From patchwork Wed Sep 29 00:43:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Saheed O. 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Bolarinwa" To: helgaas@kernel.org Cc: "Bolarinwa O. Saheed" , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 1/4] PCI/ASPM: Remove struct pcie_link_state.parent Date: Wed, 29 Sep 2021 02:43:12 +0200 Message-Id: <20210929004315.22558-2-refactormyself@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210929004315.22558-1-refactormyself@gmail.com> References: <20210929004315.22558-1-refactormyself@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: "Bolarinwa O. Saheed" Information cached in struct pcie_link_state.parent is accessible via struct pci_dev. This patch: - removes *parent* from the *struct pcie_link_state* - creates pci_get_parent() which returns the parent of a pci_dev - replaces references to pcie_link_state.parent with a call to pci_get_parent() - removes BUG_ON(root->parent), instead uses the parent's root Signed-off-by: Bolarinwa O. Saheed --- drivers/pci/pcie/aspm.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 013a47f587ce..414c04ffe962 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -50,7 +50,6 @@ struct pcie_link_state { struct pci_dev *pdev; /* Upstream component of the Link */ struct pci_dev *downstream; /* Downstream component, function 0 */ struct pcie_link_state *root; /* pointer to the root port link */ - struct pcie_link_state *parent; /* pointer to the parent Link state */ struct list_head sibling; /* node in link_list */ /* ASPM state */ @@ -139,6 +138,14 @@ static int policy_to_clkpm_state(struct pcie_link_state *link) return 0; } +static struct pci_dev *pci_get_parent(struct pci_dev *pdev) +{ + if (!pdev || !pdev->bus->parent || !pdev->bus->parent->self) + return NULL; + + return pdev->bus->parent->self; +} + static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable) { struct pci_dev *child; @@ -379,6 +386,7 @@ static void encode_l12_threshold(u32 threshold_us, u32 *scale, u32 *value) static void pcie_aspm_check_latency(struct pci_dev *endpoint) { u32 latency, l1_switch_latency = 0; + struct pci_dev *parent; struct aspm_latency *acceptable; struct pcie_link_state *link; @@ -419,7 +427,8 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint) link->aspm_capable &= ~ASPM_STATE_L1; l1_switch_latency += 1000; - link = link->parent; + parent = pci_get_parent(link->pdev); + link = parent ? parent->link_state : NULL; } } @@ -793,9 +802,11 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state) static void pcie_config_aspm_path(struct pcie_link_state *link) { + struct pci_dev *parent; while (link) { pcie_config_aspm_link(link, policy_to_aspm_state(link)); - link = link->parent; + parent = pci_get_parent(link->pdev); + link = parent ? parent->link_state : NULL; } } @@ -864,16 +875,15 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev) !pdev->bus->parent->self) { link->root = link; } else { - struct pcie_link_state *parent; + struct pci_dev *parent; - parent = pdev->bus->parent->self->link_state; - if (!parent) { + parent = pci_get_parent(pdev); + if (!parent->link_state) { kfree(link); return NULL; } - link->parent = parent; - link->root = link->parent->root; + link->root = parent->link_state->root; } list_add(&link->sibling, &link_list); @@ -962,7 +972,11 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) static void pcie_update_aspm_capable(struct pcie_link_state *root) { struct pcie_link_state *link; - BUG_ON(root->parent); + struct pci_dev *parent = pci_get_parent(root->pdev); + + if (parent && parent->link_state) + root = parent->link_state->root; + list_for_each_entry(link, &link_list, sibling) { if (link->root != root) continue; @@ -985,6 +999,7 @@ static void pcie_update_aspm_capable(struct pcie_link_state *root) /* @pdev: the endpoint device */ void pcie_aspm_exit_link_state(struct pci_dev *pdev) { + struct pci_dev *parent_dev; struct pci_dev *parent = pdev->bus->self; struct pcie_link_state *link, *root, *parent_link; @@ -1002,7 +1017,8 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev) link = parent->link_state; root = link->root; - parent_link = link->parent; + parent_dev = pci_get_parent(link->pdev); + parent_link = parent_dev ? parent_dev->link_state : NULL; /* All functions are removed, so just disable ASPM for the link */ pcie_config_aspm_link(link, 0);