the
Ethernet device or RDMA device.

Signed-off-by: Long Li <[e-mail]>
---
Change log:
v2: use refcount instead of directly using atomic variables

 drivers/net/ethernet/microsoft/mana/mana.h    |  4 +++
 drivers/net/ethernet/microsoft/mana/mana_en.c | 27 +++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

Comments

David Miller June 13, 2022, 10:50 a.m. UTC | #1

From: [e-mail]
Date: Sun, 12 Jun 2022 14:14:45 -0700

> +int mana_cfg_vport(struct mana_port_context *apc, u32 protection_dom_id,
> +		   u32 doorbell_pg_id)
>  {
> +	/* Ethernet driver and IB driver can't take the port at the same time */
> +	refcount_inc(&apc->port_use_count);
> +	if (refcount_read(&apc->port_use_count) > 2) {

This is a racy test, the count could change after the test against
'2'.  It would be nice if there was a primitive to do the increment
and test atomically, but I fail to see one that matches this scenerio
currently.

Thank you.

Long Li June 13, 2022, 6:25 p.m. UTC | #2

> Subject: Re: [Patch v3 03/12] net: mana: Handle vport sharing between
> devices
> 
> From: [e-mail]
> Date: Sun, 12 Jun 2022 14:14:45 -0700
> 
> > +int mana_cfg_vport(struct mana_port_context *apc, u32
> protection_dom_id,
> > +		   u32 doorbell_pg_id)
> >  {
> > +	/* Ethernet driver and IB driver can't take the port at the same time
> */
> > +	refcount_inc(&apc->port_use_count);
> > +	if (refcount_read(&apc->port_use_count) > 2) {
> 
> This is a racy test, the count could change after the test against '2'.  It would
> be nice if there was a primitive to do the increment and test atomically, but I
> fail to see one that matches this scenerio currently.
> 
> Thank you.

I'm changing it to mutex.

Thank you,

Long

Patch

diff --git a/drivers/net/ethernet/microsoft/mana/mana.h b/drivers/net/ethernet/microsoft/mana/mana.h
index 51bff91b63ee..6aacbf42aeaf 100644
--- a/drivers/net/ethernet/microsoft/mana/mana.h
+++ b/drivers/net/ethernet/microsoft/mana/mana.h
@@ -375,6 +375,7 @@  struct mana_port_context {
 	unsigned int num_queues;
 
 	mana_handle_t port_handle;
+	refcount_t port_use_count;
 
 	u16 port_idx;
 
@@ -567,4 +568,7 @@  struct mana_adev {
 	struct gdma_dev *mdev;
 };
 
+int mana_cfg_vport(struct mana_port_context *apc, u32 protection_dom_id,
+		   u32 doorbell_pg_id);
+void mana_uncfg_vport(struct mana_port_context *apc);
 #endif /* _MANA_H */
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 745a9783dd70..839f7099ac2d 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -530,13 +530,26 @@  static int mana_query_vport_cfg(struct mana_port_context *apc, u32 vport_index,
 	return 0;
 }
 
-static int mana_cfg_vport(struct mana_port_context *apc, u32 protection_dom_id,
-			  u32 doorbell_pg_id)
+void mana_uncfg_vport(struct mana_port_context *apc)
+{
+	refcount_dec(&apc->port_use_count);
+}
+EXPORT_SYMBOL_GPL(mana_uncfg_vport);
+
+int mana_cfg_vport(struct mana_port_context *apc, u32 protection_dom_id,
+		   u32 doorbell_pg_id)
 {
 	struct mana_config_vport_resp resp = {};
 	struct mana_config_vport_req req = {};
 	int err;
 
+	/* Ethernet driver and IB driver can't take the port at the same time */
+	refcount_inc(&apc->port_use_count);
+	if (refcount_read(&apc->port_use_count) > 2) {
+		refcount_dec(&apc->port_use_count);
+		return -ENODEV;
+	}
+
 	mana_gd_init_req_hdr(&req.hdr, MANA_CONFIG_VPORT_TX,
 			     sizeof(req), sizeof(resp));
 	req.vport = apc->port_handle;
@@ -563,9 +576,13 @@  static int mana_cfg_vport(struct mana_port_context *apc, u32 protection_dom_id,
 
 	apc->tx_shortform_allowed = resp.short_form_allowed;
 	apc->tx_vp_offset = resp.tx_vport_offset;
+
+	netdev_info(apc->ndev, "Configured vPort %llu PD %u DB %u\n",
+		    apc->port_handle, protection_dom_id, doorbell_pg_id);
 out:
 	return err;
 }
+EXPORT_SYMBOL_GPL(mana_cfg_vport);
 
 static int mana_cfg_vport_steering(struct mana_port_context *apc,
 				   enum TRI_STATE rx,
@@ -626,6 +643,9 @@  static int mana_cfg_vport_steering(struct mana_port_context *apc,
 			   resp.hdr.status);
 		err = -EPROTO;
 	}
+
+	netdev_info(ndev, "Configured steering vPort %llu entries %u\n",
+		    apc->port_handle, num_entries);
 out:
 	kfree(req);
 	return err;
@@ -1678,6 +1698,8 @@  static void mana_destroy_vport(struct mana_port_context *apc)
 	}
 
 	mana_destroy_txq(apc);
+
+	mana_uncfg_vport(apc);
 }
 
 static int mana_create_vport(struct mana_port_context *apc,
@@ -1928,6 +1950,7 @@  static int mana_probe_port(struct mana_context *ac, int port_idx,
 	apc->num_queues = gc->max_num_queues;
 	apc->port_handle = INVALID_MANA_HANDLE;
 	apc->port_idx = port_idx;
+	refcount_set(&apc->port_use_count, 1);
 
 	ndev->netdev_ops = &mana_devops;
 	ndev->ethtool_ops = &mana_ethtool_ops;