linux-kernel - [PATCH v2 1/2] PCI: plda: Remove unused IRQ handler and simplify IRQ request logic

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Message-ID: <20250316171250.5901-1-linux.amoon@gmail.com>
Date: Sun, 16 Mar 2025 22:42:45 +0530
From: Anand Moon <linux.amoon@...il.com>
To: Daire McNamara <daire.mcnamara@...rochip.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Rob Herring <robh@...nel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Kevin Xie <kevin.xie@...rfivetech.com>,
	Minda Chen <minda.chen@...rfivetech.com>,
	Conor Dooley <conor.dooley@...rochip.com>,
	Mason Huo <mason.huo@...rfivetech.com>,
	linux-pci@...r.kernel.org (open list:PCI DRIVER FOR PLDA PCIE IP),
	linux-kernel@...r.kernel.org (open list)
Cc: Anand Moon <linux.amoon@...il.com>
Subject: [PATCH v2 1/2] PCI: plda: Remove unused IRQ handler and simplify IRQ request logic

The plda_event_handler() function has been removed since it only returned
IRQ_HANDLED without performing any processing. Additionally, the IRQ
request logic in plda_init_interrupts() has been streamlined by removing
the redundant devm_request_irq() call when the request_event_irq()
callback is not defined.

Change ensures that interrupts are requested exclusively through the
request_event_irq() callback when available, enhancing code clarity
and maintainability.

Changes help fix kmemleak reported following debug log.

$ sudo cat /sys/kernel/debug/kmemleak
unreferenced object 0xffffffd6c47c2600 (size 128):
  comm "kworker/u16:2", pid 38, jiffies 4294942263
  hex dump (first 32 bytes):
    cc 7c 5a 8d ff ff ff ff 40 b0 47 c8 d6 ff ff ff  .|Z.....@.......
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 4f07ff07):
    __create_object+0x2a/0xfc
    kmemleak_alloc+0x38/0x98
    __kmalloc_cache_noprof+0x296/0x444
    request_threaded_irq+0x168/0x284
    devm_request_threaded_irq+0xa8/0x13c
    plda_init_interrupts+0x46e/0x858
    plda_pcie_host_init+0x356/0x468
    starfive_pcie_probe+0x2f6/0x398
    platform_probe+0x106/0x150
    really_probe+0x30e/0x746
    __driver_probe_device+0x11c/0x2c2
    driver_probe_device+0x5e/0x316
    __device_attach_driver+0x296/0x3a4
    bus_for_each_drv+0x1d0/0x260
    __device_attach+0x1fa/0x2d6
    device_initial_probe+0x14/0x28
unreferenced object 0xffffffd6c47c2900 (size 128):
  comm "kworker/u16:2", pid 38, jiffies 4294942281

Fixes: 4602c370bdf6 ("PCI: microchip: Move IRQ functions to pcie-plda-host.c")
Cc: Minda Chen <minda.chen@...rfivetech.com>
Signed-off-by: Anand Moon <linux.amoon@...il.com>
---
v1: drop the dummy IRQ handler used in previous version
   [0] https://lore.kernel.org/linux-pci/20250224144155.omzrmls7hpjqw6yl@thinkpad/T/
---
 drivers/pci/controller/plda/pcie-plda-host.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/controller/plda/pcie-plda-host.c b/drivers/pci/controller/plda/pcie-plda-host.c
index 4153214ca4103..f7edfa97723f8 100644
--- a/drivers/pci/controller/plda/pcie-plda-host.c
+++ b/drivers/pci/controller/plda/pcie-plda-host.c
@@ -280,11 +280,6 @@ static u32 plda_get_events(struct plda_pcie_rp *port)
 	return events;
 }
 
-static irqreturn_t plda_event_handler(int irq, void *dev_id)
-{
-	return IRQ_HANDLED;
-}
-
 static void plda_handle_event(struct irq_desc *desc)
 {
 	struct plda_pcie_rp *port = irq_desc_get_handler_data(desc);
@@ -452,16 +447,13 @@ int plda_init_interrupts(struct platform_device *pdev,
 			return -ENXIO;
 		}
 
-		if (event->request_event_irq)
+		if (event->request_event_irq) {
 			ret = event->request_event_irq(port, event_irq, i);
-		else
-			ret = devm_request_irq(dev, event_irq,
-					       plda_event_handler,
-					       0, NULL, port);
-
-		if (ret) {
-			dev_err(dev, "failed to request IRQ %d\n", event_irq);
-			return ret;
+			if (ret) {
+				dev_err(dev, "failed to request IRQ %d\n",
+					event_irq);
+				return ret;
+			}
 		}
 	}
 

base-commit: cb82ca153949c6204af793de24b18a04236e79fd
-- 
2.48.1