From: Yuan Can <yuancan@huawei.com>
Date: Sat, 5 Nov 2022 09:43:09 +0000 (+0000)
Subject: NTB: amd: Fix error handling in amd_ntb_pci_driver_init()
X-Git-Tag: v6.6.7~2382^2~12
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=98af0a33c1101c29b3ce4f0cf4715fd927c717f9;p=platform%2Fkernel%2Flinux-starfive.git

NTB: amd: Fix error handling in amd_ntb_pci_driver_init()

A problem about ntb_hw_amd create debugfs failed is triggered with the
following log given:

 [  618.431232] AMD(R) PCI-E Non-Transparent Bridge Driver 1.0
 [  618.433284] debugfs: Directory 'ntb_hw_amd' with parent '/' already present!

The reason is that amd_ntb_pci_driver_init() returns pci_register_driver()
directly without checking its return value, if pci_register_driver()
failed, it returns without destroy the newly created debugfs, resulting
the debugfs of ntb_hw_amd can never be created later.

 amd_ntb_pci_driver_init()
   debugfs_create_dir() # create debugfs directory
   pci_register_driver()
     driver_register()
       bus_add_driver()
         priv = kzalloc(...) # OOM happened
   # return without destroy debugfs directory

Fix by removing debugfs when pci_register_driver() returns error.

Fixes: a1b3695820aa ("NTB: Add support for AMD PCI-Express Non-Transparent Bridge")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
---

diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.c b/drivers/ntb/hw/amd/ntb_hw_amd.c
index 04550b1..730f210 100644
--- a/drivers/ntb/hw/amd/ntb_hw_amd.c
+++ b/drivers/ntb/hw/amd/ntb_hw_amd.c
@@ -1338,12 +1338,17 @@ static struct pci_driver amd_ntb_pci_driver = {
 
 static int __init amd_ntb_pci_driver_init(void)
 {
+	int ret;
 	pr_info("%s %s\n", NTB_DESC, NTB_VER);
 
 	if (debugfs_initialized())
 		debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 
-	return pci_register_driver(&amd_ntb_pci_driver);
+	ret = pci_register_driver(&amd_ntb_pci_driver);
+	if (ret)
+		debugfs_remove_recursive(debugfs_dir);
+
+	return ret;
 }
 module_init(amd_ntb_pci_driver_init);