Subject: [PATCH net-next 1/3] ice: add ice_adapter for shared data across PFs on the same NIC

From: Michal Schmidt <[email-masked]>
Date: Mon, 26 Feb 2024 16:11:23 +0100

There is a need for synchronization between ice PFs on the same physical
adapter.

Add a "struct ice_adapter" for holding data shared between PFs of the
same multifunction PCI device. The struct is refcounted - each ice_pf
holds a reference to it.

Its first use will be for PTP. I expect it will be useful also to
improve the ugliness that is ice_prot_id_tbl.

Signed-off-by: Michal Schmidt <[email-masked]>
---
 drivers/net/ethernet/intel/ice/Makefile      |  3 +-
 drivers/net/ethernet/intel/ice/ice.h         |  2 +
 drivers/net/ethernet/intel/ice/ice_adapter.c | 67 ++++++++++++++++++++
 drivers/net/ethernet/intel/ice/ice_adapter.h | 22 +++++++
 drivers/net/ethernet/intel/ice/ice_main.c    |  8 +++
 5 files changed, 101 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/ethernet/intel/ice/ice_adapter.c
 create mode 100644 drivers/net/ethernet/intel/ice/ice_adapter.h

diff --git a/drivers/net/ethernet/intel/ice/Makefile b/drivers/net/ethernet/intel/ice/Makefile
index cddd82d4ca0f..4fa09c321440 100644
--- a/drivers/net/ethernet/intel/ice/Makefile
+++ b/drivers/net/ethernet/intel/ice/Makefile
@@ -36,7 +36,8 @@ ice-y := ice_main.o	\
 	 ice_repr.o	\
 	 ice_tc_lib.o	\
 	 ice_fwlog.o	\
-	 ice_debugfs.o
+	 ice_debugfs.o  \
+	 ice_adapter.o
 ice-$(CONFIG_PCI_IOV) +=	\
 	ice_sriov.o		\
 	ice_virtchnl.o		\
diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index 365c03d1c462..1ffecbdd361a 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -77,6 +77,7 @@
 #include "ice_gnss.h"
 #include "ice_irq.h"
 #include "ice_dpll.h"
+#include "ice_adapter.h"
 
 #define ICE_BAR0		0
 #define ICE_REQ_DESC_MULTIPLE	32
@@ -544,6 +545,7 @@ struct ice_agg_node {
 
 struct ice_pf {
 	struct pci_dev *pdev;
+	struct ice_adapter *adapter;
 
 	struct devlink_region *nvm_region;
 	struct devlink_region *sram_region;
diff --git a/drivers/net/ethernet/intel/ice/ice_adapter.c b/drivers/net/ethernet/intel/ice/ice_adapter.c
new file mode 100644
index 000000000000..deb063401238
--- /dev/null
+++ b/drivers/net/ethernet/intel/ice/ice_adapter.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: Copyright Red Hat
+
+#include <linux/cleanup.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/xarray.h>
+#include "ice_adapter.h"
+
+static DEFINE_MUTEX(ice_adapters_lock);
+static DEFINE_XARRAY(ice_adapters);
+
+static unsigned long ice_adapter_index(const struct pci_dev *pdev)
+{
+	unsigned int domain = pci_domain_nr(pdev->bus);
+
+	WARN_ON((unsigned long)domain >> (BITS_PER_LONG - 13));
+	return ((unsigned long)domain << 13) |
+	       ((unsigned long)pdev->bus->number << 5) |
+	       PCI_SLOT(pdev->devfn);
+}
+
+struct ice_adapter *ice_adapter_get(const struct pci_dev *pdev)
+{
+	unsigned long index = ice_adapter_index(pdev);
+	struct ice_adapter *a;
+
+	guard(mutex)(&ice_adapters_lock);
+
+	a = xa_load(&ice_adapters, index);
+	if (a) {
+		refcount_inc(&a->refcount);
+		return a;
+	}
+
+	a = kzalloc(sizeof(*a), GFP_KERNEL);
+	if (!a)
+		return NULL;
+
+	refcount_set(&a->refcount, 1);
+
+	if (xa_is_err(xa_store(&ice_adapters, index, a, GFP_KERNEL))) {
+		kfree(a);
+		return NULL;
+	}
+
+	return a;
+}
+
+void ice_adapter_put(const struct pci_dev *pdev)
+{
+	unsigned long index = ice_adapter_index(pdev);
+	struct ice_adapter *a;
+
+	guard(mutex)(&ice_adapters_lock);
+
+	a = xa_load(&ice_adapters, index);
+	if (WARN_ON(!a))
+		return;
+
+	if (!refcount_dec_and_test(&a->refcount))
+		return;
+
+	WARN_ON(xa_erase(&ice_adapters, index) != a);
+	kfree(a);
+}
diff --git a/drivers/net/ethernet/intel/ice/ice_adapter.h b/drivers/net/ethernet/intel/ice/ice_adapter.h
new file mode 100644
index 000000000000..cb5a02eb24c1
--- /dev/null
+++ b/drivers/net/ethernet/intel/ice/ice_adapter.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* SPDX-FileCopyrightText: Copyright Red Hat */
+
+#ifndef _ICE_ADAPTER_H_
+#define _ICE_ADAPTER_H_
+
+#include <linux/refcount_types.h>
+
+struct pci_dev;
+
+/**
+ * struct ice_adapter - PCI adapter resources shared across PFs
+ * @refcount: Reference count. struct ice_pf objects hold the references.
+ */
+struct ice_adapter {
+	refcount_t refcount;
+};
+
+struct ice_adapter *ice_adapter_get(const struct pci_dev *pdev);
+void ice_adapter_put(const struct pci_dev *pdev);
+
+#endif /* _ICE_ADAPTER_H */
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 9c2c8637b4a7..4a60957221fc 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -5093,6 +5093,7 @@ static int
 ice_probe(struct pci_dev *pdev, const struct pci_device_id __always_unused *ent)
 {
 	struct device *dev = &pdev->dev;
+	struct ice_adapter *adapter;
 	struct ice_pf *pf;
 	struct ice_hw *hw;
 	int err;
@@ -5145,7 +5146,12 @@ ice_probe(struct pci_dev *pdev, const struct pci_device_id __always_unused *ent)
 
 	pci_set_master(pdev);
 
+	adapter = ice_adapter_get(pdev);
+	if (!adapter)
+		return -ENOMEM;
+
 	pf->pdev = pdev;
+	pf->adapter = adapter;
 	pci_set_drvdata(pdev, pf);
 	set_bit(ICE_DOWN, pf->state);
 	/* Disable service task until DOWN bit is cleared */
@@ -5196,6 +5202,7 @@ ice_probe(struct pci_dev *pdev, const struct pci_device_id __always_unused *ent)
 err_load:
 	ice_deinit(pf);
 err_init:
+	ice_adapter_put(pdev);
 	pci_disable_device(pdev);
 	return err;
 }
@@ -5302,6 +5309,7 @@ static void ice_remove(struct pci_dev *pdev)
 	ice_setup_mc_magic_wake(pf);
 	ice_set_wake(pf);
 
+	ice_adapter_put(pdev);
 	pci_disable_device(pdev);
 }
 
-- 
2.43.2