[RFC PATCH 16/30] PCI: endpoint: Assign function number of each PF in EPC core

[Kishon Vijay Abraham I]

The endpoint core relies on the drivers that invoke the API to bind
a controller driver with a function driver to allocate and assign a
function number to each physical function. Ideally the function
numbers should be assinged by EPC core for each of the physical
function that is bound to the EPC.

Assign function number of each PF in EPC core and remove function
number allocation in endpoint configfs.

Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
---
 drivers/pci/endpoint/pci-ep-cfs.c   | 27 +++++----------------------
 drivers/pci/endpoint/pci-epc-core.c | 12 +++++++++++-
 include/linux/pci-epc.h             |  2 ++
 3 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index d1288a0bd530..e7e8367eead1 100644
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -29,7 +29,6 @@ struct pci_epc_group {
 	struct config_group group;
 	struct pci_epc *epc;
 	bool start;
-	unsigned long function_num_map;
 };
 
 static inline struct pci_epf_group *to_pci_epf_group(struct config_item *item)
@@ -89,37 +88,22 @@ static int pci_epc_epf_link(struct config_item *epc_item,
 			    struct config_item *epf_item)
 {
 	int ret;
-	u32 func_no = 0;
 	struct pci_epf_group *epf_group = to_pci_epf_group(epf_item);
 	struct pci_epc_group *epc_group = to_pci_epc_group(epc_item);
 	struct pci_epc *epc = epc_group->epc;
 	struct pci_epf *epf = epf_group->epf;
 
-	func_no = find_first_zero_bit(&epc_group->function_num_map,
-				      BITS_PER_LONG);
-	if (func_no >= BITS_PER_LONG)
-		return -EINVAL;
-
-	set_bit(func_no, &epc_group->function_num_map);
-	epf->func_no = func_no;
-
 	ret = pci_epc_add_epf(epc, epf);
 	if (ret)
-		goto err_add_epf;
+		return ret;
 
 	ret = pci_epf_bind(epf);
-	if (ret)
-		goto err_epf_bind;
+	if (ret) {
+		pci_epc_remove_epf(epc, epf);
+		return ret;
+	}
 
 	return 0;
-
-err_epf_bind:
-	pci_epc_remove_epf(epc, epf);
-
-err_add_epf:
-	clear_bit(func_no, &epc_group->function_num_map);
-
-	return ret;
 }
 
 static void pci_epc_epf_unlink(struct config_item *epc_item,
@@ -134,7 +118,6 @@ static void pci_epc_epf_unlink(struct config_item *epc_item,
 
 	epc = epc_group->epc;
 	epf = epf_group->epf;
-	clear_bit(epf->func_no, &epc_group->function_num_map);
 	pci_epf_unbind(epf);
 	pci_epc_remove_epf(epc, epf);
 }
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index eea07f9ec5ff..e5d8d8370686 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -471,6 +471,8 @@ EXPORT_SYMBOL_GPL(pci_epc_write_header);
  */
 int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
 {
+	u32 func_no = 0;
+
 	if (epf->epc)
 		return -EBUSY;
 
@@ -480,9 +482,16 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
 	if (epf->func_no > epc->max_functions - 1)
 		return -EINVAL;
 
+	mutex_lock(&epc->lock);
+	func_no = find_first_zero_bit(&epc->function_num_map,
+				      BITS_PER_LONG);
+	if (func_no >= BITS_PER_LONG)
+		return -EINVAL;
+
+	set_bit(func_no, &epc->function_num_map);
+	epf->func_no = func_no;
 	epf->epc = epc;
 
-	mutex_lock(&epc->lock);
 	list_add_tail(&epf->list, &epc->pci_epf);
 	mutex_unlock(&epc->lock);
 
@@ -503,6 +512,7 @@ void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf)
 		return;
 
 	mutex_lock(&epc->lock);
+	clear_bit(epf->func_no, &epc->function_num_map);
 	list_del(&epf->list);
 	mutex_unlock(&epc->lock);
 }
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index a430d02aa1ff..ad118a3f1330 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -89,6 +89,7 @@ struct pci_epc_mem {
  * @max_functions: max number of functions that can be configured in this EPC
  * @group: configfs group representing the PCI EPC device
  * @lock: mutex to protect pci_epc ops
+ * @function_num_map: bitmap to manage physical function number
  * @notifier: used to notify EPF of any EPC events (like linkup)
  */
 struct pci_epc {
@@ -100,6 +101,7 @@ struct pci_epc {
 	struct config_group		*group;
 	/* mutex to protect against concurrent access of EP controller */
 	struct mutex			lock;
+	unsigned long			function_num_map;
 	struct atomic_notifier_head	notifier;
 };
 
-- 
2.17.1