[PATCH v3 15/21] kho: initialize preserved memory map radix tree earlier

[Pratyush Yadav]

From: "Pratyush Yadav (Google)" <pratyush at kernel.org>

Currently the preserved memory radix tree is initialized from
kho_memory_init(), which happens relatively late in MM init. In a coming
patch, the tree will be used from kho_memory_init_early(). Move the tree
initialization there.

Simplify some of the code in kho_mem_retrieve() by getting rid of the
err variable and jumping to err directly.

Signed-off-by: Pratyush Yadav (Google) <pratyush at kernel.org>
---
 kernel/liveupdate/kexec_handover.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
index 2ddfc804cdf7..6e8682469bd7 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -1531,20 +1531,8 @@ static void __init kho_mem_retrieve(void)
 	const struct kho_radix_walk_cb cb = {
 		.leaf = kho_preserved_memory_reserve,
 	};
-	const void *fdt = kho_get_fdt();
-	int err;
 
-	/*
-	 * kho_get_mem_map() should always succeed. If it fails, kho_populate()
-	 * catches that and never sets kho_in.scratch_phys, which stops memory
-	 * retrieval.
-	 */
-	err = kho_radix_init_tree(&kho_in.radix_tree, kho_get_mem_map(fdt));
-	if (err)
-		goto err;
-
-	err = kho_radix_walk_tree(&kho_in.radix_tree, &cb, NULL);
-	if (err)
+	if (kho_radix_walk_tree(&kho_in.radix_tree, &cb, NULL))
 		goto err;
 
 	return;
@@ -1756,6 +1744,8 @@ fs_initcall(kho_init);
 
 void __init kho_memory_init_early(void)
 {
+	const void *fdt = kho_get_fdt();
+
 	if (!is_kho_boot())
 		return;
 
@@ -1765,6 +1755,20 @@ void __init kho_memory_init_early(void)
 	 * early.
 	 */
 	kho_scratch = phys_to_virt(kho_in.scratch_phys);
+
+	/*
+	 * kho_get_mem_map() should always succeed. If it fails, kho_populate()
+	 * catches that and never sets kho_in.fdt_phys.
+	 */
+	if (kho_radix_init_tree(&kho_in.radix_tree, kho_get_mem_map(fdt))) {
+		/*
+		 * Failed to initialize preserved memory radix tree. Clear FDT
+		 * and scratch so KHO users don't treat it as a KHO boot.
+		 */
+		kho_in.fdt_phys = 0;
+		kho_in.scratch_phys = 0;
+		return;
+	}
 }
 
 void __init kho_memory_init(void)
-- 
2.55.0.141.g00534a21ce-goog