linux-kernel - [RFC PATCH v2 3/4] PCI/ASPM: Remove struct pcie_link

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Date:   Wed, 29 Sep 2021 02:43:14 +0200
From:   "Saheed O. Bolarinwa" <refactormyself@...il.com>
To:     helgaas@...nel.org
Cc:     "Bolarinwa O. Saheed" <refactormyself@...il.com>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH v2 3/4] PCI/ASPM: Remove struct pcie_link_state.downstream

From: "Bolarinwa O. Saheed" <refactormyself@...il.com>

Information on the downstream component is cached in
struct pcie_link_state.downstream it obtained within
alloc_pcie_link_state() by calling pci_function_0()

This patch:
 - removes *downstream* from *struct pcie_link_state*.
 - replaces references to pcie_link_state.downstream with
   a call to pci_function_0(pdev->subordinate).

Signed-off-by: Bolarinwa O. Saheed <refactormyself@...il.com>
---
 drivers/pci/pcie/aspm.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index ad78aaeea444..56d4fe7d50b5 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -48,7 +48,6 @@ struct aspm_latency {
 
 struct pcie_link_state {
 	struct pci_dev *pdev;		/* Upstream component of the Link */
-	struct pci_dev *downstream;	/* Downstream component, function 0 */
 	struct list_head sibling;	/* node in link_list */
 
 	/* ASPM state */
@@ -460,7 +459,8 @@ static void pci_clear_and_set_dword(struct pci_dev *pdev, int pos,
 static void aspm_calc_l1ss_info(struct pcie_link_state *link,
 				u32 parent_l1ss_cap, u32 child_l1ss_cap)
 {
-	struct pci_dev *child = link->downstream, *parent = link->pdev;
+	struct pci_dev *parent = link->pdev;
+	struct pci_dev *child = pci_function_0(link->pdev->subordinate);
 	u32 val1, val2, scale1, scale2;
 	u32 t_common_mode, t_power_on, l1_2_threshold, scale, value;
 	u32 ctl1 = 0, ctl2 = 0;
@@ -550,7 +550,8 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
 
 static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
 {
-	struct pci_dev *child = link->downstream, *parent = link->pdev;
+	struct pci_dev *parent = link->pdev;
+	struct pci_dev *child = pci_function_0(link->pdev->subordinate);
 	u32 parent_lnkcap, child_lnkcap;
 	u16 parent_lnkctl, child_lnkctl;
 	u32 parent_l1ss_cap, child_l1ss_cap;
@@ -692,7 +693,8 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
 static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
 {
 	u32 val, enable_req;
-	struct pci_dev *child = link->downstream, *parent = link->pdev;
+	struct pci_dev *parent = link->pdev;
+	struct pci_dev *child = pci_function_0(link->pdev->subordinate);
 
 	enable_req = (link->aspm_enabled ^ state) & state;
 
@@ -751,7 +753,8 @@ static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
 static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
 {
 	u32 upstream = 0, dwstream = 0;
-	struct pci_dev *child = link->downstream, *parent = link->pdev;
+	struct pci_dev *parent = link->pdev;
+	struct pci_dev *child = pci_function_0(link->pdev->subordinate);
 	struct pci_bus *linkbus = parent->subordinate;
 
 	/* Enable only the states that were not explicitly disabled */
@@ -879,7 +882,6 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
 
 	INIT_LIST_HEAD(&link->sibling);
 	link->pdev = pdev;
-	link->downstream = pci_function_0(pdev->subordinate);
 
 	list_add(&link->sibling, &link_list);
 	pdev->link_state = link;
-- 
2.20.1