mount-util: shorten the loop a bit (#7545)

The loop preparation and part of the loop contents are actually the
same, let's merge this.

Also, it's so much fun tweaking around in the name_to_handle_at() code,
let's do more of it with this patch!

(This also adds two NULL assignments, that aren't strictly necessary.
However, I figured its safer to place them in there, just in case the
for() condition is changed later. After all the freeing of the handle
and the invalidation of the cleanup-controller pointer to it are
otherwise really far away from each other...)

1 files changed, 8 insertions, 13 deletions

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index 7f8b53f2b5..f8d615dd89 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -55,7 +55,7 @@ int name_to_handle_at_loop(
                 int *ret_mnt_id,
                 int flags) {
 
-        _cleanup_free_ struct file_handle *h;
+        _cleanup_free_ struct file_handle *h = NULL;
         size_t n = ORIGINAL_MAX_HANDLE_SZ;
 
         /* We need to invoke name_to_handle_at() in a loop, given that it might return EOVERFLOW when the specified
@@ -65,15 +65,15 @@ int name_to_handle_at_loop(
          * This improves on raw name_to_handle_at() also in one other regard: ret_handle and ret_mnt_id can be passed
          * as NULL if there's no interest in either. */
 
-        h = malloc0(offsetof(struct file_handle, f_handle) + n);
-        if (!h)
-                return -ENOMEM;
-
-        h->handle_bytes = n;
-
         for (;;) {
                 int mnt_id = -1;
 
+                h = malloc0(offsetof(struct file_handle, f_handle) + n);
+                if (!h)
+                        return -ENOMEM;
+
+                h->handle_bytes = n;
+
                 if (name_to_handle_at(fd, path, h, &mnt_id, flags) >= 0) {
 
                         if (ret_handle) {
@@ -110,12 +110,7 @@ int name_to_handle_at_loop(
                 if (offsetof(struct file_handle, f_handle) + n < n) /* check for addition overflow */
                         return -EOVERFLOW;
 
-                free(h);
-                h = malloc0(offsetof(struct file_handle, f_handle) + n);
-                if (!h)
-                        return -ENOMEM;
-
-                h->handle_bytes = n;
+                h = mfree(h);
         }
 }