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From: Will Deacon <will@kernel.org>
To: iommu@lists.linuxfoundation.org, linux-kernel@vger.kernel.org
Cc: "Isaac J. Manjarres" <isaacm@codeaurora.org>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Saravana Kannan <saravanak@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Will Deacon <will@kernel.org>
Subject: [PATCH v3 05/14] iommu/of: Take a ref to the IOMMU driver during ->of_xlate()
Date: Thu, 21 Nov 2019 11:49:09 +0000	[thread overview]
Message-ID: <20191121114918.2293-6-will@kernel.org> (raw)
In-Reply-To: <20191121114918.2293-1-will@kernel.org>

Ensure that we hold a reference to the IOMMU driver module while calling
the '->of_xlate()' callback during early device probing.

Signed-off-by: Will Deacon <will@kernel.org>
---
 drivers/iommu/of_iommu.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 78faa9f73a91..25491403a0bd 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -8,6 +8,7 @@
 #include <linux/export.h>
 #include <linux/iommu.h>
 #include <linux/limits.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_iommu.h>
 #include <linux/of_pci.h>
@@ -89,16 +90,16 @@ static int of_iommu_xlate(struct device *dev,
 {
 	const struct iommu_ops *ops;
 	struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
-	int err;
+	int ret;
 
 	ops = iommu_ops_from_fwnode(fwnode);
 	if ((ops && !ops->of_xlate) ||
 	    !of_device_is_available(iommu_spec->np))
 		return NO_IOMMU;
 
-	err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
-	if (err)
-		return err;
+	ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
+	if (ret)
+		return ret;
 	/*
 	 * The otherwise-empty fwspec handily serves to indicate the specific
 	 * IOMMU device we're waiting for, which will be useful if we ever get
@@ -107,7 +108,12 @@ static int of_iommu_xlate(struct device *dev,
 	if (!ops)
 		return driver_deferred_probe_check_state(dev);
 
-	return ops->of_xlate(dev, iommu_spec);
+	if (!try_module_get(ops->owner))
+		return -ENODEV;
+
+	ret = ops->of_xlate(dev, iommu_spec);
+	module_put(ops->owner);
+	return ret;
 }
 
 struct of_pci_iommu_alias_info {
-- 
2.24.0.432.g9d3f5f5b63-goog

_______________________________________________
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iommu@lists.linux-foundation.org
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WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: iommu@lists.linuxfoundation.org, linux-kernel@vger.kernel.org
Cc: Will Deacon <will@kernel.org>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Jordan Crouse <jcrouse@codeaurora.org>,
	John Garry <john.garry@huawei.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Saravana Kannan <saravanak@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Isaac J. Manjarres" <isaacm@codeaurora.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Joerg Roedel <joro@8bytes.org>
Subject: [PATCH v3 05/14] iommu/of: Take a ref to the IOMMU driver during ->of_xlate()
Date: Thu, 21 Nov 2019 11:49:09 +0000	[thread overview]
Message-ID: <20191121114918.2293-6-will@kernel.org> (raw)
In-Reply-To: <20191121114918.2293-1-will@kernel.org>

Ensure that we hold a reference to the IOMMU driver module while calling
the '->of_xlate()' callback during early device probing.

Signed-off-by: Will Deacon <will@kernel.org>
---
 drivers/iommu/of_iommu.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 78faa9f73a91..25491403a0bd 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -8,6 +8,7 @@
 #include <linux/export.h>
 #include <linux/iommu.h>
 #include <linux/limits.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_iommu.h>
 #include <linux/of_pci.h>
@@ -89,16 +90,16 @@ static int of_iommu_xlate(struct device *dev,
 {
 	const struct iommu_ops *ops;
 	struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
-	int err;
+	int ret;
 
 	ops = iommu_ops_from_fwnode(fwnode);
 	if ((ops && !ops->of_xlate) ||
 	    !of_device_is_available(iommu_spec->np))
 		return NO_IOMMU;
 
-	err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
-	if (err)
-		return err;
+	ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
+	if (ret)
+		return ret;
 	/*
 	 * The otherwise-empty fwspec handily serves to indicate the specific
 	 * IOMMU device we're waiting for, which will be useful if we ever get
@@ -107,7 +108,12 @@ static int of_iommu_xlate(struct device *dev,
 	if (!ops)
 		return driver_deferred_probe_check_state(dev);
 
-	return ops->of_xlate(dev, iommu_spec);
+	if (!try_module_get(ops->owner))
+		return -ENODEV;
+
+	ret = ops->of_xlate(dev, iommu_spec);
+	module_put(ops->owner);
+	return ret;
 }
 
 struct of_pci_iommu_alias_info {
-- 
2.24.0.432.g9d3f5f5b63-goog


  parent reply	other threads:[~2019-11-21 11:49 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-21 11:49 [PATCH v3 00/14] iommu: Permit modular builds of ARM SMMU[v3] drivers Will Deacon
2019-11-21 11:49 ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 01/14] drivers/iommu: Export core IOMMU API symbols to permit modular drivers Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 02/14] iommu/of: Request ACS from the PCI core when configuring IOMMU linkage Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 03/14] PCI: Export pci_ats_disabled() as a GPL symbol to modules Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 04/14] drivers/iommu: Take a ref to the IOMMU driver prior to ->add_device() Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` Will Deacon [this message]
2019-11-21 11:49   ` [PATCH v3 05/14] iommu/of: Take a ref to the IOMMU driver during ->of_xlate() Will Deacon
2019-11-21 11:49 ` [PATCH v3 06/14] drivers/iommu: Allow IOMMU bus ops to be unregistered Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 07/14] Revert "iommu/arm-smmu: Make arm-smmu-v3 explicitly non-modular" Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 08/14] Revert "iommu/arm-smmu: Make arm-smmu " Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 09/14] iommu/arm-smmu: Prevent forced unbinding of Arm SMMU drivers Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-26  9:13   ` John Garry
2019-11-26  9:13     ` John Garry
2019-11-26 20:27     ` Saravana Kannan via iommu
2019-11-26 20:27       ` Saravana Kannan
2019-11-27 11:04       ` John Garry
2019-11-27 11:04         ` John Garry
2019-11-27 11:41         ` John Garry
2019-11-27 11:41           ` John Garry
2019-11-21 11:49 ` [PATCH v3 10/14] iommu/arm-smmu-v3: Unregister IOMMU and bus ops on device removal Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 11/14] iommu/arm-smmu-v3: Allow building as a module Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 12/14] iommu/arm-smmu: Unregister IOMMU and bus ops on device removal Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 13/14] iommu/arm-smmu: Allow building as a module Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-21 11:49 ` [PATCH v3 14/14] iommu/arm-smmu: Update my email address in MODULE_AUTHOR() Will Deacon
2019-11-21 11:49   ` Will Deacon
2019-11-22 17:41 ` [PATCH] iommu/arm-smmu: support SMMU module probing from the IORT Ard Biesheuvel
2019-11-22 17:41   ` Ard Biesheuvel
2019-11-25 12:16   ` Robin Murphy
2019-11-25 12:16     ` Robin Murphy
2019-11-25 16:04   ` Lorenzo Pieralisi
2019-11-25 16:04     ` Lorenzo Pieralisi
2019-11-27 16:20     ` John Garry
2019-11-27 16:20       ` John Garry

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