linux-kernel - [PATCH v1] powerpc/pci: restore LSI mappings on card present state change

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Message-Id: <20240827165738.1083422-1-oocheret@cisco.com>
Date: Tue, 27 Aug 2024 09:57:35 -0700
From: Oleksandr Ocheretnyi <oocheret@...co.com>
To: xe-linux-external@...co.com, Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Naveen N Rao <naveen@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Sam Ravnborg <sam@...nborg.org>,
        Oleksandr Ocheretnyi <oocheret@...co.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1] powerpc/pci: restore LSI mappings on card present state change

Commit 450be4960a0f ("powerpc/pci: Remove LSI mappings on device
teardown") frees irq descriptors on PCIe hotplug link change event
(Link Down), but the disposed mappings are not restored back on PCIe
hotplug link change event (Card present).

This change restores IRQ mappings disposed earlier when pcieport
link's gone down. So, the call pci_read_irq_line is invoked again
on pcieport's state change (Card present).

Fixes 450be4960a0f ("powerpc/pci: Remove LSI mappings on device teardown")
Signed-off-by: Oleksandr Ocheretnyi <oocheret@...co.com>
---
 arch/powerpc/kernel/pci-common.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index eac84d687b53..a0e7cab2baa7 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -390,22 +390,32 @@ static void ppc_pci_intx_release(struct kref *kref)
 	kfree(vi);
 }
 
+static int pci_read_irq_line(struct pci_dev *pci_dev);
+
 static int ppc_pci_unmap_irq_line(struct notifier_block *nb,
 			       unsigned long action, void *data)
 {
 	struct pci_dev *pdev = to_pci_dev(data);
 
-	if (action == BUS_NOTIFY_DEL_DEVICE) {
-		struct pci_intx_virq *vi;
-
-		mutex_lock(&intx_mutex);
-		list_for_each_entry(vi, &intx_list, list_node) {
-			if (vi->virq == pdev->irq) {
-				kref_put(&vi->kref, ppc_pci_intx_release);
-				break;
+	switch (action) {
+		case BUS_NOTIFY_DEL_DEVICE:
+			{
+				struct pci_intx_virq *vi;
+
+				mutex_lock(&intx_mutex);
+				list_for_each_entry(vi, &intx_list, list_node) {
+					if (vi->virq == pdev->irq) {
+						kref_put(&vi->kref, ppc_pci_intx_release);
+						break;
+					}
+				}
+				mutex_unlock(&intx_mutex);
 			}
-		}
-		mutex_unlock(&intx_mutex);
+			break;
+
+		case BUS_NOTIFY_ADD_DEVICE:
+			pci_read_irq_line(pdev);
+			break;
 	}
 
 	return NOTIFY_DONE;
-- 
2.39.3