[PATCH v2 2/2] lib/test_kho: use kho_preserve_vmalloc instead of storing addresses in fdt

[Mike Rapoport]

From: "Mike Rapoport (Microsoft)" <r...@kernel.org>

KHO test stores physical addresses of the preserved folios directly in
fdt.
Use kho_preserve_vmalloc() instead of it and kho_restore_vmalloc() to
retrieve the addresses after kexec.

This makes the test more scalable from one side and adds tests coverage
for kho_preserve_vmalloc() from the other.

Signed-off-by: Mike Rapoport (Microsoft) <r...@kernel.org>
---
 lib/test_kho.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/lib/test_kho.c b/lib/test_kho.c
index c2eb899c3b45..10045f5979a0 100644
--- a/lib/test_kho.c
+++ b/lib/test_kho.c
@@ -32,6 +32,7 @@ module_param(max_mem, long, 0644);
 struct kho_test_state {
        unsigned int nr_folios;
        struct folio **folios;
+       phys_addr_t *folios_info;
        struct folio *fdt;
        __wsum csum;
 };
@@ -68,13 +69,17 @@ static struct notifier_block kho_test_nb = {
 static int kho_test_save_data(struct kho_test_state *state, void *fdt)
 {
        phys_addr_t *folios_info __free(kvfree) = NULL;
+       phys_addr_t folios_info_phys;
        int err = 0;
 
-       folios_info = kvmalloc_array(state->nr_folios, sizeof(*folios_info),
-                                    GFP_KERNEL);
+       folios_info = vmalloc_array(state->nr_folios, sizeof(*folios_info));
        if (!folios_info)
                return -ENOMEM;
 
+       err = kho_preserve_vmalloc(folios_info, &folios_info_phys);
+       if (err)
+               return err;
+
        for (int i = 0; i < state->nr_folios; i++) {
                struct folio *folio = state->folios[i];
                unsigned int order = folio_order(folio);
@@ -89,11 +94,14 @@ static int kho_test_save_data(struct kho_test_state *state, 
void *fdt)
        err |= fdt_begin_node(fdt, "data");
        err |= fdt_property(fdt, "nr_folios", &state->nr_folios,
                            sizeof(state->nr_folios));
-       err |= fdt_property(fdt, "folios_info", folios_info,
-                           state->nr_folios * sizeof(*folios_info));
+       err |= fdt_property(fdt, "folios_info", &folios_info_phys,
+                           sizeof(folios_info_phys));
        err |= fdt_property(fdt, "csum", &state->csum, sizeof(state->csum));
        err |= fdt_end_node(fdt);
 
+       if (!err)
+               state->folios_info = no_free_ptr(folios_info);
+
        return err;
 }
 
@@ -197,7 +205,8 @@ static int kho_test_save(void)
 static int kho_test_restore_data(const void *fdt, int node)
 {
        const unsigned int *nr_folios;
-       const phys_addr_t *folios_info;
+       const phys_addr_t *folios_info_phys;
+       phys_addr_t *folios_info;
        const __wsum *old_csum;
        __wsum csum = 0;
        int len;
@@ -212,8 +221,12 @@ static int kho_test_restore_data(const void *fdt, int node)
        if (!old_csum || len != sizeof(*old_csum))
                return -EINVAL;
 
-       folios_info = fdt_getprop(fdt, node, "folios_info", &len);
-       if (!folios_info || len != sizeof(*folios_info) * *nr_folios)
+       folios_info_phys = fdt_getprop(fdt, node, "folios_info", &len);
+       if (!folios_info_phys || len != sizeof(*folios_info_phys))
+               return -EINVAL;
+
+       folios_info = kho_restore_vmalloc(*folios_info_phys);
+       if (!folios_info)
                return -EINVAL;
 
        for (int i = 0; i < *nr_folios; i++) {
@@ -233,6 +246,8 @@ static int kho_test_restore_data(const void *fdt, int node)
                folio_put(folio);
        }
 
+       vfree(folios_info);
+
        if (csum != *old_csum)
                return -EINVAL;
 
@@ -291,6 +306,7 @@ static void kho_test_cleanup(void)
                folio_put(kho_test_state.folios[i]);
 
        kvfree(kho_test_state.folios);
+       vfree(kho_test_state.folios_info);
 }
 
 static void __exit kho_test_exit(void)
-- 
2.50.1