Index: sbin/swapon/swapon.c
===================================================================
--- sbin/swapon/swapon.c	(revision 279210)
+++ sbin/swapon/swapon.c	(working copy)
@@ -313,7 +313,7 @@
 swap_on_geli_args(const char *mntops)
 {
 	const char *aalgo, *ealgo, *keylen_str, *sectorsize_str;
-	const char *aflag, *eflag, *lflag, *sflag;
+	const char *aflag, *eflag, *lflag, *tflag, *sflag;
 	char *p, *args, *token, *string, *ops;
 	int argsize, pagesize;
 	size_t pagesize_len;
@@ -321,7 +321,7 @@
 
 	/* Use built-in defaults for geli(8). */
 	aalgo = ealgo = keylen_str = "";
-	aflag = eflag = lflag = "";
+	aflag = eflag = lflag = tflag = "";
 
 	/* We will always specify sectorsize. */
 	sflag = " -s ";
@@ -365,6 +365,8 @@
 					free(ops);
 					return (NULL);
 				}
+			} else if ((p = strstr(token, "trim")) == token) {
+				tflag = " -t ";
 			} else if (strcmp(token, "sw") != 0) {
 				warnx("Invalid option: %s", token);
 				free(ops);
@@ -387,8 +389,8 @@
 		sectorsize_str = p;
 	}
 
-	argsize = asprintf(&args, "%s%s%s%s%s%s%s%s -d",
-	    aflag, aalgo, eflag, ealgo, lflag, keylen_str,
+	argsize = asprintf(&args, "%s%s%s%s%s%s%s%s%s -d",
+	    aflag, aalgo, eflag, ealgo, lflag, keylen_str, tflag,
 	    sflag, sectorsize_str);
 
 	free(ops);
Index: share/man/man5/fstab.5
===================================================================
--- share/man/man5/fstab.5	(revision 279210)
+++ share/man/man5/fstab.5	(working copy)
@@ -242,6 +242,7 @@
 .Dq ealgo ,
 .Dq aalgo ,
 .Dq keylen ,
+.Dq trim ,
 and
 .Dq sectorsize
 options may be passed to control those