[PATCH v6] x86/amd_node: Continue initialization even if SMN reservation fails

[Ilan Bonneau-Zamon <yolezz.secret@gmail.com>]

Currently, if reserving PCI config regions fails for a node, amd_smn_init()
exits early. However, keeping successfully reserved regions active helps
prevent userspace from accessing those registers even if one node fails.

Change amd_smn_init() to attempt reserving regions for all nodes
unconditionally, logging a warning on failure instead of exiting.

Suggested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Ilan Bonneau-Zamon <ilan.bonneauzamon@gmail.com>
---
Changes in v6:
- Attempt to reserve PCI config regions for all nodes unconditionally,
  logging a warning on failure instead of aborting initialization.
- Remove obsolete error cleanup labels and release helper function.

Changes in v5:
- Drop __free() cleanup helpers and custom release logic, switching to
  traditional goto cleanup pattern (as suggested by Borislav Petkov).
- Fix changelog attribution regarding brace removal (noted by Mario Limonciello).
- Update author sign-off to use legal name.

Changes in v4:
- Remove unnecessary braces around the kzalloc_objs() error check.
---
 arch/x86/kernel/amd_node.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/amd_node.c b/arch/x86/kernel/amd_node.c
index b7926ba3610a..c0391b081c0f 100644
--- a/arch/x86/kernel/amd_node.c
+++ b/arch/x86/kernel/amd_node.c
@@ -250,8 +250,8 @@ __setup("amd_smn_debugfs_enable", amd_smn_enable_dfs);
 
 static int __init amd_smn_init(void)
 {
-	u16 count, num_roots, roots_per_node, node, num_nodes;
-	struct pci_dev *root __free(pci_dev_put) = NULL;
+	u16 count, num_roots = 0, roots_per_node, node, num_nodes;
+	struct pci_dev *root = NULL;
 
 	if (!cpu_feature_enabled(X86_FEATURE_ZEN))
 		return 0;
@@ -261,19 +261,20 @@ static int __init amd_smn_init(void)
 	if (amd_roots)
 		return 0;
 
-	num_roots = 0;
 	while ((root = get_next_root(root))) {
 		pci_dbg(root, "Reserving PCI config space\n");
 
 		/*
-		 * There are a few SMN index/data pairs and other registers
-		 * that shouldn't be accessed by user space. So reserve the
-		 * entire PCI config space for simplicity rather than covering
-		 * specific registers piecemeal.
-		 */
+		* There are a few SMN index/data pairs and other registers
+		* that shouldn't be accessed by user space. So reserve the
+		* entire PCI config space simplicity rather than covering
+		* specific registers piecemeal.
+		*
+		* Continue attempt to reserve regions for all roots, and log
+		* a warning if reservation fails on a particular device.
+		*/
 		if (!pci_request_config_region_exclusive(root, 0, PCI_CFG_SPACE_SIZE, NULL)) {
-			pci_err(root, "Failed to reserve config space\n");
-			return -EEXIST;
+			pci_warn(root, "Failed to reserve config space\n");
 		}
 
 		num_roots++;
@@ -298,6 +299,7 @@ static int __init amd_smn_init(void)
 
 	count = 0;
 	node = 0;
+	root = NULL;
 	while (node < num_nodes && (root = get_next_root(root))) {
 		/* Use one root for each node and skip the rest. */
 		if (count++ % roots_per_node)
@@ -316,6 +318,7 @@ static int __init amd_smn_init(void)
 	}
 
 	return 0;
+
 }
 
 fs_initcall(amd_smn_init);
-- 
2.56.0