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* [PATCH RFC] PCI: Convert devm_pci_alloc_host_bridge() users to error-pointer returns
@ 2025-09-21 16:14 Alok Tiwari
  2025-09-21 17:19 ` Marc Zyngier
  2025-09-22 10:55 ` AngeloGioacchino Del Regno
  0 siblings, 2 replies; 3+ messages in thread
From: Alok Tiwari @ 2025-09-21 16:14 UTC (permalink / raw)
  To: thomas.petazzoni, pali, lpieralisi, kwilczynski, mani, robh,
	bhelgaas, joyce.ooi, alyssa, maz, jim2101024, florian.fainelli,
	bcm-kernel-feedback-list, rjui, sbranden, ryder.lee, jianjun.wang,
	sergio.paracuellos, matthias.bgg, angelogioacchino.delregno,
	marek.vasut+renesas, yoshihiro.shimoda.uh, geert+renesas,
	magnus.damm, shawn.lin, heiko, michal.simek, bharat.kumar.gogada,
	will, kys, haiyangz, wei.liu, decui, linus.walleij,
	thierry.reding, jonathanh, rric, nirmal.patel, toan,
	jonathan.derrick, linux-pci
  Cc: alok.a.tiwari, linux-arm-kernel, linux-kernel, linux-rpi-kernel,
	linux-mediatek, linux-renesas-soc, linux-rockchip, linux-hyperv,
	linux-tegra

devm_pci_alloc_host_bridge() and pci_alloc_host_bridge() previously
returned NULL on failure, forcing callers to special-case NULL handling
and often hardcode -ENOMEM as the error.

This series updates devm_pci_alloc_host_bridge() to consistently return
error pointers (ERR_PTR) with the actual error code, instead of NULL.
All callers across PCI host controller drivers are updated to use
IS_ERR_OR_NULL()/PTR_ERR() instead of NULL checks and hardcoded -ENOMEM.

Benefits:
  - Standardizes error handling with Linux kernel ERR_PTR()/PTR_ERR()
    conventions.
  - Ensures that the actual error code from lower-level helpers is
    propagated back to the caller.
  - Removes ambiguity between NULL and error pointer returns.

Touched drivers include:
 cadence (J721E, cadence-plat)
 dwc (designware, qcom)
 mobiveil (layerscape-gen4, mobiveil-plat)
 aardvark, ftpci100, ixp4xx, loongson, mvebu, rcar, tegra, v3-semi,
 versatile, xgene, altera, brcmstb, iproc, mediatek, mt7621, xilinx,
 plda, and others

This patch updates error handling across these host controller drivers
 so that callers consistently receive ERR_PTR() instead of NULL.

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
---
 arch/mips/pci/pci-xtalk-bridge.c                       | 4 ++--
 drivers/pci/controller/cadence/pci-j721e.c             | 4 ++--
 drivers/pci/controller/cadence/pcie-cadence-plat.c     | 4 ++--
 drivers/pci/controller/dwc/pcie-designware-host.c      | 4 ++--
 drivers/pci/controller/dwc/pcie-qcom.c                 | 4 ++--
 drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c | 4 ++--
 drivers/pci/controller/mobiveil/pcie-mobiveil-plat.c   | 4 ++--
 drivers/pci/controller/pci-aardvark.c                  | 4 ++--
 drivers/pci/controller/pci-ftpci100.c                  | 4 ++--
 drivers/pci/controller/pci-host-common.c               | 4 ++--
 drivers/pci/controller/pci-hyperv.c                    | 4 ++--
 drivers/pci/controller/pci-ixp4xx.c                    | 4 ++--
 drivers/pci/controller/pci-loongson.c                  | 4 ++--
 drivers/pci/controller/pci-mvebu.c                     | 4 ++--
 drivers/pci/controller/pci-rcar-gen2.c                 | 4 ++--
 drivers/pci/controller/pci-tegra.c                     | 4 ++--
 drivers/pci/controller/pci-v3-semi.c                   | 4 ++--
 drivers/pci/controller/pci-versatile.c                 | 4 ++--
 drivers/pci/controller/pci-xgene.c                     | 4 ++--
 drivers/pci/controller/pcie-altera.c                   | 4 ++--
 drivers/pci/controller/pcie-brcmstb.c                  | 4 ++--
 drivers/pci/controller/pcie-iproc-bcma.c               | 4 ++--
 drivers/pci/controller/pcie-iproc-platform.c           | 4 ++--
 drivers/pci/controller/pcie-mediatek-gen3.c            | 4 ++--
 drivers/pci/controller/pcie-mediatek.c                 | 4 ++--
 drivers/pci/controller/pcie-mt7621.c                   | 4 ++--
 drivers/pci/controller/pcie-rcar-host.c                | 4 ++--
 drivers/pci/controller/pcie-rockchip-host.c            | 4 ++--
 drivers/pci/controller/pcie-xilinx-cpm.c               | 4 ++--
 drivers/pci/controller/pcie-xilinx-dma-pl.c            | 4 ++--
 drivers/pci/controller/pcie-xilinx-nwl.c               | 4 ++--
 drivers/pci/controller/pcie-xilinx.c                   | 4 ++--
 drivers/pci/controller/plda/pcie-plda-host.c           | 4 ++--
 drivers/pci/probe.c                                    | 8 ++++----
 34 files changed, 70 insertions(+), 70 deletions(-)

diff --git a/arch/mips/pci/pci-xtalk-bridge.c b/arch/mips/pci/pci-xtalk-bridge.c
index e00c38620d14..c2c8ed8ecac1 100644
--- a/arch/mips/pci/pci-xtalk-bridge.c
+++ b/arch/mips/pci/pci-xtalk-bridge.c
@@ -636,8 +636,8 @@ static int bridge_probe(struct platform_device *pdev)
 	pci_set_flags(PCI_PROBE_ONLY);
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*bc));
-	if (!host) {
-		err = -ENOMEM;
+	if (IS_ERR_OR_NULL(host)) {
+		err = PTR_ERR(host);
 		goto err_remove_domain;
 	}
 
diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
index 6c93f39d0288..3b8afaef21a6 100644
--- a/drivers/pci/controller/cadence/pci-j721e.c
+++ b/drivers/pci/controller/cadence/pci-j721e.c
@@ -475,8 +475,8 @@ static int j721e_pcie_probe(struct platform_device *pdev)
 			return -ENODEV;
 
 		bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
-		if (!bridge)
-			return -ENOMEM;
+		if (IS_ERR_OR_NULL(bridge))
+			return PTR_ERR(bridge);
 
 		if (!data->byte_access_allowed)
 			bridge->ops = &cdns_ti_pcie_host_ops;
diff --git a/drivers/pci/controller/cadence/pcie-cadence-plat.c b/drivers/pci/controller/cadence/pcie-cadence-plat.c
index 0456845dabb9..7570cb5998f6 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-plat.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-plat.c
@@ -66,8 +66,8 @@ static int cdns_plat_pcie_probe(struct platform_device *pdev)
 			return -ENODEV;
 
 		bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
-		if (!bridge)
-			return -ENOMEM;
+		if (IS_ERR_OR_NULL(bridge))
+			return PTR_ERR(bridge);
 
 		rc = pci_host_bridge_priv(bridge);
 		rc->pcie.dev = dev;
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 952f8594b501..b2b99f275c19 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -467,8 +467,8 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 	raw_spin_lock_init(&pp->lock);
 
 	bridge = devm_pci_alloc_host_bridge(dev, 0);
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pp->bridge = bridge;
 
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 294babe1816e..34d35c925c62 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1809,8 +1809,8 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 		struct pci_config_window *cfg;
 
 		bridge = devm_pci_alloc_host_bridge(dev, 0);
-		if (!bridge) {
-			ret = -ENOMEM;
+		if (IS_ERR_OR_NULL(bridge)) {
+			ret = PTR_ERR(bridge);
 			goto err_pm_runtime_put;
 		}
 
diff --git a/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c b/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
index 4919b27eaf44..f9ebefc71be3 100644
--- a/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
+++ b/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
@@ -207,8 +207,8 @@ static int __init ls_g4_pcie_probe(struct platform_device *pdev)
 	}
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	mv_pci = &pcie->pci;
diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil-plat.c b/drivers/pci/controller/mobiveil/pcie-mobiveil-plat.c
index c5bb87ff6d9a..9d2e3b0bc866 100644
--- a/drivers/pci/controller/mobiveil/pcie-mobiveil-plat.c
+++ b/drivers/pci/controller/mobiveil/pcie-mobiveil-plat.c
@@ -27,8 +27,8 @@ static int mobiveil_pcie_probe(struct platform_device *pdev)
 
 	/* allocate the PCIe port */
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	pcie->rp.bridge = bridge;
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index e34bea1ff0ac..4b75a451efe4 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1740,8 +1740,8 @@ static int advk_pcie_probe(struct platform_device *pdev)
 	int ret, irq;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(struct advk_pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	pcie->pdev = pdev;
diff --git a/drivers/pci/controller/pci-ftpci100.c b/drivers/pci/controller/pci-ftpci100.c
index 28e43831c0f1..0618d70fbdda 100644
--- a/drivers/pci/controller/pci-ftpci100.c
+++ b/drivers/pci/controller/pci-ftpci100.c
@@ -419,8 +419,8 @@ static int faraday_pci_probe(struct platform_device *pdev)
 	u32 val;
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*p));
-	if (!host)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	host->ops = &faraday_pci_ops;
 	p = pci_host_bridge_priv(host);
diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index 810d1c8de24e..28c5d55062ed 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -60,8 +60,8 @@ int pci_host_common_init(struct platform_device *pdev,
 	struct pci_config_window *cfg;
 
 	bridge = devm_pci_alloc_host_bridge(dev, 0);
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	of_pci_check_probe_only();
 
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index d2b7e8ea710b..0b88e396c323 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -3759,8 +3759,8 @@ static int hv_pci_probe(struct hv_device *hdev,
 	int ret;
 
 	bridge = devm_pci_alloc_host_bridge(&hdev->device, 0);
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
 	if (!hbus)
diff --git a/drivers/pci/controller/pci-ixp4xx.c b/drivers/pci/controller/pci-ixp4xx.c
index acb85e0d5675..422ec30757ee 100644
--- a/drivers/pci/controller/pci-ixp4xx.c
+++ b/drivers/pci/controller/pci-ixp4xx.c
@@ -528,8 +528,8 @@ static int __init ixp4xx_pci_probe(struct platform_device *pdev)
 	int i;
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*p));
-	if (!host)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	host->ops = &ixp4xx_pci_ops;
 	p = pci_host_bridge_priv(host);
diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index bc630ab8a283..b832d79faf52 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -326,8 +326,8 @@ static int loongson_pci_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*priv));
-	if (!bridge)
-		return -ENODEV;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	priv = pci_host_bridge_priv(bridge);
 	priv->pdev = pdev;
diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
index a72aa57591c0..c0fd8efaf540 100644
--- a/drivers/pci/controller/pci-mvebu.c
+++ b/drivers/pci/controller/pci-mvebu.c
@@ -1456,8 +1456,8 @@ static int mvebu_pcie_probe(struct platform_device *pdev)
 	int num, i, ret;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(struct mvebu_pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	pcie->pdev = pdev;
diff --git a/drivers/pci/controller/pci-rcar-gen2.c b/drivers/pci/controller/pci-rcar-gen2.c
index d29866485361..845347e0317e 100644
--- a/drivers/pci/controller/pci-rcar-gen2.c
+++ b/drivers/pci/controller/pci-rcar-gen2.c
@@ -284,8 +284,8 @@ static int rcar_pci_probe(struct platform_device *pdev)
 	void __iomem *reg;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*priv));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	priv = pci_host_bridge_priv(bridge);
 	bridge->sysdata = priv;
diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index 467ddc701adc..dc45692e9906 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -2568,8 +2568,8 @@ static int tegra_pcie_probe(struct platform_device *pdev)
 	int err;
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!host)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(host);
 	host->sysdata = pcie;
diff --git a/drivers/pci/controller/pci-v3-semi.c b/drivers/pci/controller/pci-v3-semi.c
index 460a825325dd..6f1f82e4228d 100644
--- a/drivers/pci/controller/pci-v3-semi.c
+++ b/drivers/pci/controller/pci-v3-semi.c
@@ -715,8 +715,8 @@ static int v3_pci_probe(struct platform_device *pdev)
 	int ret;
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*v3));
-	if (!host)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	host->ops = &v3_pci_ops;
 	v3 = pci_host_bridge_priv(host);
diff --git a/drivers/pci/controller/pci-versatile.c b/drivers/pci/controller/pci-versatile.c
index e9a6758fe2c1..b367c17db667 100644
--- a/drivers/pci/controller/pci-versatile.c
+++ b/drivers/pci/controller/pci-versatile.c
@@ -72,8 +72,8 @@ static int versatile_pci_probe(struct platform_device *pdev)
 	struct pci_host_bridge *bridge;
 
 	bridge = devm_pci_alloc_host_bridge(dev, 0);
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	versatile_pci_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(versatile_pci_base))
diff --git a/drivers/pci/controller/pci-xgene.c b/drivers/pci/controller/pci-xgene.c
index b95afa35201d..3b3a6e08d17b 100644
--- a/drivers/pci/controller/pci-xgene.c
+++ b/drivers/pci/controller/pci-xgene.c
@@ -622,8 +622,8 @@ static int xgene_pcie_probe(struct platform_device *pdev)
 				     "MSI driver not ready\n");
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*port));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	port = pci_host_bridge_priv(bridge);
 
diff --git a/drivers/pci/controller/pcie-altera.c b/drivers/pci/controller/pcie-altera.c
index 3dbb7adc421c..92f976bea8ef 100644
--- a/drivers/pci/controller/pcie-altera.c
+++ b/drivers/pci/controller/pcie-altera.c
@@ -995,8 +995,8 @@ static int altera_pcie_probe(struct platform_device *pdev)
 	const struct altera_pcie_data *data;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	pcie->pdev = pdev;
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 9afbd02ded35..c683418c176c 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -1874,8 +1874,8 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 	int ret;
 
 	bridge = devm_pci_alloc_host_bridge(&pdev->dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	data = of_device_get_match_data(&pdev->dev);
 	if (!data) {
diff --git a/drivers/pci/controller/pcie-iproc-bcma.c b/drivers/pci/controller/pcie-iproc-bcma.c
index 99a99900444d..d2adc4162a6c 100644
--- a/drivers/pci/controller/pcie-iproc-bcma.c
+++ b/drivers/pci/controller/pcie-iproc-bcma.c
@@ -39,8 +39,8 @@ static int iproc_bcma_pcie_probe(struct bcma_device *bdev)
 	int ret;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 
diff --git a/drivers/pci/controller/pcie-iproc-platform.c b/drivers/pci/controller/pcie-iproc-platform.c
index 0cb78c583c7e..8f6843ce573e 100644
--- a/drivers/pci/controller/pcie-iproc-platform.c
+++ b/drivers/pci/controller/pcie-iproc-platform.c
@@ -46,8 +46,8 @@ static int iproc_pltfm_pcie_probe(struct platform_device *pdev)
 	int ret;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 
diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index 97147f43e41c..e3e908236238 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -1175,8 +1175,8 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 	int err;
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!host)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(host);
 
diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index 24cc30a2ab6c..7a2c74996ace 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -1083,8 +1083,8 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 	int err;
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!host)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(host);
 
diff --git a/drivers/pci/controller/pcie-mt7621.c b/drivers/pci/controller/pcie-mt7621.c
index 01ead2f92e87..9dfa5075b980 100644
--- a/drivers/pci/controller/pcie-mt7621.c
+++ b/drivers/pci/controller/pcie-mt7621.c
@@ -480,8 +480,8 @@ static int mt7621_pcie_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	pcie->dev = dev;
diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c
index fe288fd770c4..47500ed59608 100644
--- a/drivers/pci/controller/pcie-rcar-host.c
+++ b/drivers/pci/controller/pcie-rcar-host.c
@@ -952,8 +952,8 @@ static int rcar_pcie_probe(struct platform_device *pdev)
 	int err;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*host));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	host = pci_host_bridge_priv(bridge);
 	pcie = &host->pcie;
diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
index ee1822ca01db..225a5200f7a6 100644
--- a/drivers/pci/controller/pcie-rockchip-host.c
+++ b/drivers/pci/controller/pcie-rockchip-host.c
@@ -934,8 +934,8 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rockchip));
-	if (!bridge)
-		return -ENOMEM;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	rockchip = pci_host_bridge_priv(bridge);
 
diff --git a/drivers/pci/controller/pcie-xilinx-cpm.c b/drivers/pci/controller/pcie-xilinx-cpm.c
index d38f27e20761..1c14c5328ae0 100644
--- a/drivers/pci/controller/pcie-xilinx-cpm.c
+++ b/drivers/pci/controller/pcie-xilinx-cpm.c
@@ -574,8 +574,8 @@ static int xilinx_cpm_pcie_probe(struct platform_device *pdev)
 	int err;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*port));
-	if (!bridge)
-		return -ENODEV;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	port = pci_host_bridge_priv(bridge);
 
diff --git a/drivers/pci/controller/pcie-xilinx-dma-pl.c b/drivers/pci/controller/pcie-xilinx-dma-pl.c
index b037c8f315e4..0e68026671b8 100644
--- a/drivers/pci/controller/pcie-xilinx-dma-pl.c
+++ b/drivers/pci/controller/pcie-xilinx-dma-pl.c
@@ -771,8 +771,8 @@ static int xilinx_pl_dma_pcie_probe(struct platform_device *pdev)
 	int err;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*port));
-	if (!bridge)
-		return -ENODEV;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	port = pci_host_bridge_priv(bridge);
 
diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
index 05b8c205493c..a23f5e677c17 100644
--- a/drivers/pci/controller/pcie-xilinx-nwl.c
+++ b/drivers/pci/controller/pcie-xilinx-nwl.c
@@ -834,8 +834,8 @@ static int nwl_pcie_probe(struct platform_device *pdev)
 	int err;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENODEV;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	platform_set_drvdata(pdev, pcie);
diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 937ea6ae1ac4..7631af1ef6af 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -574,8 +574,8 @@ static int xilinx_pcie_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
-	if (!bridge)
-		return -ENODEV;
+	if (IS_ERR_OR_NULL(bridge))
+		return PTR_ERR(bridge);
 
 	pcie = pci_host_bridge_priv(bridge);
 	mutex_init(&pcie->map_lock);
diff --git a/drivers/pci/controller/plda/pcie-plda-host.c b/drivers/pci/controller/plda/pcie-plda-host.c
index 8e2db2e5b64b..28d638067adc 100644
--- a/drivers/pci/controller/plda/pcie-plda-host.c
+++ b/drivers/pci/controller/plda/pcie-plda-host.c
@@ -598,8 +598,8 @@ int plda_pcie_host_init(struct plda_pcie_rp *port, struct pci_ops *ops,
 				     "failed to map config memory\n");
 
 	bridge = devm_pci_alloc_host_bridge(dev, 0);
-	if (!bridge)
-		return dev_err_probe(dev, -ENOMEM,
+	if (IS_ERR_OR_NULL(bridge))
+		return dev_err_probe(dev, PTR_ERR(bridge),
 				     "failed to alloc bridge\n");
 
 	if (port->host_ops && port->host_ops->host_init) {
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index f41128f91ca7..e627f36b7683 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -686,18 +686,18 @@ struct pci_host_bridge *devm_pci_alloc_host_bridge(struct device *dev,
 
 	bridge = pci_alloc_host_bridge(priv);
 	if (!bridge)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	bridge->dev.parent = dev;
 
 	ret = devm_add_action_or_reset(dev, devm_pci_alloc_host_bridge_release,
 				       bridge);
 	if (ret)
-		return NULL;
+		return ERR_PTR(ret);
 
 	ret = devm_of_pci_bridge_init(dev, bridge);
 	if (ret)
-		return NULL;
+		return ERR_PTR(ret);
 
 	return bridge;
 }
@@ -3198,7 +3198,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 
 	bridge = pci_alloc_host_bridge(0);
 	if (!bridge)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	bridge->dev.parent = parent;
 
-- 
2.50.1


_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH RFC] PCI: Convert devm_pci_alloc_host_bridge() users to error-pointer returns
  2025-09-21 16:14 [PATCH RFC] PCI: Convert devm_pci_alloc_host_bridge() users to error-pointer returns Alok Tiwari
@ 2025-09-21 17:19 ` Marc Zyngier
  2025-09-22 10:55 ` AngeloGioacchino Del Regno
  1 sibling, 0 replies; 3+ messages in thread
From: Marc Zyngier @ 2025-09-21 17:19 UTC (permalink / raw)
  To: Alok Tiwari
  Cc: thomas.petazzoni, pali, lpieralisi, kwilczynski, mani, robh,
	bhelgaas, joyce.ooi, alyssa, jim2101024, florian.fainelli,
	bcm-kernel-feedback-list, rjui, sbranden, ryder.lee, jianjun.wang,
	sergio.paracuellos, matthias.bgg, angelogioacchino.delregno,
	marek.vasut+renesas, yoshihiro.shimoda.uh, geert+renesas,
	magnus.damm, shawn.lin, heiko, michal.simek, bharat.kumar.gogada,
	will, kys, haiyangz, wei.liu, decui, linus.walleij,
	thierry.reding, jonathanh, rric, nirmal.patel, toan,
	jonathan.derrick, linux-pci, linux-arm-kernel, linux-kernel,
	linux-rpi-kernel, linux-mediatek, linux-renesas-soc,
	linux-rockchip, linux-hyperv, linux-tegra

On Sun, 21 Sep 2025 17:14:07 +0100,
Alok Tiwari <alok.a.tiwari@oracle.com> wrote:
> 
> devm_pci_alloc_host_bridge() and pci_alloc_host_bridge() previously
> returned NULL on failure, forcing callers to special-case NULL handling
> and often hardcode -ENOMEM as the error.
> 
> This series updates devm_pci_alloc_host_bridge() to consistently return
> error pointers (ERR_PTR) with the actual error code, instead of NULL.
> All callers across PCI host controller drivers are updated to use
> IS_ERR_OR_NULL()/PTR_ERR() instead of NULL checks and hardcoded -ENOMEM.
> 
> Benefits:
>   - Standardizes error handling with Linux kernel ERR_PTR()/PTR_ERR()
>     conventions.
>   - Ensures that the actual error code from lower-level helpers is
>     propagated back to the caller.
>   - Removes ambiguity between NULL and error pointer returns.
>
> Touched drivers include:
>  cadence (J721E, cadence-plat)
>  dwc (designware, qcom)
>  mobiveil (layerscape-gen4, mobiveil-plat)
>  aardvark, ftpci100, ixp4xx, loongson, mvebu, rcar, tegra, v3-semi,
>  versatile, xgene, altera, brcmstb, iproc, mediatek, mt7621, xilinx,
>  plda, and others
> 
> This patch updates error handling across these host controller drivers
>  so that callers consistently receive ERR_PTR() instead of NULL.

Not quite.

> diff --git a/arch/mips/pci/pci-xtalk-bridge.c b/arch/mips/pci/pci-xtalk-bridge.c
> index e00c38620d14..c2c8ed8ecac1 100644
> --- a/arch/mips/pci/pci-xtalk-bridge.c
> +++ b/arch/mips/pci/pci-xtalk-bridge.c
> @@ -636,8 +636,8 @@ static int bridge_probe(struct platform_device *pdev)
>  	pci_set_flags(PCI_PROBE_ONLY);
>  
>  	host = devm_pci_alloc_host_bridge(dev, sizeof(*bc));
> -	if (!host) {
> -		err = -ENOMEM;
> +	if (IS_ERR_OR_NULL(host)) {
> +		err = PTR_ERR(host);

Under which circumstances can NULL still be returned? Because applying
PTR_ERR() to a NULL pointer looks like a pretty bad idea.

>  		goto err_remove_domain;
>  	}
>  

[...]

> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index f41128f91ca7..e627f36b7683 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -686,18 +686,18 @@ struct pci_host_bridge *devm_pci_alloc_host_bridge(struct device *dev,
>  
>  	bridge = pci_alloc_host_bridge(priv);
>  	if (!bridge)
> -		return NULL;
> +		return ERR_PTR(-ENOMEM);
>  
>  	bridge->dev.parent = dev;
>  
>  	ret = devm_add_action_or_reset(dev, devm_pci_alloc_host_bridge_release,
>  				       bridge);
>  	if (ret)
> -		return NULL;
> +		return ERR_PTR(ret);
>  
>  	ret = devm_of_pci_bridge_init(dev, bridge);
>  	if (ret)
> -		return NULL;
> +		return ERR_PTR(ret);
>  
>  	return bridge;
>  }
> @@ -3198,7 +3198,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
>  
>  	bridge = pci_alloc_host_bridge(0);
>  	if (!bridge)
> -		return NULL;
> +		return ERR_PTR(-ENOMEM);
>  
>  	bridge->dev.parent = parent;
>  

And what about the code that comes after that if we fail to register
the bus? The remaining "return NULL", which will then be interpreted
as 0 in any user of this function, leading to a worse situation than
what we have now.

Also, things like pci_scan_root_bus() have the following pattern:

	b = pci_create_root_bus(parent, bus, ops, sysdata, resources);
	if (!b)
		return NULL;

which will end with prejudice given what you have introduced.

If you are going to touch this sort of things, at least make it
consistent, analyse *all* code paths, and provide documentation.

	M.

-- 
Jazz isn't dead. It just smells funny.

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH RFC] PCI: Convert devm_pci_alloc_host_bridge() users to error-pointer returns
  2025-09-21 16:14 [PATCH RFC] PCI: Convert devm_pci_alloc_host_bridge() users to error-pointer returns Alok Tiwari
  2025-09-21 17:19 ` Marc Zyngier
@ 2025-09-22 10:55 ` AngeloGioacchino Del Regno
  1 sibling, 0 replies; 3+ messages in thread
From: AngeloGioacchino Del Regno @ 2025-09-22 10:55 UTC (permalink / raw)
  To: Alok Tiwari, thomas.petazzoni, pali, lpieralisi, kwilczynski,
	mani, robh, bhelgaas, joyce.ooi, alyssa, maz, jim2101024,
	florian.fainelli, bcm-kernel-feedback-list, rjui, sbranden,
	ryder.lee, jianjun.wang, sergio.paracuellos, matthias.bgg,
	marek.vasut+renesas, yoshihiro.shimoda.uh, geert+renesas,
	magnus.damm, shawn.lin, heiko, michal.simek, bharat.kumar.gogada,
	will, kys, haiyangz, wei.liu, decui, linus.walleij,
	thierry.reding, jonathanh, rric, nirmal.patel, toan,
	jonathan.derrick, linux-pci
  Cc: linux-arm-kernel, linux-kernel, linux-rpi-kernel, linux-mediatek,
	linux-renesas-soc, linux-rockchip, linux-hyperv, linux-tegra

Il 21/09/25 18:14, Alok Tiwari ha scritto:
> devm_pci_alloc_host_bridge() and pci_alloc_host_bridge() previously
> returned NULL on failure, forcing callers to special-case NULL handling
> and often hardcode -ENOMEM as the error.
> 
> This series updates devm_pci_alloc_host_bridge() to consistently return
> error pointers (ERR_PTR) with the actual error code, instead of NULL.
> All callers across PCI host controller drivers are updated to use
> IS_ERR_OR_NULL()/PTR_ERR() instead of NULL checks and hardcoded -ENOMEM.
> 
> Benefits:
>    - Standardizes error handling with Linux kernel ERR_PTR()/PTR_ERR()
>      conventions.
>    - Ensures that the actual error code from lower-level helpers is
>      propagated back to the caller.
>    - Removes ambiguity between NULL and error pointer returns.
> 
> Touched drivers include:
>   cadence (J721E, cadence-plat)
>   dwc (designware, qcom)
>   mobiveil (layerscape-gen4, mobiveil-plat)
>   aardvark, ftpci100, ixp4xx, loongson, mvebu, rcar, tegra, v3-semi,
>   versatile, xgene, altera, brcmstb, iproc, mediatek, mt7621, xilinx,
>   plda, and others
> 
> This patch updates error handling across these host controller drivers
>   so that callers consistently receive ERR_PTR() instead of NULL.
> 

I think that's a nice improvement - propagating the right error code looks good.

The only thing is - you have to make sure that it never returns NULL, so that
in the controller drivers you always check for `if (IS_ERR(x))` - otherwise with
the current IS_ERR_OR_NULL(x) most of the error paths are wrong.

Cheers,
Angelo

> Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
> ---
>   arch/mips/pci/pci-xtalk-bridge.c                       | 4 ++--
>   drivers/pci/controller/cadence/pci-j721e.c             | 4 ++--
>   drivers/pci/controller/cadence/pcie-cadence-plat.c     | 4 ++--
>   drivers/pci/controller/dwc/pcie-designware-host.c      | 4 ++--
>   drivers/pci/controller/dwc/pcie-qcom.c                 | 4 ++--
>   drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c | 4 ++--
>   drivers/pci/controller/mobiveil/pcie-mobiveil-plat.c   | 4 ++--
>   drivers/pci/controller/pci-aardvark.c                  | 4 ++--
>   drivers/pci/controller/pci-ftpci100.c                  | 4 ++--
>   drivers/pci/controller/pci-host-common.c               | 4 ++--
>   drivers/pci/controller/pci-hyperv.c                    | 4 ++--
>   drivers/pci/controller/pci-ixp4xx.c                    | 4 ++--
>   drivers/pci/controller/pci-loongson.c                  | 4 ++--
>   drivers/pci/controller/pci-mvebu.c                     | 4 ++--
>   drivers/pci/controller/pci-rcar-gen2.c                 | 4 ++--
>   drivers/pci/controller/pci-tegra.c                     | 4 ++--
>   drivers/pci/controller/pci-v3-semi.c                   | 4 ++--
>   drivers/pci/controller/pci-versatile.c                 | 4 ++--
>   drivers/pci/controller/pci-xgene.c                     | 4 ++--
>   drivers/pci/controller/pcie-altera.c                   | 4 ++--
>   drivers/pci/controller/pcie-brcmstb.c                  | 4 ++--
>   drivers/pci/controller/pcie-iproc-bcma.c               | 4 ++--
>   drivers/pci/controller/pcie-iproc-platform.c           | 4 ++--
>   drivers/pci/controller/pcie-mediatek-gen3.c            | 4 ++--
>   drivers/pci/controller/pcie-mediatek.c                 | 4 ++--
>   drivers/pci/controller/pcie-mt7621.c                   | 4 ++--
>   drivers/pci/controller/pcie-rcar-host.c                | 4 ++--
>   drivers/pci/controller/pcie-rockchip-host.c            | 4 ++--
>   drivers/pci/controller/pcie-xilinx-cpm.c               | 4 ++--
>   drivers/pci/controller/pcie-xilinx-dma-pl.c            | 4 ++--
>   drivers/pci/controller/pcie-xilinx-nwl.c               | 4 ++--
>   drivers/pci/controller/pcie-xilinx.c                   | 4 ++--
>   drivers/pci/controller/plda/pcie-plda-host.c           | 4 ++--
>   drivers/pci/probe.c                                    | 8 ++++----
>   34 files changed, 70 insertions(+), 70 deletions(-)
> 

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-09-22 10:55 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2025-09-21 16:14 [PATCH RFC] PCI: Convert devm_pci_alloc_host_bridge() users to error-pointer returns Alok Tiwari
2025-09-21 17:19 ` Marc Zyngier
2025-09-22 10:55 ` AngeloGioacchino Del Regno

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