scm: fix scm_fp_list->list initialization made in wrong place

This is the next page of the scm recursion story (the commit f8d570a4 net: Fix recursive descent in __scm_destroy()).

In function scm_fp_dup(), the INIT_LIST_HEAD(&fpl->list) of newly created fpl is done *before* the subsequent memcpy from the old structure and thus the freshly initialized list is overwritten.

But that's OK, since this initialization is not required at all, since the fpl->list is list_add-ed at the destruction time in any case (and is unused in other code), so I propose to drop both initializations, rather than moving it after the memcpy.

Please, correct me if I miss something significant.

---

index ab242cc..b12303d 100644
@@ -75,7 +75,6 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
 		if (!fpl)
 			return -ENOMEM;
 		*fplp = fpl;
-		INIT_LIST_HEAD(&fpl->list);
 		fpl->count = 0;
 	}
 	fpp = &fpl->fp[fpl->count];

@@ -301,7 +300,6 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
 
 	new_fpl = kmalloc(sizeof(*fpl), GFP_KERNEL);
 	if (new_fpl) {
-		INIT_LIST_HEAD(&new_fpl->list);
 		for (i=fpl->count-1; i>=0; i--)
 			get_file(fpl->fp[i]);
 		memcpy(new_fpl, fpl, sizeof(*fpl));

From: Pavel Emelyanov <[email protected]>
Date: Fri, 14 Nov 2008 17:32:58 +0300

Yep, this is totally correct.

Linus even noticed this in my original patch but kept them there because they seemed harmless to him.

Patch applied to net-2.6, thanks!