From patchwork Sun Jun 11 17:19:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Maciej W. Rozycki" X-Patchwork-Id: 13275297 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 70E5FF9EF for ; Sun, 11 Jun 2023 17:20:28 +0000 (UTC) Received: from angie.orcam.me.uk (angie.orcam.me.uk [IPv6:2001:4190:8020::34]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id EF8F810C4; Sun, 11 Jun 2023 10:20:04 -0700 (PDT) Received: by angie.orcam.me.uk (Postfix, from userid 500) id 53DBD9200C5; Sun, 11 Jun 2023 19:19:45 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id 4D8169200C1; Sun, 11 Jun 2023 18:19:45 +0100 (BST) Date: Sun, 11 Jun 2023 18:19:45 +0100 (BST) From: "Maciej W. Rozycki" To: Bjorn Helgaas , Mahesh J Salgaonkar , Oliver O'Halloran , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Saeed Mahameed , Leon Romanovsky , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni cc: Alex Williamson , Lukas Wunner , Mika Westerberg , Stefan Roese , Jim Wilson , David Abdurachmanov , =?utf-8?q?Pali_Roh?= =?utf-8?q?=C3=A1r?= , linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v9 08/14] PCI: Use distinct local vars in `pcie_retrain_link' In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_NONE, SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Use separate local variables to hold the respective values retrieved from the Link Control Register and the Link Status Register. Not only it improves readability, but it makes it possible for the compiler to detect actual uninitialised use should this code change in the future. Signed-off-by: Maciej W. Rozycki --- New change in v9. --- drivers/pci/pci.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) linux-pcie-retrain-link-lnkctl-lnksta.diff Index: linux-macro/drivers/pci/pci.c =================================================================== --- linux-macro.orig/drivers/pci/pci.c +++ linux-macro/drivers/pci/pci.c @@ -4922,30 +4922,31 @@ bool pcie_wait_for_link(struct pci_dev * bool pcie_retrain_link(struct pci_dev *pdev) { unsigned long end_jiffies; - u16 reg16; + u16 lnkctl; + u16 lnksta; - pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, ®16); - reg16 |= PCI_EXP_LNKCTL_RL; - pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, reg16); + pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnkctl); + lnkctl |= PCI_EXP_LNKCTL_RL; + pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnkctl); if (pdev->clear_retrain_link) { /* * Due to an erratum in some devices the Retrain Link bit * needs to be cleared again manually to allow the link * training to succeed. */ - reg16 &= ~PCI_EXP_LNKCTL_RL; - pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, reg16); + lnkctl &= ~PCI_EXP_LNKCTL_RL; + pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnkctl); } /* Wait for link training end. Break out after waiting for timeout. */ end_jiffies = jiffies + msecs_to_jiffies(PCIE_LINK_RETRAIN_TIMEOUT_MS); do { - pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, ®16); - if (!(reg16 & PCI_EXP_LNKSTA_LT)) + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnksta); + if (!(lnksta & PCI_EXP_LNKSTA_LT)) break; msleep(1); } while (time_before(jiffies, end_jiffies)); - return !(reg16 & PCI_EXP_LNKSTA_LT); + return !(lnksta & PCI_EXP_LNKSTA_LT); } /*