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From:   Zhenzhong Duan <zhenzhong.duan@gmail.com>
To:     linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Cc:     bhelgaas@google.com, hch@infradead.org,
        Zhenzhong Duan <zhenzhong.duan@gmail.com>
Subject: [PATCH v2] PCI: check also dynamic IDs for duplicate in new_id_store()
Date:   Mon, 26 Oct 2020 11:57:10 +0800
Message-Id: <20201026035710.593-1-zhenzhong.duan@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When a device ID data is writen to /sys/bus/pci/drivers/.../new_id,
only static ID table is checked for duplicate and multiple dynamic ID
entries of same kind are allowed to exist in a dynamic linked list.

Fix it by calling pci_match_device() which checks both dynamic and static
IDs.

After fix, it shows below result which is expected.

echo "1af4:1000" > /sys/bus/pci/drivers/vfio-pci/new_id
echo "1af4:1000" > /sys/bus/pci/drivers/vfio-pci/new_id
-bash: echo: write error: File exists

Drop the static specifier and add a prototype to avoid build error.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com>
---
v2: revert the export of pci_match_device() per Christoph
    combind PATCH1 and PATCH2 into one.

 drivers/pci/pci-driver.c | 4 ++--
 include/linux/pci.h      | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 8b587fc..cdc7d13 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -125,7 +125,7 @@ static ssize_t new_id_store(struct device_driver *driver, const char *buf,
 		pdev->subsystem_device = subdevice;
 		pdev->class = class;
 
-		if (pci_match_id(pdrv->id_table, pdev))
+		if (pci_match_device(pdrv, pdev))
 			retval = -EEXIST;
 
 		kfree(pdev);
@@ -250,7 +250,7 @@ const struct pci_device_id *pci_match_id(const struct pci_device_id *ids,
  * system is in its list of supported devices.  Returns the matching
  * pci_device_id structure or %NULL if there is no match.
  */
-static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
+const struct pci_device_id *pci_match_device(struct pci_driver *drv,
 						    struct pci_dev *dev)
 {
 	struct pci_dynid *dynid;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 22207a7..ec57312 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1409,6 +1409,8 @@ int pci_add_dynid(struct pci_driver *drv,
 		  unsigned long driver_data);
 const struct pci_device_id *pci_match_id(const struct pci_device_id *ids,
 					 struct pci_dev *dev);
+const struct pci_device_id *pci_match_device(struct pci_driver *drv,
+					     struct pci_dev *dev);
 int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 		    int pass);
 
-- 
1.8.3.1