From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr2-f35.google.com (mail-wr2-f35.google.com [74.125.225.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC5FB3B27DF for ; Sun, 27 Sep 2026 17:52:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.225.99 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790531536; cv=none; b=Tjz5wsV/+QHsN2nfpfXo+08t5CkB+vv0178eWLh3TfJnLjA9hkTLg5xvlU3xbGLGpDoz5AMkvAkn1kJjNh6iZK0ZzuV/HamTFVK/e8Wm/wUIky9FJDGPnJvQavcCJEjoLa/+oputXBqAwgBclYAUBDtldIKfPPtFBvqfSGqXEH8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790531536; c=relaxed/simple; bh=XSQC/81m+2NGyN2HF+46o8gTXzhtxgDYUbfAyk7YscA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NjKHc8eK73cNssXLNOP42bsiAEM2HTK4JA3siRCeIq+3kUq2tP1KNef1GJq+kQh8x/I/hCwvCV+5hLAW23MhtlGAzbee+ON6hkusA8jHzztbzWrf/g8iait3MjXKv+dhRvmnkPNRx1FZxfKKa+dNn6jddCdTSARfne/TrsRaEjQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=C0bhMz9H; arc=none smtp.client-ip=74.125.225.99 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="C0bhMz9H" Received: by mail-wr2-f35.google.com with SMTP id ffacd0b85a97d-4887f6cf16bso1354167f8f.0 for ; Sun, 27 Sep 2026 10:52:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1790531533; x=1791136333; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=/YmLfvNYngEdzxR1cneHvQxjYljmSjSjM29lfe3X1Ew=; b=C0bhMz9HjNzjPLDdYarMqRhGc6e0crr4KxNWG89p9AbkVW9F698rVzImgG1L3cJ2je ucIwZApj//5n39lwrk2N35hSEkUuTgjWv+QWb0C2ueFmqoNMf+UCRU5kpTLCvu416WOu ufwJpgoTsX5BW+LAmignUNJWSG267ygsgmfC5VAUNv2FIRYIHl9Ckibef5cOcLhCvAKK NHivJi2qCO4Y54V5uWBhHQhBbAgzvfatoDYs9TlMyEM/3a5IryS/BSE6bYNweMdYVFJn OTMrwJNazIj5lK7OC7tIKnR6l8j9tKA4PL3PLMJOUuBJz2GKh1Pim8Ff4kSGYQfLbYuY WgZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790531533; x=1791136333; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=/YmLfvNYngEdzxR1cneHvQxjYljmSjSjM29lfe3X1Ew=; b=Xa72QoEbKos+H9pB1BpPpassAFZCc7XdnPULEwG9GkpLP3OGAYJ/cZ+Q1AsbAUeX76 x7HrUFX00KECoyT7zVkkop3SWsjW9XqYg6eKyAz6J2LOxx3Bq5Zfs361vKgo13oYa1ZQ emfHTsL7nR2GnTLFYBw47r3NcZGslR1FkNMjSXRShLuwFvkProorawZbQYdXsW/8MAhw VsQH83CeK7Ra1ROWtSfiHN0dt+DpyyuG/ZumHWQFyThY3lkoQPG4auJSyf7OMVGjXMWm JnRUsNUHa5x9wfdcIIq8usQDILc+JJJEOeOYPUHY3JLaK542VHTNyz7YCDw2wqevzilt RCqQ== X-Forwarded-Encrypted: i=1; AKwUvBz7iPtwDT+Rt4f5BbKPYx4DKV4tDIlOnPReH0mDCKVc4DZeNiVZs0FZopS6841uFJmMXEaI+0Lk29/Ey3M=@vger.kernel.org X-Gm-Message-State: AFq9FYKhHmiu2/lr3seakJpzty1LBPzlvpU7raMm8kCVaGgFZabO1ZLw 0SbgPDJgn93fjDjJubJgqvjDeYsNwnJMtgyYSjNiBSRGqIMS5T3kw/jj X-Gm-Gg: AYBFou1KSBbKT6etztFopZycguPoauXTu+RMq7lFwbbeWv2kMXOyhxPVgzPk3+6NaMB rRN2AbanfsE3yW2QJrnNInb37X/OchHed2hsMF6dPi/Ybc6gYsEiSaKvRsSJcOaCAlm5DrByOR2 XSnMv62WXDHn3IYxqhu2N8gb3dl6ka37sitTHD0/cBonCVnrSNyAo3UMNh9pBntrrGdoKs/sIqo XHUAMdw9Y1L2Udcl5/nD2G229XVrOGYQFyJjSaVUF+W3J59+UzoRfAvu3f/N7loAVWTkiHn7fTL 4HtJeQIqBlSJ5xz7ZkZWhJH0KzEpEJbEzXTEQsuLLVX3hTHUJfjvr+KG3M4Sp5exbj6mvydvNZc o1LunErshmrFPhg4/8UymEHbbcIceQ87evRN54Ooorw9cFmGUiXfvWyA8q7ZmbzJnv6cDciMRAh pxd2e/zQhhjH24104oWu2HiAgDsUtUu+/M5HHHz1ajKJDxyeKkcAu4tqKzd77YXM6JAKFjedkOo t5fAo2Xv0ftAToeK4cWdoXQOCoVfRi8X4g72Et6yZWEEv3pxbZrIX+Xz7T++oNEda8= X-Received: by 2002:a05:6000:2010:b0:488:7803:c1ef with SMTP id ffacd0b85a97d-4887db496acmr14370762f8f.48.1790531532912; Sun, 27 Sep 2026 10:52:12 -0700 (PDT) Received: from f3a6eae2255e.fritz.box (dynamic-002-214-014-217.2.214.pool.telefonica.de. [2.214.14.217]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4887a30bcc4sm22563923f8f.1.2026.09.27.10.52.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 27 Sep 2026 10:52:12 -0700 (PDT) From: Abhin Parekadan Jose To: Bjorn Helgaas , Lukas Wunner , "Michael S. Tsirkin" Cc: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Shuai Xue , Kees Cook , Mahesh J Salgaonkar , Oliver O'Halloran , linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Abhin Parekadan Jose Subject: [PATCH RFC v3 3/5] PCI/DPC: Add pci_dpc_wait_recovery() Date: Sun, 27 Sep 2026 17:52:00 +0000 Message-ID: <20260927175203.928270-4-abhinjoses@gmail.com> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20260927175203.928270-1-abhinjoses@gmail.com> References: <20260927175203.928270-1-abhinjoses@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit pci_dpc_recovered() awaits completion of DPC recovery and then tells whether DPC recovered successfully, using test_and_clear_bit() on PCI_DPC_RECOVERED. The answer is one-shot: only the first caller sees true. Split pci_dpc_recovered() into: - pci_dpc_hp_sync_supported(), the check whether hotplug can synchronize with DPC at all. - dpc_wait_completed(), the wait for recovery with its 4 second timeout; - the final test_and_clear_bit(). Add pci_dpc_wait_recovery(), which does the check and the wait but leaves PCI_DPC_RECOVERED alone. No functional change intended. Signed-off-by: Abhin Parekadan Jose Assisted-by: LLM --- drivers/pci/pci.h | 2 ++ drivers/pci/pcie/dpc.c | 54 ++++++++++++++++++++++++++++++++---------- 2 files changed, 44 insertions(+), 12 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index cfa0202bf610b..b1d9df904c625 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -941,12 +941,14 @@ void pci_restore_dpc_state(struct pci_dev *dev); void pci_dpc_init(struct pci_dev *pdev); void dpc_process_error(struct pci_dev *pdev); pci_ers_result_t dpc_reset_link(struct pci_dev *pdev); +void pci_dpc_wait_recovery(struct pci_dev *pdev); bool pci_dpc_recovered(struct pci_dev *pdev); unsigned int dpc_tlp_log_len(struct pci_dev *dev); #else static inline void pci_save_dpc_state(struct pci_dev *dev) { } static inline void pci_restore_dpc_state(struct pci_dev *dev) { } static inline void pci_dpc_init(struct pci_dev *pdev) { } +static inline void pci_dpc_wait_recovery(struct pci_dev *pdev) { } static inline bool pci_dpc_recovered(struct pci_dev *pdev) { return false; } #endif diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c index 2b779bd1d861b..a6438a7e3d9c7 100644 --- a/drivers/pci/pcie/dpc.c +++ b/drivers/pci/pcie/dpc.c @@ -92,15 +92,7 @@ static bool dpc_completed(struct pci_dev *pdev) return true; } -/** - * pci_dpc_recovered - whether DPC triggered and has recovered successfully - * @pdev: PCI device - * - * Return true if DPC was triggered for @pdev and has recovered successfully. - * Wait for recovery if it hasn't completed yet. Called from the PCIe hotplug - * driver to recognize and ignore Link Down/Up events caused by DPC. - */ -bool pci_dpc_recovered(struct pci_dev *pdev) +static bool pci_dpc_hp_sync_supported(struct pci_dev *pdev) { struct pci_host_bridge *host; @@ -108,13 +100,18 @@ bool pci_dpc_recovered(struct pci_dev *pdev) return false; /* - * Synchronization between hotplug and DPC is not supported - * if DPC is owned by firmware and EDR is not enabled. - */ + * Synchronization between hotplug and DPC is only supported if DPC is owned + * by the OS, or by firmware with EDR enabled. + */ host = pci_find_host_bridge(pdev->bus); if (!host->native_dpc && !IS_ENABLED(CONFIG_PCIE_EDR)) return false; + return true; +} + +static void dpc_wait_completed(struct pci_dev *pdev) +{ /* * Need a timeout in case DPC never completes due to failure of * dpc_wait_rp_inactive(). The spec doesn't mandate a time limit, @@ -122,6 +119,39 @@ bool pci_dpc_recovered(struct pci_dev *pdev) */ wait_event_timeout(dpc_completed_waitqueue, dpc_completed(pdev), msecs_to_jiffies(4000)); +} + +/** + * pci_dpc_wait_recovery - await completion of DPC recovery + * @pdev: PCI device + * + * Wait for recovery if DPC was triggered for @pdev and recovery hasn't + * completed yet. Unlike pci_dpc_recovered(), leave the record of a + * successful recovery in place. Called from the PCIe hotplug driver where + * it needs the link to have settled, but not the cause of a link change. + * Nothing is awaited if synchronization between hotplug and DPC is not + * supported for @pdev. + */ +void pci_dpc_wait_recovery(struct pci_dev *pdev) +{ + if (pci_dpc_hp_sync_supported(pdev)) + dpc_wait_completed(pdev); +} + +/** + * pci_dpc_recovered - whether DPC triggered and has recovered successfully + * @pdev: PCI device + * + * Return true if DPC was triggered for @pdev and has recovered successfully. + * Wait for recovery if it hasn't completed yet. Called from the PCIe hotplug + * driver to recognize and ignore Link Down/Up events caused by DPC. + */ +bool pci_dpc_recovered(struct pci_dev *pdev) +{ + if (!pci_dpc_hp_sync_supported(pdev)) + return false; + + dpc_wait_completed(pdev); return test_and_clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags); } -- 2.51.1