[PATCH v2] target/s390x/arch_dump: Simplify memory allocation in s390x_write_elf64_notes()

[Thomas Huth]

We are not on a hot path here, so there is no real need for the logic
here with the split heap and stack space allocation. Simplify it by
always allocating memory from the heap.

Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 v2:
 - Added the missing "prev_size = note_size" (thanks, Janosch!)
 - Use g_free+g_malloc instead of g_realloc to avoid copying old contents

 target/s390x/arch_dump.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/target/s390x/arch_dump.c b/target/s390x/arch_dump.c
index a7c44ba49d..cb98f4894d 100644
--- a/target/s390x/arch_dump.c
+++ b/target/s390x/arch_dump.c
@@ -227,25 +227,25 @@ static int s390x_write_elf64_notes(const char *note_name,
                                        DumpState *s,
                                        const NoteFuncDesc *funcs)
 {
-    Note note, *notep;
+    g_autofree Note *notep = NULL;
     const NoteFuncDesc *nf;
-    int note_size, content_size;
+    int note_size, prev_size = 0, content_size;
     int ret = -1;
 
-    assert(strlen(note_name) < sizeof(note.name));
+    assert(strlen(note_name) < sizeof(notep->name));
 
     for (nf = funcs; nf->note_contents_func; nf++) {
-        notep = &note;
         if (nf->pvonly && !s390_is_pv()) {
             continue;
         }
 
         content_size = nf->note_size_func ? nf->note_size_func() : 
nf->contents_size;
-        note_size = sizeof(note) - sizeof(notep->contents) + content_size;
+        note_size = sizeof(Note) - sizeof(notep->contents) + content_size;
 
-        /* Notes with dynamic sizes need to allocate a note */
-        if (nf->note_size_func) {
+        if (prev_size < note_size) {
+            g_free(notep);
             notep = g_malloc(note_size);
+            prev_size = note_size;
         }
 
         memset(notep, 0, note_size);
@@ -258,15 +258,9 @@ static int s390x_write_elf64_notes(const char *note_name,
         /* Get contents and write them out */
         (*nf->note_contents_func)(notep, cpu, id);
         ret = f(notep, note_size, s);
-
-        if (nf->note_size_func) {
-            g_free(notep);
-        }
-
         if (ret < 0) {
             return -1;
         }
-
     }
 
     return 0;
-- 
2.31.1