[RESEND PATCH] PCI: hotplug: check the return of hotplug bridge

[RESEND PATCH] PCI: hotplug: check the return of hotplug bridge

[Guilherme Giacomo Simoes]

In some pci drivers, when the pci bridge is added if the process return an error,
the drivers don't check this and continue your execute normally.
Then, this patch change this drivers for check return of pci_hp_add_bridge(), and
if has an error, then the drivers call goto lable , free your mutex and return the
error for your caller.

Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com>
---
 drivers/pci/hotplug/cpci_hotplug_pci.c | 7 +++++--
 drivers/pci/hotplug/cpqphp_pci.c       | 9 ++++++---
 drivers/pci/hotplug/ibmphp_core.c      | 8 ++++++--
 drivers/pci/hotplug/pciehp_pci.c       | 7 +++++--
 drivers/pci/hotplug/shpchp_pci.c       | 7 +++++--
 drivers/pci/probe.c                    | 9 ++++++---
 6 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/hotplug/cpci_hotplug_pci.c b/drivers/pci/hotplug/cpci_hotplug_pci.c
index 6c48066acb44..2d3256795eab 100644
--- a/drivers/pci/hotplug/cpci_hotplug_pci.c
+++ b/drivers/pci/hotplug/cpci_hotplug_pci.c
@@ -269,8 +269,11 @@ int cpci_configure_slot(struct slot *slot)
 	parent = slot->dev->bus;
 
 	for_each_pci_bridge(dev, parent) {
-		if (PCI_SLOT(dev->devfn) == PCI_SLOT(slot->devfn))
-			pci_hp_add_bridge(dev);
+		if (PCI_SLOT(dev->devfn) == PCI_SLOT(slot->devfn)) {
+			ret = pci_hp_add_bridge(dev);
+			if (ret)
+				goto out;
+		}
 	}
 
 	pci_assign_unassigned_bridge_resources(parent->self);
diff --git a/drivers/pci/hotplug/cpqphp_pci.c b/drivers/pci/hotplug/cpqphp_pci.c
index e9f1fb333a71..5f6ce2c6385a 100644
--- a/drivers/pci/hotplug/cpqphp_pci.c
+++ b/drivers/pci/hotplug/cpqphp_pci.c
@@ -70,7 +70,7 @@ static void __iomem *detect_HRT_floating_pointer(void __iomem *begin, void __iom
 int cpqhp_configure_device(struct controller *ctrl, struct pci_func *func)
 {
 	struct pci_bus *child;
-	int num;
+	int num, ret = 0;
 
 	pci_lock_rescan_remove();
 
@@ -97,7 +97,10 @@ int cpqhp_configure_device(struct controller *ctrl, struct pci_func *func)
 	}
 
 	if (func->pci_dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
-		pci_hp_add_bridge(func->pci_dev);
+		ret = pci_hp_add_bridge(func->pci_dev);
+		if (ret)
+			goto out;
+
 		child = func->pci_dev->subordinate;
 		if (child)
 			pci_bus_add_devices(child);
@@ -107,7 +110,7 @@ int cpqhp_configure_device(struct controller *ctrl, struct pci_func *func)
 
  out:
 	pci_unlock_rescan_remove();
-	return 0;
+	return ret;
 }
 
 
diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c
index 197997e264a2..73a593c2993b 100644
--- a/drivers/pci/hotplug/ibmphp_core.c
+++ b/drivers/pci/hotplug/ibmphp_core.c
@@ -663,6 +663,7 @@ static int ibm_configure_device(struct pci_func *func)
 	int num;
 	int flag = 0;	/* this is to make sure we don't double scan the bus,
 					for bridged devices primarily */
+	int ret = 0;
 
 	pci_lock_rescan_remove();
 
@@ -690,7 +691,10 @@ static int ibm_configure_device(struct pci_func *func)
 		}
 	}
 	if (!(flag) && (func->dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)) {
-		pci_hp_add_bridge(func->dev);
+		ret = pci_hp_add_bridge(func->dev);
+		if (ret)
+			goto out;
+
 		child = func->dev->subordinate;
 		if (child)
 			pci_bus_add_devices(child);
@@ -698,7 +702,7 @@ static int ibm_configure_device(struct pci_func *func)
 
  out:
 	pci_unlock_rescan_remove();
-	return 0;
+	return ret;
 }
 
 /*******************************************************
diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index 65e50bee1a8c..0c4873c2ef3c 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -58,8 +58,11 @@ int pciehp_configure_device(struct controller *ctrl)
 		goto out;
 	}
 
-	for_each_pci_bridge(dev, parent)
-		pci_hp_add_bridge(dev);
+	for_each_pci_bridge(dev, parent) {
+		ret = pci_hp_add_bridge(dev);
+		if (ret)
+			goto out;
+	}
 
 	pci_assign_unassigned_bridge_resources(bridge);
 	pcie_bus_configure_settings(parent);
diff --git a/drivers/pci/hotplug/shpchp_pci.c b/drivers/pci/hotplug/shpchp_pci.c
index 36db0c3c4ea6..7db0ce966f1d 100644
--- a/drivers/pci/hotplug/shpchp_pci.c
+++ b/drivers/pci/hotplug/shpchp_pci.c
@@ -48,8 +48,11 @@ int shpchp_configure_device(struct slot *p_slot)
 	}
 
 	for_each_pci_bridge(dev, parent) {
-		if (PCI_SLOT(dev->devfn) == p_slot->device)
-			pci_hp_add_bridge(dev);
+		if (PCI_SLOT(dev->devfn) == p_slot->device) {
+			ret = pci_hp_add_bridge(dev);
+			if (ret)
+				goto out;
+		}
 	}
 
 	pci_assign_unassigned_bridge_resources(bridge);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b14b9876c030..2418998820dc 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3363,9 +3363,10 @@ int pci_hp_add_bridge(struct pci_dev *dev)
 		if (!pci_find_bus(pci_domain_nr(parent), busnr))
 			break;
 	}
+
 	if (busnr-- > end) {
 		pci_err(dev, "No bus number available for hot-added bridge\n");
-		return -1;
+		return -ENODEV;
 	}
 
 	/* Scan bridges that are already configured */
@@ -3380,8 +3381,10 @@ int pci_hp_add_bridge(struct pci_dev *dev)
 	/* Scan bridges that need to be reconfigured */
 	pci_scan_bridge_extend(parent, dev, busnr, available_buses, 1);
 
-	if (!dev->subordinate)
-		return -1;
+	if (!dev->subordinate) {
+		pci_err(dev, "No dev subordinate\n");
+		return -ENODEV;
+	}
 
 	return 0;
 }
-- 
2.46.0

Re: [RESEND PATCH] PCI: hotplug: check the return of hotplug bridge

[Bjorn Helgaas]

On Sat, Aug 31, 2024 at 10:28:21AM -0300, Guilherme Giacomo Simoes wrote:
> In some pci drivers, when the pci bridge is added if the process return an error,
> the drivers don't check this and continue your execute normally.
> Then, this patch change this drivers for check return of pci_hp_add_bridge(), and
> if has an error, then the drivers call goto lable , free your mutex and return the
> error for your caller.
> 
> Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com>

Did you see Lukas' response at
https://lore.kernel.org/r/ZsAzM8K9PnN5jxR9@wunner.de ?

AFAICT the discussion he pointed to is very relevant and needs to be
considered before we apply a patch like this.

If you have addressed those comments, please describe how you
addressed them in the commit log, and include links to Nam Cao's work
and cc them as well.

Bjorn